bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Properties of Thick-Film Front Silver Electrodes for Silicon Solar Cells
Authors: Fu Ming , Jin Gong Lei , Ding Xiao , Fan Lin , Chen Dong
Published: March 2013

The front electrode is usually made by the screen printing thick-film silver pastes and the high-temperature firing process in industrial production of silicon solar cells. This paper analyzed the ohmic contact mechanism of thick-film front silver electrodes and studied the microstructure of Ag-Si interface by SEM. The paste samples, used to form front silver electrodes of silicon solar cells, were prepared. Thick-film silver electrodes were printed on silicon wafers with different sheet resistances, and the relationships between the sheet resistances and the contact properties were investigated by changing the firing temperature. By adding right amount of phosphorus compounds to the silver paste, the effects of the donor-doping (N-doping) concentrations on the series resistance of cells were studied. The experimental results show that firing temperature is critical to the Ag-Si ohmic contact, particularly when the silver pastes are designed for the wafers with high sheet resistance and the right amount of N-doping addition in the paste may decrease the series resistances of solar cells.
Synthesis and Characterization of Graphene Sheets as an Anode Material for Lithium-Ion Batteries
Authors: Dong Lei , Ren Wei , Dong Lei , Li De Jun
Published: March 2013

The graphene sheets were obtained using rapid thermal expansion in nitrogen atmosphere from graphene oxide sheets prepared from graphite powder through improved Hummers’ method. The structure and morphology of the graphene sheets as anode materials with different dimensions were characterized through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM). The electrochemical performances were evaluated in coin-type cells versus metallic lithium. The results showed that graphene as the two dimensional nanomaterials possessed more advantages in microstructure and better Li-ions intercalation performances than the traditional materials.
Study on the Fabrication and Properties of Ni-P Composite Coating
Authors: An Zhao , Li Ming Ya , Ge Nian Hao , Li Xiao Ying , Li Qiu Fan , Chen Min
Published: March 2013

In this paper, the method of electroless deposition of nickel-phosphorous composite coating on the sample surface is employed. The effect of the complexing agent ratio on the surface morphology and phase composition of nickel-phosphorus coating when the main salt and reducing agent concentration unchanged has been studied. The influence of heat treatment on properties and microstructure of coatings are also investigated. Experimental results show that in the case of salt and reducing agent concentration unchanged, complexing agent concentration has strong effect on the morphology of the coatings and the crystal structure of the composite coating. During heat treatment, the morphology of the composite coating changed significantly, and the hardness was improved a certain degree for all the samples, which is related to the precipitation of Ni3P.
Effects of Nanoparticles on the Properties of Chrome-Free Dacromet Coatings
Authors: Tang Yi Ping , Wei Cheng Dong , Hou Guang Ya , Cao Hua Zhen , Zheng Guo Qu
Published: March 2013

Chrome-free Dacromet coating is a green anti-corrosion technology. This paper studied the effects of nanoparticles of TiO2 and SiO2 on the coatings. The results shown the addition of nano-TiO2 (T-coating )improved the physical properties and corrosion resistance. The addition of nano-SiO2 (S-coating )was week bonded with zinc and aluminium powders, resulting in the poor properties.
Effect of Yb2SiO5 Ceramic Layer Thickness on the Thermal Cycling Life of Yb2SiO5⁄LaMgAl11O19 Coating Deposited on C⁄SiC Composites
Authors: Wang Ying , Zou Bing Lin , Fan Xi Zhi , Cao Xue Qiang
Published: March 2013

C⁄SiC composites were plasma sprayed with Yb2SiO5⁄LaMgAl11O19 (LMA) coatings with varying Yb2SiO5 layer thickness. The effect of Yb2SiO5 layer thickness on the thermal cycling life of the Yb2SiO5LMA coatings was investigated. The results showed that the thermal cycling life is significantly dependent on the Yb2SiO5 layer thickness. It decreased from 130 cycles to 35 cycles as Yb2SiO5 layer thickness increased from 50 µm to 100 µm. Further increasing Yb2SiO5 layer thickness to 200 µm made it decrease to 2 cycles. The influencing mechanism of Yb2SiO5 layer thickness for the thermal cycling life was clarified based on the thermal expansion behavior, the chemical stability at high temperature and the microstructure analysis.
Tribological Performance of Ceramic Composite Coatings Obtained through Microarc Oxidation on Ly12 Aluminum Alloy
Authors: Li Shu Hua , Yin Yu Jun , Shen Da Wei , Zu Yuan Yuan , Qu Chang Zheng
Published: March 2013

A dense ceramic oxide coating approximately 30µm thick was prepared on a Ly12 Al alloy by microarc oxidation in an alkali-silicate electrolytic solution. The morphology and microstructure were analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD). Coating thickness and surface roughness (Ra) were measured after the coating had been synthesized. The tribological performance of the coatings was evaluated using a dry sand abrasion test and a solid particle erosion test. The results show that microarc oxidation coatings consist of the loose superficial layer and the inner dense layer. Both inner layer and out layer are composed of α-Al2O3 and γ-Al2O3, While the Al6Si2O3 phase is observed only in out loose layer. The average of the microhardness of the coating is 2096Hv.
Effects of Al2O3 on the Structure and Properties of Aluminoborosilicate Glasses
Authors: Zhang X.H. , Yue Y.L. , Wu H.T.
Published: March 2013

In alkaline earth aluminoborosilicate glasses CaO-B2O3-Al2O3-SiO2, the changes of structure and properties caused by variations in the ratio Al2O3/B2O3 were investigated. The structure was investigated by Fourier transform infrared spectroscopy. The dielectric constant and tangent loss were measured at 1 MHz. Chemical durability was evaluated by weight losses of glass samples after immersion in HCl and NaOH solutions. The results indicated that the fraction of four-coordinated boron atoms (N4), chemical durability and dielectric properties increased with increasing Al2O3/B2O3 replacements.
Novel Thermal-Electrical-Mechanical Model for Simulating Coupled Phenomena in High-Frequency Electronic Devices
Authors: Zhang Jing
Published: March 2013

We present a fully coupled thermal-electrical-mechanical finite element based model to study material degradation behaviors of high-frequency electronic devices. The mechanisms of degradation and ultimately failure in wide bandgap (WBG) devices are very complex. Under operating conditions, the devices are usually subject to high electric fields, high stress/strain fields, high current densities, high temperatures and high thermal gradients. Moreover, these phenomena are coupled together. The presented finite element model is capable of computing stress, temperature, and electric fields based on an innovative finite element approach for the solution of non-linear coupled thermal-electrical-mechanical problems. The model can be applied to wide bandgap electronic devices to address major issues of performance and lifetime.
Low-Temperature Synthesis of Nano-Crystalline Zn2SiO4 Powders by Aqueous Sol-Gel Process
Authors: Chen X.F. , Li J. , Feng T.T. , Jiang Y.S. , Zhang X.H. , Wu H.T. , Yue Y.L.
Published: March 2013

The willemite-type Zn2SiO4 was successfully synthesized by the aqueous sol-gel method using Si sols dioxide and zinc nitrate as starting materials instead of expensive organic solvent and metal alkoxides. The as-prepared nanopowders were characterized by X-ray diffraction (XRD), differential thermal analysis (DTA) and scanning electron microscope (SEM), respectively. The results showed that the calcination process of gel consisted of a series of oxidation and combustion reactions, accompanied by significantly exothermal effects. Highly reactive nanosized Zn2SiO4 powders were successfully obtained at 800 °C with particle size ~100 nm. By comparison, the aqueous sol-gel process was the most effective and least expensive technique used for the preparation of Zn2SiO4 nanopowders.
Microstructure and Photoluminescence Study of ZnO Films Prepared by Thermal Oxidation of Zn Metallic Films in Air
Authors: Shi Ming Ji , Zhang Dan , Chen Lan Li , Luo Peng Hui , Xiao Sa
Published: March 2013

In this thesis, Zn films were deposited on silicon substrates by high-speed galvanization, and then were treated in Muffle Resistance Furnace at 700°Cin an open-air environment. Polycrystalline ZnO films covered with ZnO nanorods were grown. Its morphologies were studied by SEM and its crystal structures were studied by XRD．Its photoluminescence spectrum was also measured．And possible mechanisms of the growth and the photoluminescence of ZnO nanorods were proposed to explain the experimental result．
Electrical Characteristics of Bismuth Titanate Ceramics and Glass-Ceramics, Containing SiO2 and Nd2O3 as Additives
Authors: Slavov Stanislav S. , Krapchanska Milena Z. , Kashchieva Elena P. , Parvanov Svetlin B. , Dimitriev Yanko B.
Published: March 2013

Bismuth-titanate ceramics containing SiO2and Nd2O3as additives are synthesized by melt quenching method in the system Bi2O3-TiO2-Nd2O3-SiO2at temperature 1450 oC. By X-ray diffraction analysis are determined the crystal phases participating in the materials: Bi4Ti3O12, Bi12TiO20and δ-Bi2O3. The addition of SiO2allows to control the glass formation ability of the supercooled melts. The addition of Nd2O3stimulates the thermal stability of the materials due to formation of solid solutions Bi4-xNdxTi3O12. Measurements of the electrical conductivity, capacitance and dielectric losses of selected samples are performed by DC resistible bridge and digital capacity meter (with frequency of 1 kHz) using two-terminal method and a suitable sample holder with graphite electrodes. It is established that for the investigated samples the activation energy of conductivity is in the range 1 – 1,3 eV, dielectric permittivity from 1000 to 3000 at (at 400 oC) and dielectric losses tgδ are between 0,0002 and 0,1.
Water Assisted Conversion of ZnO from Metallic Zinc Particles
Authors: Ma Qing Lan , Xiong Rui , Zhai Bao Gai , Huang Yuan Ming
Published: March 2013

Zinc oxide (ZnO) was synthesized by solid-liquid reaction of raw Zn particles in water. The synthesized ZnO were characterized with X-ray diffraction (XRD), scanning electronic microscopy (SEM) and photoluminescence (PL) spectrophotometer. The XRD pattern confirmed that the formation of ZnO with wurtzite structure and ZnOOH crystals. The SEM study clearly exhibited a honeycomb-shaped structure of the Zn/ZnO/ZnOOH composites. Room-temperature PL spectra have been observed a very weak UV emission at 376 nm and a very strong yellow-green emission at 538 nm. Furthermore, a possible mechanism of the water-assisted conversion of ZnO from metallic Zn particles was discussed.
Combustion Synthesis and Luminescent Properties of Eu3+ and Dy3+ Co-Doped Amorphous SrAl2O4
Authors: Zhai Bao Gai , Ma Qing Lan , Huang Yuan Ming
Published: March 2013

Trivalent Eu and Dy ions co-doped amorphous strontium aluminate oxide (SrAl2O4:Eu3+Dy3+) were synthesized through solution combustion route. The phase of the synthesized compound was examined with the X-ray diffractometry. The photoluminescence spectra of the amorphous SrAl2O4:Eu3+Dy3+ has shown that the sharp blue emission of Dy3+ at 483 nm, the sharp yellow emission of Dy3+ at 570 nm and the sharp red emission of Eu3+ at 615 nm can be integrated into the broad blue background emission of the amorphous host. The results indicate that the amorphous SrAl2O4 host can provide good environment to tune the emission color for the SrAl2O4:Eu3+Dy3+.
Thermally More Durable Electromechanical Films by POSS Nanomodification
Authors: Paajanen Mika , Karttunen Mikko , Kortet Satu , Härkki Outi , Orko Inka
Published: March 2013

The thermal stability of polypropylene (PP) based cellular electromechanical films was improved by compounding PP with thermally more durable cyclo olefin copolymer (COC) and polyhedral oligomeric silsesquioxane (POSS) nanochemical. The cast films were biaxially oriented in laboratory scale and then expanded by a gas diffusion expansion method, which increased the pore size inside the cellular film structure and the thickness of the film. The cellular films were then electrostatically charged by a contact charging method and metallized by gold sputtering. The samples were aged at 85°C showing that the d33 signal decreased from the original value, but remained at high level; more than 120 pC/N even after two weeks of ageing.
Quantitative Characterization of Hydration of Cement Pastes by Rietveld Phase Analysis and Thermoanalysis
Authors: Wei Yong Qi , Yao Wu
Published: March 2013

The quantitative characterization of hydration of cement pastes has always been one of focuses of researchers’ attention. Rietveld phase analysis (RPA), a combination of quantitative X-ray diffraction (QXRD) and the Rietveld method, supplies a tool of an enormous potential for that. Although a few of related researches were conducted by RPA, the reported attention was not paid to the neat cement paste with a low w/c ratio. Therefore, this work aimed at the quantitative study on hydration of such a cement paste chiefly by this method, meanwhile, cooperated with the hyphenated technique of thermogravimetry with differential scanning calorimetry (TG-DSC), as a spot check. Results indicated that RPA was a reliable method in quantitatively characterizing hydration of cement pastes, and gave a clear decription of evolution of all main crystal phases in cement pastes; and that the evolution of monosulphate(Afm_12) was also able to be tracked quantitatively. This will help to understand better the hydration mechanism of cement pastes, as well as to investigate quantitatively effects of mineral and chemical admixtures on hydration of composite cementitious systems.
Effect of Metakaolin on the Physical Properties and Setting Time of High Performance Concrete
Authors: Wang Bao Min , Ma Hai Nan , Li Ming , Han Yu
Published: March 2013

Abstract. Kaolin native to Jilin Province was calcined at the constant temperature of 750°C for 4 hours to obtain the high pozzolanic metakaolin(Al2Si2O7). The effects of metakaolin (MK) on the static flow expansion of cement paste and the workability and setting time of concrete were studied with the content of 0, 5%, 10% and 15% by weight of cementitious material. The test results show that: when the dosage of superplasticizer is 2% by weight of cementitious material, the setting time of concrete shortens obviously and the slump and expansion decrease with the raising of MK content. When 5% of cement is replaced by MK, the setting time of concrete shortens by 5%; the slump and the slump flow decrease by 5.5% and 4.4% respectively.
The Effect of Curing System on Mechanical Properties of Desulphurization Gypsum-Slag Composite Binder
Authors: Liu Xiao Qin , Wang Jun , Qin Hong Gen
Published: March 2013

Desulphurization gypsum-slag composite binder is a hydraulic composite binding material made by slag, desulphurization generated by coal-fired power plant flue gas desulphurization, activator and other materials. In order to study the effect of curing system on the composite binder, steam curing, autoclave curing, nature curing, standard curing and water curing were selected. The mechanical properties of desulphurization gypsum-slag composite binder were compared, and the best curing system for strength development was proposed.
Phosphate Bonding: A New Method for Using Large Volume of Fly Ash
Authors: Ding Zhu , Zhang Ming , Dong Bi Qin , Liu Wei , Lu Han
Published: March 2013

Magnesium phosphate cements (MPC) with larger volume of fly ash were studied in the present work. Dead burned magnesia, phosphates and fly ash were the components of MPC. The volume of fly ash in MPC was 70%, 75% and 80%, respectively. Three phosphates, monosodium phosphate (MSP), monopotassium phosphate (MPP) and monoammonium phosphate (MAP) were used. Compressive strength of the three MPC mortars with different fly ash content was determined. Results show that the compressive strength reduced with the proportion increase of fly ash, increased with the curing time. After cured 28 days in the lab air, the compressive strength of cement mortar can reach 14MPa, when the fly ash dosage was 80% by weight of cement. The reaction product is struvite of potassium (KMgPO4•6H2O) in potassium phosphate based MPC, and hydrated sodium phosphate (Na2HPO4•17H2O) in sodium phosphate based MPC. The results indicate that MPC has capacity to bond large volume of fly ash. A new way to utilize fly ash in a large scale can be realized by phosphate bonding.
Study on the Influence Factors of the Dispersion of Carbon Nanotubes in Aqueous Solution
Authors: Liu Xiao Yan , Xu Yue , Chen Lei , Wang Xin Rui , Zhou Mao Kun
Published: March 2013

In this paper, the optimal ratio of surfactant and carbon nanotubes (CNTs), the best ultrasonic time and the effects of three different surfactants were studied based on which the CNTs dispersion method was recommended. For each surfactant, optimal mix ratio of surfactant and CNTs could be found. The results of UV-Vis spectrophotometer test and centrifugation showed that the best CNTs dispersion could be obtained with OP, and the optimal mass ratio between OP and CNTs was about 0.7, and when the concentration of CNTs was 1g/L, the optimal ultrasonic time was about 1 hour. With the concentration of CNTs increased, the optimal ultrasonic time also increased.
Alkali Activity of Granite Aggregates and Control in the Concrete of the Three Gorges Project
Authors: Wang Zai Qin , Liu Chong Xi , Wen Zi Yun , Li Zhen , Xiao Liang
Published: March 2013

On the basis of the existing standardized test methods of concrete aggregates alkali activity, the alkali activity of the granite aggregates is studied by extending the observation time. The results showed that the alkali reaction expansion ratio of the fresh granite broke through the 0.1% criterion limit after a decade of time. The reactant microstructure characteristic is similar to the structure of the alkali-silica reaction, the thickness of reaction layer is about 2~4 µm. Controlling the total alkali content of the dam concrete and replacing cement by mixing a certain proportion of fly ash can effectively prevent the occurrence of the AAR in the Three Gorges Project.
The Length Optimization of Non-Stayed Cable Segment to Low-Pylon Cable-Stayed Bridge
Authors: Bi Hong Tao , Li Yan
Published: March 2013

An optimization model was proposed in order to investigate the effect of the non-stayed cable segment length on the performance of a low-pylon cable-stayed bridge. Based on the structural analysis of the cable-stayed bridges, the proposed model aims to adjust the structural internal force by changing the non-stayed cable segment length. The most reasonable length of non-stayed cable segment was obtained by the optimization analysis.
Time-Dependent Shear Capability Analysis and its Application of Reinforced Concrete Simply-Supported Beam Bridge
Authors: Lin Yang Zi , Tang Hai Hong , Jin Yong
Published: March 2013

The time-dependent parameters correction model related to shear capability of reinforced concrete (RC) component was analyzed and established on the basis of present time-varying model of resistance parameters of RC bridge. During the analysis, the time-variation of concrete strength, reinforced area, yield strength and cross-section geometric feature of reinforced concrete structure were considered in this paper. Also, the correction factor of comprehensive bearing capacity provided by both concrete and stirrup, the model comprehensive correction factor and the time-dependent comprehensive correction factor were introduced during the analysis. After calculating probability distribution and variation coefficient of parameters and correction factors mentioned above, through the Monte Carlo simulation method, the starting time of reinforcement corrosion, the reinforced effective area and the shear capacity were calculated time-dependently. Eventually a calculation example was presented in detail based on a real bridge engineering which proves the feasibility and applicability of the method mentioned in this article and can be referenced by other similar engineering.
Analysis of Traveling Wave Effect on Half-Through CFST Arch Bridge by Large Mass Method
Authors: Ma Jun , Li Yan
Published: March 2013

For long span arch bridges, the traveling wave effect is an important aspect on seismic response of structure which cannot ignore. The Big Mass Method was used to analyze the seismic response of a half-through CFST arch bridge under both uniform and non-uniform excitations. The results showed that the traveling wave effect caused by non-uniform excitation led to more obvious seismic response in both internal forces and displacements. The skewback section was most dangerous. The waveform of internal forces caused by non-uniform excitation was quite similar to that caused by uniform excitation, but the amplitude of the latter is bigger than the former. It can conclude that the traveling wave effect would cause the unsynchronized vibration to the structure elements which led to the lager responses.
Buffeting Reliability Analysis of Long Span Concrete-Filled Steel Tube Arch Bridge during Construction Stage
Authors: Li Yan , Ma Jun , Sheng Hong Fei , Yin Li Hui , Wang Li , Wang Zheng Jun
Published: March 2013

In construction stage, a large buffeting response would endanger construction safety and quality for a long span concrete-filled steel tube (CFST) arch bridge. Developing the study on buffeting security is indispensable to CFST arch bridge in construction stage. Combining random vibration analysis of structure with modern probability theory, taking an actual large span CFST arch bridge as example, dynamic reliability of buffeting responses research and analysis is developed, which is based on the buffeting analysis on time domain at the longest cantilever construction stage. The paper gives quantitative valuation on wind-vibration safety performance of the bridge in construction phase and offers a new thought and reference for homologous project.
Cartilage Regeneration and the Role of Vibrational Spectroscopy in Future Joint Arthroplasty
Authors: Pezzotti Giuseppe , Sugano Nobuhiko
Published: March 2013

The most advanced options nowadays available in joint arthroplasty rely on the application to diseased joints of human-made bearing surfaces consisting of microstructurally engineered polyethylene and ceramics as substitutes for the damaged joint cartilage and, partly, for bone. However, it is progressively becoming clear that, whatever superior the biomaterial designed for this purpose, owing to the quite severe structural requirements for human joints, including high contact stresses and aggressive environment at the load-bearing surface, it will have a necessarily limited service lifetime. Giving a quite critical but fundamentally true statement, one could say that, so far, no single product has yet been capable to meet all such severe requirements. Moreover, it is not clear if such a perfect biomaterial will ever exist. This is the main reason for pursuing repair (rather than replacement) of damaged cartilage. In this paper, we inquire about the present status and expected progress in healing osteoarthritis (OA) of chronically damaged joints, and surmise that such innovative procedures could sometime, in the near future, replace the current joint arthroplasty procedures, thus avoiding the unavoidably intrusive surgery associated with nowadays total joint replacements. After reviewing the state of art in the new field of joint cartilage healing, we shall stress the potential importance of vibrational spectroscopy both in diagnostics and in accelerating discoveries through the future developments of therapeutic approaches to cartilage diseases.
The Contribution of Natural Hydroxyapatite to the Development of Bone Substitutes
Authors: Lombardi Mariangela , Palmero Paola , Haberko Krzysztof , Pyda Waldemar , Montanaro Laura
Published: March 2013

Several hydroxyapatite (HAp) synthesis routes, such as solid state reactions, hydrothermal methods, wet procedures have been widely investigated. At the same time, in the last years many alternative methods to produce HAp, exploiting fish, bovine or pig bones, have been developed; among them the most used are thermal processes as well as subcritical water or alkaline hydrothermal routes.
This paper deals with a natural HAp nanopowder extracted from pig bones by a treatment with hot NaOH solution. It was demonstrated that the decomposition phenomena were avoided when the extracted HAp powder was calcined in CO2 atmosphere or by inducing the formation of CaO at 700 °C and then eliminating it through a washing procedure.
The washed HAp was then exploited for producing macroporous components having controlled porosity features in terms of pore shape, size and volume percentage. For this aim, a combination of gelcasting and sacrificial template methods was applied as forming procedure, using agar as natural gelling agent and polyethylene (PE) spheres as pore former.
AP40 Bioactive Glass Ceramic by Sol-Gel Synthesis: In Vitro Dissolution and Cell-Mediated Bioresorption
Authors: Cacciotti Ilaria , Lehmann Giorgia , Camaioni Antonella , Bianco Alessandra
Published: March 2013

In this work, the sol-gel synthesis of AP40 bioactive glass system was reported. The obtained powder was fully characterised in terms of microstructure, composition and thermal behaviour by X-ray diffraction (XRD) measurements, Fourier transform infrared (FT-IR) spectroscopy, thermogravimetry and differential thermal analysis (TG-DTA).In vitrodissolution tests were performed in order to assess the degradation behaviour of sol-gel derived AP40 samples thermally treated at different temperatures. Finally, preliminary results on cytocompatibility are reported, based on bioresorption activity of human peripheral blood monocytes differentiated into osteoclasts on sintered disks.
Mechanical Spectroscopy Examination of Human Dentin
Authors: Amadori Stefano , Bonetti E. , Cappelloni Ilaria , Montanari Roberto
Published: March 2013

This work describes the anelastic behaviour of human dentin in the temperature range from 100 K to 673 K. Human molars, extracted from individuals (males 55-70 years old) as part of their dental treatment, were cut to obtain bar-shaped samples for mechanical spectroscopy (MS) experiments. The results are presented and discussed in two parts referring to experiments above and below room temperature.
Optimisation of Crane Mechanisms – Selected Problems
Authors: Chwastek Stefan
Published: March 2013

Design of state-of-the art crane mechanisms involves a multi-stage and multi-criterial optimization. Depending on the specificity and intended use of the machine, the optimal structure and dimensions of its mechanisms are sought as well as optimal algorithms for drive control and regulation, which requires the application of optimization criteria. It appears, however, that the approach relying on the minimum of a specifically formulated quadratic functional enables the selection of optimal geometric parameters of the mechanism and, besides, proves effective as the method of drive control. Furthermore, the geometric parameters of the mechanism can be optimized for its entire working range. Simplicity, universality and efficiency of the method are demonstrated on the example of a slewing one-link jib crane system. The search for the optimal control strategy of drive mechanisms is illustrated in the study that investigates an asymmetrically loaded platform suspended on ropes and people moving with respect to it during the hoisting phase. I. Parametric optimization of slewing mechanisms in one-link crane systems
Analyzing the Response of a Temperature Modulated Tin-Oxide Gas Sensor Using Local Linear Neuro-Fuzzy Model for Gas Detection
Authors: Hosseini-Golgoo Seyed Mohsen , Bozorgi H. , Saberkari A. , Rahbarpour S.
Published: March 2013

A resistive gas sensor (RGS) under temperature modulation regime is considered as a system for gas detection. Five target gases including Methanol, Ethanol, 2-Propanol, 1-Butanol, and Hydrogen each at 11 concentration levels, were selected for diagnosis using a single commercial gas sensor. For modulating the sensor, a staircase containing five voltage steps each with 20s plateau is applied to micro-heater of the sensor. This, in turn, alters both the temperature and the resistance profiles of the sensing layer which are considered as the input and the output of the defined system, respectively. In this way, five systems corresponding to five steps of the system input can be distinguished. Next, each system under the influence of the examined target gases is modeled with neuro-fuzzy network. Local linear model tree (LOLIMOT) used as learning algorithm of the systems and weights of the trained networks utilized as the features of the sensor in presence of target gas. Mapping these feature vectors using linear discriminant analysis showed successful classification of all target gases.
Photocatalytic Characteristics of Titania Thin Film Prepared by Micro Arc Oxidation
Authors: Oh Han Jun , Lee Jong Ho , Chi Choong Soo
Published: March 2013

Anodic titania film was synthesized by electrochemical micro plasma oxidation method in H2SO4/NH4NO3 electrolyte, and electrochemical anodizing was carried out at various electrolyte temperatures. The photocatalytic properties and surface characteristics of anodic titania film were investigated. For anodic titania film synthesized at higher electrolyte temperature, the specific surface area of anodic film and the anatase crystalline phase gradually increased. The anodic titania film fabricated in high temperature electrolyte showed not only a slight red shift related to increasing the anatase phase ratio but also a high efficiency of dye degradation.
H2S Sensing Properties of Added Copper Oxide in WO3
Authors: Nowrouzi Rasoul , Astaraei Fatemeh Razi , Kashani Shima , Zad Azam Iraji
Published: March 2013

We study Hydrogen sulfide gas detection properties of pure and 1% copper oxide added WO3 thin films. The spin coated deposits on alumina substrates were annealed at 500 C for 1 hour in order to improve the crystallinity of the films. The sensitivity of pure tungsten oxide is poor even at temperatures of about 100 C but the doped samples exhibit good response to H2S gas. Our data show sensitivity of about 1500 in 10 ppm diluted gas in air at 100 C. The films are sensitive to the gas even at 250 ppb (sensitivity about 2) H2S concentration at 100 C but with rather long recovery time. Crystal structure, morphology and chemical composition of samples were studied by X-Ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses. We suggest that Cu2O dopants dissociate H2S molecules and spillover of the hydrogen atoms onto the cracked WO3 surface. The reaction of dissociated H2S with adsorbed oxygen is the main reason for reduction of resistivity.
Nanostructured Membranes for MEMS Energy Harvester
Authors: Mousselmal H.D. , Remaki B. , Malhaire C. , Petit L.
Published: March 2013

The development of embedded systems and autonomous microsystems requires significant progress in the research of MEMS energy converters. Converting mechanical vibrations into electricity is an efficient way to collect environmental energy by using MEMS. Our contribution to this hot topic is based on the study of piezoelectric converters on silicon membranes. Due to the nature of the energy sources such as motorized machines, miniaturized devices working at low frequencies (few hundred hertz) with efficient coupling coefficient are needed and make essential the emergence of innovative solutions. In this work we propose an improved approach based on the insertion of nanostructured porous zones in circular monocrystalline silicon membranes used as resonating structures of piezoelectric converters. We have shown (in previous work) that nanostructured porous silicon exhibits an unexpected low rigidity due to the disordered interconnections of the crystallites in the porous zones (the Young modulus is divided by a factor of 10 for porosities around 50%). Using such porous silicon properties, ring-shaped nanostructured zones allowing the creation of low rigidity membranes combined with central seismic masses were realized and tested. Interesting potentialities for the development of high quality factor devices at low resonant frequencies have been then demonstrated. The effect of the position, the shape and the size of the nanostructured zones on the resonant frequency and the quality factor of the membrane were experimentally investigated. Complementary numerical simulations were performed using ANSYS software on same modelled structures. Keywords: MEMS on silicon, piezoelectric micro generator, porous silicon, self-powered microsystem
Characteristics of Laser-Generated Visco-Elastic Rayleigh Waves
Authors: Han Qing Bang , Li Jian , Wang Hao , Zhu Chang Ping
Published: March 2013

This paper reports on a study of the propagation characteristics of visco-elastic, Rayleigh waves induced by laser ultrasonics in half space structures. Beginning with the Kelvin model, the characterization equation and the normal displacement of visco-elastic Rayleigh waves in are derived and the influence of the visco-elastic modulus on dispersion and attenuation are discussed. The transient response of a visco-elastic Rayleigh wave is also simulated by means of Laplace and Hankel inversion transforms. The papers results and conclusions will provide insights and guidance for estimating visco-elastic parameters
A Novel Fiber-Optic Mass Flow Sensor
Authors: Dakić Bojan M. , Bajić Jovan S. , Stupar Dragan Z. , Slankamenac Miloš P. , Živanov Miloš B.
Published: March 2013

In this paper a novel fiber-optic mass flow sensor based on coriolis force is presented. As sensing elements two fiber-optic curvature sensors mounted on elastic rubber tube are used. Rubber tube with sensing elements is excited by stepper motor. Produced system has the option of varying angle and speed of excitation. The bending of the fibers at the sensitive zone on curvature sensor changes the intensity of light traveling through the optical fiber. Curvature sensors are attached to the rubber tube so that they can measure phase difference produced by coriolis force. Mass flow rate is obtained by digital signal processing technique for phase difference detection.
Direct Surface Relief Formation in Polymer Films
Authors: Gerbreders Andrejs , Kolobjonoks Vadims , Shimane Oksana , Teteris Janis
Published: March 2013

Due to active development of nanoelectronics, the studies of methods of nanorelief surface formation in different materials, in particular polymers are very important. Organic polymer films in consequence of their dielectric and optical properties have been used as basis of these devices. In this paper, the possibility of UV optical record and electron beam lithography in different type of polymeric films was studied. Mechanisms of molecular structure changes: photoisomerization, destruction, cross-linking and oxidation have been discussed. The results of UV illumination of polyurethanes, polyacrylates, and some block-copolymers were described. The element analysis of polybutadiene block copolymer was performed before and after UV illumination, and the changes in optical transmission spectra of the polymer film were measured. The resolution of electron beam lithography on polymeric films also was studied.
Comparative Studies of Dielectric Properties of Ca0.25Cu0.75TiO3 Ceramics Produced by Mechanochemical Synthesis and in the Way of High-Temperature Treatment
Authors: Dulian Piotr , Bąk Wojciech , Wieczorek-Ciurowa Krystyna , Kajtoch Czesław
Published: March 2013

The paper presents a comparative study of Ca0.25Cu0.75TiO3 (CCTO) electrical properties produced by two methods - mechanochemical synthesis and high temperature treatment. Products differ significantly in terms of grain morphology and the degree of defects in structure. This is the reason why electrical properties are different.
Structural Health Monitoring of Solid Rocket Motors' Propellant Using Polymer Optical Fibers
Authors: Riziotis Christos , Eineder Ludwig , Bancallari Luca , Tussiwand Giuseppe
Published: March 2013

Polymer Optical Fibers are proposed for the monitoring of structural health condition of energetic materials in solid rocket motors. This photonic solution provides the necessary electromagnetic immunity and inherent electrical safety characteristics in the highly explosive environment of SRM's propellant. Furthermore the use of POF's intrinsic elasticity in contrast to silica fibers makes possible the monitoring of excessive strains apparent in the behavior of the energetic propellant. Both jacketed and unjacketed fibers were employed demonstrating excellent strain transfer characteristics able to monitor consistently propellant's behavior under strain.
Developing a Transducer Based on Localized Surface Plasmon Resonance (LSPR) of Gold Nanostructures for Nanobiosensor Applications
Authors: Turhan Adil B. , Ataman Demet , Cakmakyapan Semih , Mutlu Mehmet , Ozbay Ekmel
Published: March 2013

In this work, we report the nanofabrication, optical characterization, and electromagnetic modeling of various nanostructure arrays for localized surface plasmon resonance (LSPR) based biosensing studies. Comparison of the experimental results and simulation outputs of various nanostructure arrays was made and a good correspondence was achieved.
Plasma Treatment as a Way of Increasing the Selectivity of Carbon Nanotube Networks for Organic Vapor Sensing Elements
Authors: Olejnik Robert , Slobodian Petr , Cvelbar Uroš , Riha Pavel , Sáha Petr
Published: March 2013

Multi-walled carbon nanotubes networks (MWCNTs) were used as a layer for organic vapor detection. The sensor detects volatile organic compounds (VOC). The gas sensing by MWCNTs is measured by means of macroscopic electrical resistance. The selected solvents had different polarities and volume fractions of saturated vapors. The electrical resistance of MWCNTs increases when exposed to organic solvent vapors, and a reversible reaction is observed when the MWCNT is removed from the vapors. The MWCNTs were modified by means of plasma treatment. For modifications RF plasma in O2 at 50 Pa and an afterglow configuration were used. The modified MWCNTs show an increase in sensitivity caused by creating carboxylic groups on the surface of the carbon nanotubes. It leads, for example, to enhancement of the sensitivity from usual 30 % for heptane at RT to more than 200% after plasma treatment in O2 for 10s.
Optimal Group Configurations of Fibre Materials Based on Inclusion Modelling
Authors: Cardew George , Noroozi Siamak , Vinney John E. , Dupac Mihai
Published: March 2013

The use of high performance composites is becoming increasingly common in safety critical components. The key driver behind this research is the need to develop a better understanding of through thickness stresses where fibres and matrix are not uniformly distributed throughout the thickness. Classical distribution of composite is not always possible due to problems associated with manufacturing processes. Poor fibre distribution through the thickness affects the through thickness properties and can compromise the structural integrity. This paper presents a semi-analytical tool that can be used for modelling of fibre group optimisation. It can be used for analysis at both microscopic (fibre resin interactions) and macroscopic (composite laminate) levels. At each level the components reactions to externally applied load have been investigated through its load transfer mechanisms. The effects of anisotropy, edge distance and pitch between fibres, numbers of rows and finally dissimilar fibre materials and fibre cross section have been considered.
Microfluidic Gas Sensing with Living Microbial Cells Confined in a Microaquarium
Authors: Ozasa Kazunari , Lee Jee Soo , Song Simon , Hara Masahiko , Maeda Mizuo
Published: March 2013

We investigated on-chip cytotoxicity gas sensing using the bacterial chemotaxis of Euglena confined in a microaquarium. The sensor chip made from PDMS had one microaquarium and two microfluidic channels passing aside of the microaquarium. The chemotactic microbial cells were confined in the microaquarium, whereas two gases (one sample and one reference) flowed in the two isolated microchannels. Gas molecules move from the microchannels into the microaquarium by permeation through porous PDMS wall, and dissolve into the water in the microaquarium, where Euglena cells are swimming. The chemotactic movements of Euglena were observed with an optical microscope and measured as traces in real time. By injecting CO2 and air into each microchannel separately, the Euglena cells in the microaquarium moved to air side, escaping from CO2. This observation showed that the concentration gradient of CO2 was produced in the water in the microaquarium. The CO2-avoiding movement of Euglena was increased largely at a CO2 concentration of 40%, and then moderately increased above 60%. Some Euglena cells stopped swimming at the air side of the microaquarium and remained there even after CO2 has been removed, which can be used as the indicator of CO2 history.
Oxhydroelectric Effect in Bi-Distilled Water
Authors: Germano Roberto , del Giudice Emilio , de Ninno A. , Elia Vittorio , Hison Cornelia , Napoli Elena , Tontodonato Valentino , Tuccinardi F.P. , Vitiello G.
Published: March 2013

Oxhydroelectric Effect, that is the extraction of electricity from an aqueous electrolytic solution by twin Platinum (Pt) electrodes, mediated by oxygen molecules, has been detected for the first time in bi-distilled water (electric conductivity of 1.2 microSiemens/cm). A dc power of the order of tenths of microW, lasting for many hours, was measured through a resistor (47 kOhm) connected to twin Pt electrodes immersed into bi-distilled water, after the addition of some pieces of Nafion® in one semi-cell and of a very small amount of hydrogen peroxide (H2O2) - as a source of oxygen - in both semi-cells.
Investigation of Strain Sensing Properties of Polyester/Magnetite Composite Materials
Authors: Karagiovanaki Sotiria , Zoumpoulakis Loukas
Published: March 2013

The aim of this work is to investigate the strain sensing properties of polyester/magnetite composite materials of different contents 5, 10, 15, 20% w/w. Specifically, we manufactured magnetic composite materials with a polyester matrix (thermosetting polymer) and nanoparticles of magnetite (Fe3O4) as additives, processed by molding technique. For these composites we used two different magnetite powders of grain sizes a) 20-30nm (premade from Alfa Aesar) and b) <1 μm (powder made by the co-precipitation method in our laboratory). The specimens were subjected into tensile stress in order to observe the alternation of Reluctance induced by strain. The sensing probe is consisted of an electromagnet and a Hall sensor (magnetic flux density sensor). The electromagnets coil is supplied by direct current (DC) causing magnetic flux to circulate the core of the specimen. The results from the tensile stress experiments show that the magnetic flux density B decreases analogous to the Strain.
Characterization of Amorphous, Magnetic Fe-Si-B Ribbons
Authors: Varouti Eirini
Published: March 2013

The aim of this study is to contribute to a better understanding of the properties, structure and crystallization process of the amorphous Fe-based ribbon with the following chemical compositions: Fe80SixB20-x (x=5,6,8) and Fe75Si15B10. Thermal analysis, including Differential Scanning Calorimetry and Magnetic-Thermogravimetric Analysis, were used to shed light in the thermal stability and structural changes taking place during the transformation from the amorphous state to the crystalline state. The arising microstructure was observed via X-ray diffraction. Finally, Magnetic Barkhausen Noise measurements took place so as conclusions to be derived relevant to the dependence between the parameters of the Magnetic Barkhausen Noise and the chemical composition of the amorphous ribbons.
Stress Dependence of Switching Field during the Devitrification of Finemet-Based Magnetic Microwires
Authors: Olivera J. , Varga Rastislav , Anaya J. , Zhukov Arcady
Published: March 2013

We have studied the influence of the thermal treatment on the stress dependence of the switching field during the devitrification of amorphous Fe73.5Cu1Nb3Si11.5B11 microwires. The non-destructive test (NDT) method based on the magnetization reversal of ferromagnetic materials is sensible to changes in microstructural characteristics and the stress state of the material. The stress dependence has been explained considering the magnetoelastic contribution to the switching mechanism which is modified applying the tensile stresses and changing the magnetostriction constant and strength of the internal stresses distribution through thermal treatments. We show that by properly setting a frequency during the measurement and adequate treatment of the sample, it is possible to vary the sensitivity, magnitude and stress dependence of the sample. Keywords: Magnetic bistability, glass-coated microwires, switching field, stress sensor
Evaluation of the Polarization State of Integrated Piezoelectric Sensors and Actuators Using the Thermal Wave Method
Authors: Eydam Agnes , Suchaneck Gunnar , Gerlach Gerald
Published: March 2013

In this work, we investigate the polarization state of a Low-Temperature-Cofired-Ceramics (LTCC)/PZT sensor-actuator and a Macro-Fiber Composite (MFC) actuator. An analytical solution for a 1-D thermal problem was derived for an embedded piezoelectric plate. Transient thermal analysis of the more complicated MFC actuator was performed using finite element modelling. At modulation frequencies below 10 Hz both modules are well described by a harmonically heated piezoelectric plate exhibiting heat losses to the environment.
Full Factorial Design to Study Material Parameters of Magnetorheological Fluid
Authors: Ismail Izwan , Mazlan Saiful Amri , Aqida Syarifah Nur , Olabi A.G.
Published: March 2013

This paper presents the effects of magnetorheological (MR) fluid parameters, bidisperse ratio, carrier fluid viscosity and particle volume fraction, on its mechanical behaviour using statistical investigation. Silicone oil-based MR fluid samples were compressed using universal testing machine (UTM) in a vertical direction. A set of eight experiments was designed by Design Expert 7 software in which was conducted at two levels for each factor. Stress-strain curves that obtained from the compression test were then analysed by testXpert analyser software. The responses in terms of maximum stresses at 0.75 of strain were extracted from the curves. The result indicated that a combination of high bidisperse ratio and particle volume fraction, and a low carrier fluid viscosity could produce a high compressive stress. The findings are important to be considered in designing squeeze mode MR fluid actuators.
Induction of Nuclear Reactions through Piezoelectrics and other Means
Authors: Srivastava Yogendra N. , Mencarelli E. , Illic L. Fano , Servoli L. , Fiandrini E. , Widom Allan , Swain J.
Published: March 2013

In this paper we shall rst describe low energy nuclear transmutation theory [LENT]and then apply it to describe how a \smart" material such as a piezoelectric rock when crushedcan induce nuclear reactions with production of neutrons which have been observed. An experimentalprogram being set up at Perugia for realizing LENT is also briey noted.