bluuebunny/crossref_metadata_2025 huggingface dataset:
Protección colectiva contra caídas para trabajadores de la construcción
Authors: Sulowski A. C.
Published: April 2014

﻿Las normas de seguridad en la construcción requieren de protección para los trabajadores contra las caídas desde altura. Los Sistemas de Protección contra Caídas (FPS, por sus siglas en inglés) colectivos, en la mayoría de los casos, permiten que los trabajadores se muevan libremente sin usar un equipo de protección contra caídas individual. Los sistemas colectivos de prevención de caídas son preferibles a los sistemas de detención de caídas, estos últimos se emplean sólo si la prevención de las caídas no es factible. La detención de una caída siempre lleva consigo un riesgo residual de lesiones en la víctima accidentada. Los sistemas colectivos de detención de caídas se emplean principalmente en la construcción de torres de electricidad o telecomunicaciones. El objetivo de este trabajo ha sido la revisión de los sistemas colectivos de protección contra caídas empleados en la industria de la construcción.
La herencia científica del Instituto Eduardo Torroja en Bilbao (1960-1980)
Authors: Bilbao L.
Published: April 2014

A través de este análisis, hemos tratado de valorar y comprender tanto la influencia que suscitó el IETcc en el progreso científico bilbaíno fundamentalmente durante los años 60 y los años 70, así como la decidida pretensión de la élite financiera e industrial local de hacer entonces de Bilbao la gran metrópoli del norte, es decir, la capital económica de aquella España, tomando para ello como modelo, entre otras metrópolis, a la ciudad americana de las finanzas, Nueva York, y a la de la industria, Pittsburgh. Se han estudiado los instrumentos de los que se valieron para que así fuera: desde organismos de investigación, exposición e información que originarían un anhelado progreso científico, así como las líneas para reproducir la fascinante vía americana.
Product Patterns to Support Knowledge Acquisition Management
Authors: Vásquez-Bravo Diana-Marcela , Sánchez-Segura Maria-Isabel , Medina-Domínguez Fuensanta , Amescua Antonio
Published: April 2014

The knowledge elicitation process allows for the acquiring and transferring of knowledge. Actually, this process presents difficulties when selecting the appropriate elicitation technique. This chapter presents a classification of the elicitation techniques used in software engineering and the relationship between the elicitation techniques and some elements of knowledge management such as assets knowledge, epistemological dimension of knowledge and the knowledge creation phases. This classification provides a guideline to select a technique or a set of techniques for knowledge elicitation based on phases of Nonaka's model. Additionally, the chapter presents the use of product patterns in knowledge elicitation, and defines a product pattern as formal representation mechanism for each of the knowledge assets defined and presented in this chapter.
Open Source vs. Proprietary Collaborative Virtual Learning Environments
Authors: Mavridis Apostolos , Konstantinidis Andreas , Tsiatsos Thrasyvoulos
Published: April 2014

This chapter is an evaluation of the efficiency of 3D Collaborative Virtual Learning Environments to facilitate the implementation of collaborative learning activities. Firstly, there is a presentation of the state of the art regarding open source as well as proprietary platforms. Afterwards, the use of a case study reveals issues concerning the suitability of open source Collaborative Virtual Learning Environments, rationalizing the choice of executing a collaborative learning scenario in Second Life. The specific scenario is then presented culminating in evaluation results related to the appropriateness of Second Life with regards to its technical and pedagogical affordances. Finally, students' suggestions and reactions towards such a novel didactical approach are discussed.
Current Trends and Developments, Future Requirements, and Predictions for Computer Mediated Communications and E-Collaboration
Authors: Keary Alfie , Redfern Sam , Walsh Paul
Published: April 2014

This chapter provides a revision and update to the authors' original 2012 research that discussed fifteen semi-structured interviews carried out with international industry experts and thought leaders within the computer mediated communications and e-collaboration field. The original interviews focused on 5, 10, and 15-year time frames, and sought to elicit predictions on the components and services of future platforms, as well as their likely impact on business processes and value chains. Affinity Diagramming/KJ Analysis techniques on the original interview transcripts exposed a number of key tenets that are now revisited, discussed in a current context, revised and updated in this chapter. Following a similar structure to the 2012 paper, the authors discuss the origins of the field, main providers and platforms, related software development technologies, W3C standards, video conferencing, telepresence, cloud computing and Enterprise 2.0. The authors provide a synopsis of the original interviews and have updated their conclusions and findings in light of most recent research and developments. With reference to future requirements, they have also updated their discussions on a next generation architecture proposal/model with additional insights from the authors' research work and that of others in the computer mediated communication and e-collaboration field.
The Culture on the Palm of Your Hand
Authors: Palumbo Federica , Dominici Gandolfo , Basile Gianpaolo
Published: April 2014

The increased usage of mobile apps has a great potential for the tourism industry. Through the use of mobile apps, web portals and social media may allow a fast and wide diffusion of awareness for museum and attract a large number of visitors, thus increasing the value of their image, with moderate investments. The aim of this chapter is to identify the key factors as antecedents of customer satisfaction for the design of a mobile app for a museum. To this aim, the authors use the Kano model that allows categorizing service attributes according to how they are perceived by customers and estimating their impact on customer satisfaction. This model is adopted in order to identify express and latent needs of cultural tourists and to design a mobile app for museum according to their perceptions and expectations. To apply the Kano model, the authors used qualitative data collected through 300 questionnaires administered to tourists visiting the Sicilian cities of Palermo and Trapani over a period of 3 months (October- December 2012). The results of this analysis can be relevant for museum and public managers to plan strategic and operative activities, for researchers in the field of touristic marketing, for application developers, and for all those concerned with touristic and cultural heritage issues.
Reconciling Social Media with Luxury Fashion Brands
Authors: Ozuem Wilson , Tan Kerri
Published: April 2014

Modern developments in communication media are creating new networks of information diffusion which are profoundly altering the way in which people can construct shared ‘realities'. Internet along with its prototypical subsets, notably social media, is enabling the emergence of new mechanism of human association which are shaped by – yet also shape – the development of this new medium of communication. This chapter integrates social media theory and luxury fashion brand theory arguments to examine the knowledge benefits that this cultural transformation provides to the development of a marketing communications programme. The authors argue that the key to providing an effective marketing communication programme is understanding and responding to customer expectations through the integration of social media platforms and traditional marketing communications media.
Electrochemical Sensor for Monitoring RedOx Potential of Molten Salts
Authors: Alekseev Pavel , Grishanin Eugene , Shimkevich Alexander
Published: April 2014

A precise monitoring of reductionoxidation (RedOx) potential is necessary for using molten salts as fuel compositions and coolants in molten-salt reactors as well as for pyrochemical processing of a spent fuel. So, low over-potentials (~10 mV) are required for rigorously selective extraction of impurities out of the molten salt due to a permanent diffusive cathode polarization in galvanic cell. At the same time, a weak identification of cationic disproportionation (Mk+ Ml+) of metal impurities in liquid salts reflects the common defect of all known internal monitoring tools using salt as a sensor: realizing high over-potential and thereby strong polarization of the cathode. It leads to appreciable energy deformation of allowed electron states in the molten salt near the electrodes so that metal components of the basic salt are extracted out of the salt solution together with the selected impurity. Obviously, such the kinetic monitoring of RedOx potential cannot be a precise method since there is impossible eliminating the uncertain polarizing cathode effects in the galvanic cell with the molten salt as an electrolyte. Therefore a monitoring of the RedOx potential of liquid salts by means of an external potentiometer is necessary. This method is based upon the using of a gauge with Na+βAl2O3 electrolyte as a solid membrane with unipolar sodium conductivity assigned for monitoring a thermodynamic activity, , of neutral sodium atoms (Na0) in the molten salt. The principle of operation of such the gauge is based on the e.m.f. method. A measuring electrode, Pb [N (a thin layer of liquid lead on the solid electrolyte), directly contacts with the molten salt, easily exchanges by dissolved sodium atoms, and corrosive protects the solid electrolyte. The e.m.f., E, of this electrode is defined relatively a reference electrode (liquid sodium) located on the other side of solid electrolyte, Na+βAl2O3, in the four-layer galvanic cell: NaNa+βAl2O3Pb [Nsalt [], by equation, E = (RT/F) ln, where R is the universal gas constant, T is Kelvin temperature, F is Faraday constant.
Fabrication of Infrared Detector Based on of Polyaniline/Polyvinylidene Fluoride Blend Films and their Pyroelectric Measurement
Authors: El-Shaer A.M. , Aboulseoud A.K. , Soliman M. , Ebrahim Sh.
Published: April 2014

Infrared detection based on polymeric materials is continuously developed in order to be cheap and easy to processing and also having high pyroelectric coefficient to convert heat to electrical signal. PANI/DBSA was blended with polyvinylidene fluoride (PVDF) with different weight ratios to improve pyroelectric coefficient and electrical conductivity of PVDF. The temperature dependence of the electrical conductivity is measured in the range of 20-100 °C It was found that the pyroelectric coefficient increased from 1.5×10-8 C/m2 °C for pristine PVDF to 2.61×10-5 C/m2 °C at 25 wt.% PANI at 30 °C. The infrared detector circuit connected to the gate of a voltage follower JFET with high input impedance was designed to convert the high output impedance of the sensor into the output resistance. The output from the sensor and JFET is amplified in two stages of operational amplifier with high voltage gain with low noise.
The Fabrication and Characterization of Niobium-Doped Titania Ceramic
Authors: Wu Ming Wei , Chen Yan Chi , Tsao Chung Ya , Lin Chien Chi
Published: April 2014

Transparent conductive oxide (TCO) films have been widely used in various optoelectronic devices as the transparent conductive electrode. Niobium-doped titania (TNO) films were recently found to be highly transparent and conductive and thus could be a potential substitute for tin-doped indium oxide (ITO) films. For the preparation of TCO films, magnetron sputtering is a versatile method due to its high deposition rate, feasibility for large-area deposition, and other advantages. The quality of the sputtering target has been found to obviously affect the performances of the films. However, the fabrication and the properties of sputtering targets have rarely been examined. Thus, the purpose of this study was to prepare and characterize TNO ceramic for application as a TNO sputtering target.
Sub-micrometer TiO2 and Nb2O5 powders were used to formulate the ceramic slurry with a dispersant and a binder. The ceramic slurry was then spray-dried to form spray-dried granules. TNO green compact was produced by uniaxial compacting of the spray-dried granules. After 1200°C sintering in air, the sintered density of the TNO ceramic was 100%. The grain size was only 2.8μm. Moreover, after 1200°C sintering, the TNO ceramic was fully rutile phase, as verified by XRD. Nb2O5 diffused and dissolved into the titania. Furthermore, the dopant of Nb greatly decreased the resistivity of titania from 108Ωcm to 90Ωcm, though the resistivities of the TNO ceramics were higher than those of TNO films reported in the literature.
Analysis of Nanoparticle-Based Surface Plasmon Resonance Fiber Optic Sensor
Authors: Ciprian Dalibor , Hlubina Petr
Published: April 2014

Theoretical analysis of surface plasmon resonance ber optic sensor based on a core-shell nanoparticle layer is presented. The sensing structure consists of a standard step-indexmultimode optical ber whose bare fused silica core is coated by Ag core-shell nanoparticlemonolayer. Its optical constants were obtained using e ective media (Maxwell-Garnett) theory.Theoretical model based on thin- lm optics approach is used to compute the normalized powertransfer through the sensing part of the ber in spectral domain. The computed results areused to obtain the sensitivity and detection accuracy of the sensing scheme with respect tothe concentration of analyte components. The inuence of nanoparticle geometry on the sensorperformance is discussed.
New Indigo/Nanocarbons Hybrid Material as Chemical Filter for the Enhancement of Gas Sensor Selectivity towards Nitrogen Dioxide
Authors: Brunet J. , Pauly A. , Dubois M. , Varenne C. , Guerin K. , Ndiaye A.
Published: April 2014

A new hybrid material performed by the immobilization of indigo particles on nanocarbonaceous matrix has been developed, characterized and implemented with chemoresistors. If phthalocyanine-based chemoresistors provide a high sensitivity, a low threshold of detection and a partial selectivity towards oxidizing pollutants, indigo/nanocarbons hybrid material acts as a selective ozone filter from air sample and so strongly enhances the sensor selectivity towards nitrogen dioxide. The functionalization, highlighted by scanning electron microscopy, X-ray diffraction and thermogravimetric analysis, occurs in a non-covalent way and proceeds through pi-stacking interactions. With filtering yields higher than 99.5% for ozone and less than 5% for nitrogen dioxide, indigo adsorbed onto multi-wall carbon nanotubes has been identified as the most selective filtering material while exhibiting a much greater durability than indigo or nanotubes separately. Associated to phthalocyanine-based gas sensor, the sustainable, selective and real-time monitoring of NO2 in ppb range has been successfully achieved.
Estimation of Thickness of Concrete Slab Members Using Impact Echo Method
Authors: Hong Seong Uk , Lee Yong Taeg , Kim Seung Hun , Na J.H.
Published: April 2014

Recently, the interest in maintenance and repair of existing concrete structures have increased, and it is typical to use non-destructive testing methods such as rebound hardness test or ultrasonic pulse velocity method to execute maintenance and repair of structures efficiently. Many non-destructive testing methods are being used in practice such as at construction sites, but verification for site applications are quite inadequate. Thus, this study intends to evaluate the applicability of Impact Echo Method which is one of the non-destructive testing methods using stress wave. Total of four specimens were planned and produced. The thickness of concrete slab members was estimated using I.E(OLSENs Freedom Data PC with Win.TFS Software Version 2.5.2). The estimated materials of concrete members by IE was found to be IE-1 specimen 178mm, IE-2 specimen 197mm, IE-3 specimen 191mm, and IE-4 specimen 263mm, and the error rate was found to be 4.22%~18.67% (average 9.6%), showing that they are relatively well in agreement. In this study, the experiments were executed with the objective of estimating the thickness of concrete slab members using Impact Echo Method. Through this study, the applicability of thickness estimation in concrete slab members using impact echo method could be confirmed.
Estimation of Compressive Strength of Concrete Member Using Ultrasonic Pulse Velocity Method
Authors: Lee Yong Taeg , Hong Seong Uk , Kim Seung Hun , Park J.H.
Published: April 2014

This study uses the ultrasonic pulse velocity method, one of the non-destructive testing methods that do not damage the structure, to analyze the correlation of wave velocity and compressive strength of normal strength and high strength concrete to propose an estimation formula. And a concrete member is produced to estimate the compressive strength, and provide elementary data for establishing a site-applicable standard for strength estimation formula. In order to analyze the correlation of concrete compressive strength and wave velocity, total of 144 specimens were produced per age, and six concrete members were produced for wave velocity measurement. In this study, the Ultrasonic Pulse Velocity method was used to propose a compressive strength estimation formula of normal strength and high strength concrete, which was applied to concrete members for verification, and the following conclusion was obtained. The correlation between wave velocity and compressive strength was found to be Fc=0.0952VP3.5, R2=0.82 for normal strength concrete, and Fc=0.0028VP6.1, R2=0.83 for high strength concrete. Result of comparing the estimated strength of the concrete member of the relative error rate was standard strength 18.7% on average, the high-strength 8.7%
Estimation of Compressive Strength of Recycled Aggregate High Strength Concrete Using Ultrasonic Pulse Velocity
Authors: Hong Seong Uk , Kim Seung Hun , Lee Yong Taeg
Published: April 2014

This study used the ultrasonic pulse velocity method, one of the non-destructive test methods that does not damage the building for maintenance of to-be-constructed concrete structures using recycled aggregates in order to estimate the compressive strength of high strength concrete structure using recycled coarse aggregate and provide elementary resources for technological establishment of ultrasonic pulse velocity method. 200 test pieces of high strength concrete 40, 50MPa using recycled coarse aggregate were manufactured by replacement rates (0, 30, 50, 100%) and age (1, 7, 28, 180days), and air curing was executed to measure compressive strength and wave velocity. As the result of compressive strength measurement, the one with age of 180day and design strength of 40MPa was 43.69MPa, recycled coarse aggregate replacement rate of 30% 50% 100% were 42.82, 41.22, 37.35MPa, and 50MPa was 52.50MPa, recycled coarse aggregate replacement rate of 30% 50% 100% were 49.02, 46.66, 45.30MPa, and while it could be seen that the test piece substituted with recycled aggregate was found to have lower strength than the test piece with natural aggregate only, but it still reached the design strength to a degree. The correlation of compressive strength and ultrasonic pulse velocity was found and regression analysis was conducted. The estimation formula for compressive strength of high strength concrete using recycled coarse aggregate was found to be Fc=0.069Vp4.05, R2=0.66
Influence of Microstructure on Performance of TiO2 Nanodots Film Based Biosensor Electrodes
Authors: Hammadi Mohannad Saleh , Cheng Kui , Weng Wen Jian
Published: April 2014

Electrochemical biosensors are widely applied in areas related to health monitors. Protein adsorptions on the electrode and direct electron transfer between enzymes and electrode have been recognized as key factors affecting sensor performance. In this work, TiO2 nanodots films were prepared on Ti substrate to act as electrodes of biosensors. The effect of the nanodots film microstructure on electrode performance was carried out. It was found that the performances H2O2 biosensor could be improved by tailoring TiO2 nanodots film microstructure in the electrodes. The present work could provide an alternative to obtain biosensor with high performance.
Dehydroacetic Acid Based Dioxaborine Styryl Dye: Effective Fluorescent Probe for Ammonia and Amine Detection
Authors: Shandura M.P. , Kovtun Yu.P. , Yakubovskyi V.P. , Piryatinski Yu.P. , Lutsyk P.M. , Perminov R.J. , Verbitsky A.B. , Rozhin A.
Published: April 2014

The newly synthesized dioxaborine dyes, derivatives of dehydroacetic acid, were tested for the detection of amines and ammonia. To discriminate the substance with efficient sensing parameters, series of ca. 20 dioxaborine dyes were synthesized and tested for reactivity with amines. The most promising one showed the fluorescent sensitivity to amines in the range of 1-4 ppm.
SPE of Phenols on New Amine - Based Copolymers
Authors: Sobiesiak Magdalena , Podkościelna Beata
Published: April 2014

Porous microspheres, copolymers: bis [4(2-hydroxy-3-methacryloyloxypropoxy)-phenysulfide (BES.DM) and glycidyl methacrylate (GMA) have been prepared by suspension-emulsion polymerization. The copolymer (BES.DM+GMA) including reactive epoxide rings was modified with three amines: butylenediamine (BDA), diethylenetriamine (DETA), triethylenetetramine (TETA). Next, attachment of HCO3- species to the primary amine groups took place.The prepared porous polymers were used as adsorbents in off-line SPE experiments. A mixture of phenol (PH), 2-chlorophenol (ChP), 2,4-dichlorophenol (DChP) and 2,4,6-trichlorophenol (TChP) as testing compounds was applied.Depending on the way of chemical modification, the prepared adsorbents possessed diverse sorption properties towards the testing compounds. Competition of the phenolic compounds for active sites presented on the polymer surface was observed. The most effective in water purification process were polymers possessing both amine and bicarbonate groups. The best recovery results were obtained for 2,4-dichlorophenol.
Vapour Sensitivity of InP Surface Quantum Dots
Authors: de Angelis Roberta , Casalboni Mauro , D’Amico Liliana , de Matteis Fabio , Hatami Fariba , Masselink William T. , Prosposito Paolo
Published: April 2014

We studied the effect of solvent vapours on the photoluminescent emission of self-assembled InP surface quantum dots (SQDs). Their room temperature near infrared emission undergoes a fully reversible intensity enhancement when the dots were exposed to vapours of polar solvents since polar molecules are likely to be adsorbed onto intrinsic surface states and thus reducing non radiative surface recombination. The shape and position of the emission band does not change. The observed effect is dependent on solvent type and concentration with linear law over a limited concentration range.
The Development of FeMn2O4 Gas Sensors at Room Temperature
Authors: Gaidan Ibrahim
Published: April 2014

Different ratios of MnO2 / Fe2O3, were used after being fired to form thick film gas sensors. The films were deposited on alumina substrates. The response of the sensors for a concentration range of 2500-5000 ppm increasing by a step size of 500 ppm of propanol at room temperature was investigated. The highest response was with the 75 / 25 MnO2 / Fe2O3 sensor followed by the 25 / 75 and 50 / 50 MnO2 / Fe2O3 sensors. The repeatability of the 75 / 25 mol. % MnO2 / Fe2O3 to propanol at two concentration ranges 500-3000 and 2500 - 5000 ppm increasing with a step size of 500 ppm at room temperature was reported. The X-Ray Diffraction (XRD) is used to determine the final composition of the materials after firing. The XRD results show that MnO2 reacts with Fe2O3 to form FeMn2O4 with Fe2O3 and Fe3O4..
Self-Texture Control of ZnO Films Prepared by Reactive RF Magnetron Sputtering
Authors: Novák Petr , Šutta Pavol , Netrvalová M. , Říha Jan , Medlín Rostislav
Published: April 2014

Zinc Oxide (ZnO) is a wide bandgap semiconductor material which can be successfully used for wide variety of potential applications such as biosensors or acoustic resonator devices. ZnO normally crystallizes in the wurtzite structure with c-axis (001) preferred orientation. However, for bio-sensing in liquids, it is necessary to generate a shear horizontal mode wave, where the wave displacement is within the plane of the crystal surface. For generation of such a shear horizontal wave, a-axis film textures such as the (110) or (100) is necessary. This work is focused on the preferred orientation control of ZnO film prepared by RF magnetron sputtering. It is found that preferred orientation can be controlled by substrate bias and substrate temperature during deposition without the use of expensive crystalline substrates. There are three areas of operating parameters when the structure of the ZnO films is dominated by different preferred orientation. Moreover, the film annealing was performed to enhance the film structure.
Comparison of Vapor Sensing Properties of Pristine and Hexamethylene Diamine-Treated MWCNT Networks to Primary, Secondary and Tertiary Alcohols
Authors: Benlikaya Ruhan , Slobodian Petr , Machovsky Michal
Published: April 2014

The sensing properties of pristine and hexamethylene diamine (HDA)-treated multiwall carbon nanotube networks (MWCNT-Ns) to selected primary, secondary (sec-) and tertiary (ter-) alcohols were examined by resistance measurements. It was seen that sensor responses, S (%), of MWCNT (HDA)-N to these alcohols were much higher than those of the pristine network. An increase in the S (%) values per mm Hg of both networks was observed from propanol to butanol, when their values from primary alcohols to sec-/tert-ones decreased due to the change in the interaction area of these alcohols with the MWCNT-Ns.
Switched Reluctance Motors Control
Authors: Morón Carlos , Tremps Enrique , Gomez Angel , Garcia Alfonso , Somolinos Jose Andrés
Published: April 2014

A current controlled switched reluctance motor (SRM) drive for variable speed applications with efficiency optimization is presented. A robust, modular and flexible prototyping SRM drives is proposed. It is composed of a power electronic block, a driver board, a measurement and interface board and a DSP controller board. Firing angles are computed online, the turn-on is calculated by means of the Boses rule, and the turn-off is calculated using the general theory of the optimal turn-off angle proposed by Gribble. In steady state operation, tie initial selection of firing angles is fine-tuned by means of an algorithm that minimizes the input power of the drive. A 6/4 switched reluctance motor drive prototype was tested and the experimental results show an improvement in online efficiency, a good steady-state performance and no deterioration in the dynamic response. An efficiency comparison with a commercial vector-controlled induction motor drive of the same size is also included.
A New Concept of Multimode Magnetorheological Brake Design
Authors: Hamdan L.H. , Mazlan Saiful Amri , Sarip S. , Zamzuri Hairi
Published: April 2014

This paper presents a magnetorheological (MR) brake design by using additional squeeze working mode to an existing conventional rotational shear. The MR brake was designed with consideration given to a new concept of braking mechanism with the help of magnetic simulation. Important parameters such as disc brake dimensions, clearance gap and electromagnetic coil configuration were taken into account when constructed the MR brake. Simulation results showed that the magnetic field strength was at best by having the magnetic coil beside the non-magnetic material, which was located at the end of the outer diameter. Meanwhile, the value of magnetic field was greater than when a small squeeze gap was applied. Eventually, the design will provide an opportunity to study and consequently understand on how the MR fluids react to such operating condition in order to be realized in the MR brake.
Plasma Polymerized Highly Hydrophobic Hexamethyldisiloxane Layers: Investigation on the Effect of Monomer Flow Rate Related to the Film Gas Sensing Properties
Authors: Boutamine M. , Lezzar O.C. , Bellel A. , Sahli Salah , Segui Y. , Raynaud Patrice
Published: April 2014

Hexamethyldisiloxane (HMDSO) thin films coated quartz crystal microbalance (QCM) electrodes have been characterized for the detection of volatile organic compounds (VOCs). The sensitive coatings were plasma polymerized in pure vapor of HMDSO at different flow rates. The QCM based sensors responses were found to be linearly correlated with the concentration of VOCs vapor. It was shown that it is possible to tune the chemical affinity of the sensor by changing the HMDSO flow rate. Contact angle measurements, Fourier transform infrared spectroscopy and scanning electron microscopy were used to study surface wettability, chemical composition and surface morphology of the coated QCM electrodes.
A Study on Different Types of Fiber Coils for Fiber Optic Current Sensors
Authors: Yang Lin , Frank Andreas , Wüest Robert , Gülenaltin Berkan , Lenner Miklos , Müller Georg M. , Bohnert Klaus
Published: April 2014

We consider an interferometric fiber optic current sensor with a fiber coil operated in reflection and compare three different techniques to prepare the coil: thermally annealed coils, stress-free packaging of a bare low birefringent fiber in a fused silica capillary, and coils from highly birefringent spun fiber. In particular we theoretically and experimentally investigate how the fiber retarder that generates the near left and right circular light waves in the sensing fiber must be prepared for temperature compensation of the Faraday effect in the three cases. All three methods can achieve accuracy within ±<0.2% over an extended temperature range but they considerably differ in their practical challenges.
Improved Reversibility of Liquid Lithium-Ammonia Solutions in Vacuum Tube
Authors: Kim Miae , Kim Ji Beom , Jeon Joon Hyeon
Published: April 2014

Lithium-ammonia (Li-NH3) solutions are possible to be successfully made under the vacuum condition but there still remains a problem of undergoing stable and reliable decomposition in vacuum for high-efficiency thermoelectric power generation. This paper describes a new method, which uses a tube giving pressure equilibrium between closed ends, for improving the thermoelectric conversion efficiency of Li-NH3 solutions in vacuum. Thermoelectric experimental results show that solution reaction in the tube proceeds stably and efficiently, and this potentially leads to the improved reversibility of the reaction for deriving the long-time, high-efficiency thermoelectric power.
Synthesis and Characterization of Ag Doped LaCoO3 Nanowire Sputter-Deposited Coatings as Heavy Hydrocarbon Sensors
Authors: Taguett Amine , Yazdi Mohammad Arab Pour , Sanchez Jean Baptiste , Monsifrot Eric , Briois Pascal , Berger Franck , Billard Alain
Published: April 2014

In this paper, we investigate the feasibility of La1-xAgxCoO3-α nanowires by reactive magnetron sputtering. After a short description of the experimental and hydrocarbon sensing bench devices, a first part will be dedicated to the chemical, microstructural and structural characterization (SEM, XRD,...) of the coatings. As deposited coatings are amorphous and a post heat-treatment under air at 873 K is necessary to crystallise them in the perovskite structure. Finally, the performance as dodecane-sensors of these coatings with amorphous and crystalline structures will be discussed depending on dodecane concentrations and sensitive surfaces temperature and will be compared to those of La0.40Sr0.15Ag0.45CoO3-α nanowires.
Nitrogen Dioxide and Acetone Sensors Based on Iron Oxide Nanoparticles
Authors: Ivanco Jan , Luby Stefan , Rella Roberto , Manera Maria G. , Benkovicova Monika , Jergel Matej , Siffalovic Peter , Vegso Karol , Halahovets Yurij , Majkova Eva
Published: April 2014

The Fe2O3 and CoFe2O4 nanoparticle-based Langmuir-Blodgett lms for sensingof nitrogen dioxide (NO2) and acetone vapours have been explored. Both the sensitivity of thechemiresistors and dynamic properties, such as the response/recovery time, have been probed independence of the number of nanoparticle monolayers and working temperatures. The responseof 23 at the NO2 concentration of 1 ppm has been monitored suggesting the pertinent sensitivityin the deep sub-ppm range, i.e. approaching the canine detection limit, and likewise implyingthe supposable detection of nitrate-based explosives.
The Multifunctional Composite on the Base of Carbon Nanotubes Network and its Use as a Passive Antenna and Gas Sensing Element
Authors: Olejnik Robert , Matyas Jiri , Slobodian Petr , Vlcek Karel
Published: April 2014

Carbon nanotubes in the form of entangled network can be used as a multifunctional composite material for a wide range of using. A new and perspective usage is a passive antenna and gas sensing element. The antenna works well at 1.284 GHz. The local reflection minimum is
11.48 dB. The reflection coefficient r=0.2667. The transmission power in this frequency is 93%.
Multiwall carbon nanotubes (MWCNT) network Buckypaper was made by the vacuum filtration method of MWCNT aqueous suspension. The sensitivity of multi-wall carbon nanotube (MWCNT) networks of randomly entangled pure and HNO3 oxidized nanotubes to polar and nonpolar organic vapors (ethanol, heptane), has been investigated by resistance measurements. The results demonstrate that the network electrical resistance increases when exposed to organic solvent vapors, and a reversible reaction is observed when the sample is removed from the vapors. The investigated MWCNT networks could be potentially used as sensing elements for sensitive and selective organic vapor detection.
Non-Exponential Decay Curves in Delayed Luminescence
Authors: Swain John , Srivastava Yogendra N. , Widom A.
Published: April 2014

Delayed luminescence, contrary to popular belief, never follows an exponential de-cay law and the way it falls o can be an interesting, inexpensive and non-destructive probe ofboth nonliving and living systems. We discuss the basic ideas involved, deviations from expo-nential decay, new technologies for measurement, and possible applications. For living systemsexhibiting approximately hyperbolic decays, we make a possible connection to old ideas ofSzent-Gyorgyi on charge transfer complexes in biology.
A QCM-D Study of Reduced Antibody Fragments Immobilized on Planar Gold and Gold Nanoparticle Modified Sensor Surfaces
Authors: Makaraviciute Asta , Ruzgas Tautgirdas , Ramanavicius Arunas , Ramanaviciene Almira
Published: April 2014

An immunosensor is an analytical system consisting of specific immune system molecules coupled to a signal transducer. Immunosensor sensitivity depends on the type of immunorecognition ligands used, immobilization influence on their activity and orientation on the surface. Quartz crystal microbalance with dissipation (QCM-D) was employed to investigate the immobilization of antibodies against bovine leukemia virus antigen gp51 (gp51). Disulphide bridges of antibody hinge region were reduced chemically to yield two half antibody fragments (Frag-Ab), each having a single antigen binding site and free sulfhydryl groups that were used for immobilization. Frag-Ab were immobilized on planar gold and gold nanoparticle (AuNP) modified QCM-D sensor surfaces from initial solutions of different concentrations. Higher Frag-Ab surface density values were obtained on AuNP modified surfaces at all tested antibody concentrations. Frag-Ab/gp51 specific interaction was registered and it was determined that the highest sensitivity was exhibited by Frag-Ab immobilized at the lowest surface desities on both types of investigated surfaces. Specific gp51 interaction with Frag-Ab and non-specific binding to bovine serum albumin modified surfaces were compared by employing Δf/ΔD plots, which could serve as fingerprints of different processes.
Localized Surface Plasmon Resonance Sensor of Gold Nanoplates for Detection of Boric Acid
Authors: Morsin Marlia , Salleh Muhamad Mat , Umar Akrajas Ali , Yahaya Muhammad
Published: April 2014

Localized surface plasmon resonance (LSPR) peak wavelength of nanostructures metallic materials, such as gold and silver, is very sensitive to the dielectric environment of the materials; hence widely used as sensors to detect various types of chemicals. In this study, high - yield gold nanoplates ca. 63% have been grown on the quartz substrate using the seed - mediated growth method. The grown gold nanoplates exhibit variety of shapes such as triangular, hexagonal, truncated hexagonal and flat rod. The LSPR spectrum of Au nanoplates sample has two absorption bands; centring at 543 nm and 710 nm, which are associated with transverse SPR (t-SPR) and longitudinal SPR (l-SPR) respectively. The intensities and peaks position of these two bands were found to linearly change with the concentration of boric acid solutions.
A Novel NAD+/MWNTs Nanocomposite-Based Electrochemical Biosensor for Measuring Mevalonic Acid
Authors: Palangsuntikul Rungtiva , Pakapongpan Saithip , Khownarumit Porntip , Surareungchai Werasak
Published: April 2014

A novel, simple and precise electrochemical biosensor, was developed for measuring mevalonic acid (MA) concentration, which is thought to be a good indicator of HMG-CoA reductase activity. This sensor is based on noncovalent-linking NAD+/MWNTs nanocomposite coated on a screen-printed electrode (SPE). The resulting biosensor exhibited excellent electrocatalytic activity, fast response and good stability to MA. At the NAD+/MWNTs-modified SPE, the current is linear with the concentration of MA being within a concentration range from 18.1 to 145 μM with a limit of detection down to 4.25 μM (S/N = 3), and the sensor exhibited a sensitivity of 92.2 μA/mM.
Effect of Erbium Doping on Sol-Gel Synthesized Vanadium Pentoxide and Titanium Dioxide Thin Films
Authors: Gokdemir F. Pınar , Yuzbasioglu Ece , Saatci A. Evrim , Ozdemir Orhan , Kutlu Kubilay
Published: April 2014

Comparative work of erbium doped vanadium pentoxide and titanium dioxide thin films were carried out via sol gel technique by dissolving erbium (III) nitrate pentahydrate in vanadium (V) oxoisopropoxide and titanium (IV) isopropoxide. Fourier Transform IR and thermogravimetric/differential thermal measurements were performed to find out erbium substitution. UV-Vis. spectroscopy indicated a blue shift upon Er doping in V2O5 film due to the softening of V=O bond. The similar behavior was expected in TiO2 film and the prediction shall be shown only if annealing of the film above 600°C, resulting oxygen deficiency in anatase TiO2 while Ti deficiency in rutile TiO2 film. Due to such impact of erbium on structure, granule size of the films, determined by AFM, increased yielding more space for intercalation of ion in host materials and monitored through cyclic voltammetry measurements.
Preparation of SERS Active Substrates Based on Ag/Graphene/Polymer Nanocomposites
Authors: Siljanovska Petreska Gordana , Blazevska-Gilev Jadranka , Tomovska Radmila , Fajgar R.
Published: April 2014

Nanocomposites of poly (BA/MMA) reinforced with up to 3 wt % grahene sheets were used as targets for laser ablation. The target was ablated using TEA CO2 laser with fluence of 1,00 J/cm2 and thin films of crosslinked polymer/graphene with large specific surface area were obtained. The polymer-graphene deposit was covered with silver nanoparticles by excimer laser ablation in order to prepare active substrates for Surface-Enhanced Raman Scattering (SERS). The nanocomposites were characterized by means of spectroscopy, microscopy and diffraction techniques. The SERS substrate performance was tested using Rhodamine 6G as a probe compound. Highly enhanced signal was achieved, and sensoric properties of the prepared substrates were demonstrated.
Estimation of Steel Rebar Position and Thickness in Concrete Members Using Impact Echo Method
Authors: Hong Seong Uk , Kim Seung Hun , Lee Yong Taeg
Published: April 2014

Non-destructive testing methods, unlike typical destructive testing methods that deconstruct or cut the building in case of issues such as pores, heterogeneous material, cracks or any such equivalent issues inside/outside the building. And refer to the testing methods for pores, heterogeneous material, or defectiveness occurring in the specimen without changes or destruction of internal structure using ultrasound, radiation, electromagnetism, fluid, heat, or light. In this study, among such non-destructive testing methods, the impact echo method was used for an experiment to estimate the steel rebar location and thickness in the concrete mock member. The mix was made with design standard strength of 30MPa, and for the steel rebar, diameter 22mm was used on the specimen of 300×370×200 to install spacer on the ground surface, and after separating by 40mm, it was arranged with 130mm and 150mm from the top of the specimen to the top of the rebar in 1 column and 3 rows. The specimen for thickness estimation was manufactured with total length of 1800×300 and 6 varying thicknesses of 150mm, 180mm, 210mm, 240mm, 270mm, and 300mm. As the result of rebar location estimation, the maximum resonant frequency was found to be 11269Hz, 9453Hz,and the rebar location estimates were 127.8mm and 151.8mm, which was relatively accurate with error rate of 1.72% and 1.19% from the actual value. In case of thickness estimation specimen, the error rates comparing actually measured thickness and the average value were 2.2%, 2.2%, 4.6%, 0.9%, 3.8%, and 4.7%, which were relatively accurate with average of 3.1%. Through this study, the applicability of steel rebar location and thickness estimation in concrete members using impact echo method could be confirmed.
Technology and Properties of (1-x)PZT-(x)PFW Ceramics with 0.25<x<0.55
Authors: Skulski Ryszard , Nogas-Cwikiel Ewa , Bochenek Dariusz , Niemiec Przemysław , Wawrzała Paweł
Published: April 2014

We present the results of obtaining and investigating ceramic samples of solid solution (1-x)(PbZr0.53Ti0.47O3)-x (PbFe2/3W1/3O3) [i.e. (1-x)PZT-xPFW] with x = 0.25, 0.35, 0.45 and 0.55 obtained from oxides using conventional ceramic technology. In this paper we present the results of investigations of XRD and main dielectric properties. For x = 0.25 and x = 0.35 we investigated also P-E hysteresis loops at room temperature.
Is Low Frequency Excess Noise of GMI Induced by Magnetization Fluctuations?
Authors: Dolabdjian Christophe , Dufay Basile , Saez Sebastien , Yelon Arthur , Ménard David
Published: April 2014

We have investigated the possible impact of low frequency magnetization fluctuations on the equivalent magnetic excess noise of GMI sensors, which we have recently shown to exhibit 1/f noise. This noise component is not associated with the detailed measuring setup nor with the conditioning electronic noise sources, suggesting that it is intrinsic to the sensing element. Various intrinsic GMI noise sources might be able to explain this observation; these include magnetic domain wall motion, hysteresis loop losses, etc. Since GMI elements are excited by a high frequency current, it has been assumed that these low frequency (lf) intrinsic noise sources cannot interact with the carrier and the sensed signal. We recall that the GMI effect is based on an impedance variation, which is governed by magnetization angle variations. These are modulated by the sensed signal and the lf magnetization noise, which then appear as sidebands around the carrier frequency. Applying the fluctuation-dissipation theorem to the GMI model, we have related both the signal and noise to the magnetic susceptibility spectrum and thus quantified the equivalent magnetic noise of GMI sensors at lf. We then present a preliminary comparison to our previous experimental results.
Analysis of Hysteretic Behavior in a PBZTS Ceramics by a Preisach Distribution
Authors: Wawrzała Paweł , Bochenek Dariusz
Published: April 2014

This paper presents a new way of using the classical Preisach distribution to the analytical description of the behavior of ceramic ferroelectrics in a wide range of temperatures. The iteration method have been used to investigate the Preisach distribution from polarization-electric field hysteresis loops to observe the composition and temperature variation of the some parameters in lead barium zirconate titanate stannate ceramic samples. Received Preisach distributions from P-E hysteresis loops were modeled by selected analytical functions to find useful parameters to observing the evolution of the hysteresis loops with temperature. This type of analysis can allow a more complete understanding of the relaxor properties occurring in these kind of materials, and may be used to examination the changes of temperature changes of piezoelectric sensors.
Influence of Filler Geometry on Melt Strength of Poly(lactid acid) Composites with Different Electrically Conductive Fillers
Authors: Frąckowiak Stanislaw , Kozlowski Marek
Published: April 2014

Polymer materials manufactured of natural resources have been characterized. Polylactid acid (PLA) was used as a matrix for composites filled with carbonaceous fillers of different geometry (carbon black and carbon nanofibres). Polymer strands made of electrically conductive PLA composites have a promising potential as materials for fabrication of sensors sensitive to strain, temperature or organic solvents. For better understanding of the correlation between processing parameters of PLA composites and their sensing ability the melt characteristics have been evaluated using a capillary rheometer and Rheotens melt strength tester. Strain sensing was monitored under three point bending by means of electrical conductivity measurements.
Total Ionizing Dose Effects on CMOS Image Sensors with Deep-Trench Isolation
Authors: Ahmed Nayera , Lu Guo Neng , Roy François
Published: April 2014

We have investigated Total Ionizing Dose (TID) effects on a 1.4μm-pitch, Deep-Trench Isolation (DTI) CMOS image sensor for its use in radiation environment. Our investigation includes characterization and TCAD simulations (with parametric modeling) of the image sensor before and after irradiation with 60Co gamma rays source for TID from 3 to 100 Krad. We have obtained agreements between measured results and simulated ones on degradations of the characteristics Quantum Efficiency (QE) and dark current (Idark). The agreements validate our modeling and simulation approach to evaluating these characteristics. It has been shown that TID causes evolution of interface states of different parts of the pixel, which are responsible for QE and Idark degradations. TID effects on different parts of the pixel can be identified and quantified.
The Effect of Sheet Resistivity and Storage Conditions on Sensitivity of RuO2 Based pH Sensors
Authors: Manjakkal Libu , Cvejin Katarina , Kulawik Jan , Zaraska Krzysztof , Szwagierczak Dorota
Published: April 2014

The increasing fresh water deficiency due to environmental pollution demands accurate, reliable and highly sensitive sensors for online monitoring of water pollution. Solid state sensors are helpful for fabricating and implementing low cost wireless sensors for monitoring of pollution. In water pollution determination, the measurement of pH plays an important role. Among the semiconductor sensitive materials RuO2 shows good sensitivity to hydrogen ions, high accuracy and resistance to interferences caused by other dissolved ions. In this work, thick film RuO2 based pH sensitive electrodes are fabricated by screen printing. The sensors were characterized by electromotive force measurements, SEM, optical microscopy and EDS analysis. The effects of sheet resistivity of the material and storage conditions are discussed. The sensor exhibits a sensitivity of 60 mV/pH in wide pH range of 2 to 10. The obtained response was very close to the theoretical Nernstian behavior. The best performance was attained for a sensor fabricated from 10 kΩ/sq. thick film paste and stored at water for 25 days.