bluuebunny/crossref_metadata_2025 huggingface dataset:
Vegetation Greenness in Northeastern Brazil and Its Relation to ENSO Warm Events
Authors: Erasmi Stefan , Schucknecht Anne , Barbosa Marx , Matschullat Joerg
Published: April 2014

The spatio-temporal variability of trends in vegetation greenness in dryland areas is a well-documented phenomenon in remote sensing studies at global to regional scales. The underlying causes differ, however, and are often not well understood. Here, we analyzed the trends in vegetation greenness for a semi-arid area in northeastern Brazil (NEB) and examined the relationships between those dynamics and climate anomalies, namely the El Nino Southern Oscillation (ENSO) for the period 1982 to 2010, based on annual Normalized Difference Vegetation Index (NDVI) values from the latest version of the Global Inventory Modeling and Mapping Studies (GIMMS) NDVI dataset (NDVI3g) dataset. Against the ample assumption of ecological and socio-economic research, the results of our inter-annual trend analysis of NDVI and precipitation indicate large areas of significant greening in the observation period. The spatial extent and strength of greening is a function of the prevalent land-cover type or biome in the study area. The regression analysis of ENSO indicators and NDVI anomalies reveals a close relation of ENSO warm events and periods of reduced vegetation greenness, with a temporal lag of 12 months. The spatial patterns of this relation vary in space and time. Thus, not every ENSO warm event is reflected in negative NDVI anomalies. Xeric shrublands (Caatinga) are more sensitive to ENSO teleconnections than other biomes in the study area.
Integration and Diffusion in Sustainable Development Goals: Learning from the Past, Looking into the Future
Authors: Kanie Norichika , Abe Naoya , Iguchi Masahiko , Yang Jue , Kabiri Ngeta , Kitamura Yuto , Mangagi Shunsuke , Miyazawa Ikuho , Olsen Simon , Tasaki Tomohiro , Yamamoto Taro , Yoshida Tetsuro , Hayakawa Yuka
Published: April 2014

One of the next major challenges for research and policy on sustainability is setting the post-2015 Development Agenda. This challenge arises as a direct result of the formal ending of the Millennium Development Goals (MDGs) in 2015 and as an outcome of the 2012 United Nations Conference on Sustainable Development (Rio+20). The post-2015 Development Agenda is expected to include two agendas: one on human well-being to advance the MDG targets and the other on planetary well-being, which requires a safe “operating space” within the Earth’s life-support system. In contrast to the MDGs, the Sustainable Development Goals (SDGs) are meant to apply to both developing and developed countries and create a space for development within the stable functioning of the Earth’s systems. However, what might this all look like? For answers, this paper reviews the achievements and reflections of the MDGs to date and identifies new challenges entailed in the shift of development goals from “millennium” to “sustainable”. While most of the existing studies look at these two sets of issues separately, combining the two reveals two important features of the SDGs. First, SDGs need to integrate both human and planetary well-being in a goal, and second, goals, or sub-goals, need to be formulated at multiple levels, from global to local levels. While the MDGs represented no integrated goals, some of the existing proposals on SDGs include integrated goals. However, our analysis has shown that they do not present the vertical diffusion of goals. Considering both integration and diffusion in the architecture of SDGs is a remaining task.
« De nouveaux et étranges éducateurs » : dangers de la lecture et remèdes littéraires, 1883-1914
Authors: Proulx François
Published: April 2014

En las primeras décadas de la III ª República, inquietos discursos denunciaban «una intoxicación literaria» de la cual serían víctimas los jóvenes franceses bajo la influencia de sobreabundantes y desmoralizantes lecturas. Ensayistas y pedagogos coinciden en la necesidad de enseñar a los adolescentes, por medio de atractivas pero cuidadas lecturas, de enfrentar la literatura con discernimiento y moderación. Muchos escritores, como Paul Bourget y Maurice Barrès, proponen a título personal una novela de tipo didáctico, que propicie la identificación del lector con un personaje-lector, y así plantear una paradójica prevención contra los peligros de la lectura
Lecture et apprentissage de l’identité nationale. Étude de manuels scolaires belges (1842-1939)
Authors: Boudart Laurence
Published: April 2014

A partir del análisis de un amplio corpus de textos en lengua francesa, utilizados en la escuela primaria belga entre 1842 y 1939, y presentes en manuales de lectura, que consideramos como los vectores de una visión concreta del nacionalismo, procuramos poner de relieve de qué se compone la identidad colectiva que los responsables del sistema educativo han querido transmitir a los alumnos belgas. Concretamente, este artículo contempla dos de los ejes de afirmación de la identidad belga : la valentía como signo distintivo y la unidad del país. Plantea también la hipotésis según la cual la lectura, en la primera etapa de la escolarización, constituye una correa de trasmisión de primer orden entre las intenciones y las representaciones del poder establecido y el conjunto más amplio posible de futuros patriotas.

Título : Lectura y aprendizaje de la identidad nacional. Análisis de manuales escolares belgas (1842-1939).
La lecture dans le Guide bleu : du pouvoir au désir
Authors: Vergopoulos Hécate
Published: April 2014

El análisis de la Guía Azul de España publicado por Roland Barthes en las Mitologías, en 1957, es un proyecto que consiste en actualizar la dimensión política del texto. El presente artículo propone prolongar dicho proyecto sobre las guías contemporáneas con el fin de ver, más allá de las transformaciones que las obras de esta colección hayan tenido, cómo podemos pensar en la actualidad la dimensión política de las guías de viaje. Haciendo eco de los trabajos de Michel de Certeau, Barthes muestra que las guías han construido una representación de la lectura que descansa sobre un modelo táctico de la práctica, tomando el cuidado de olvidar que éste debería definirse como una respuesta a un modelo estratégico. De este modo las guías pretenderían haber construido una figura apolítica de la práctica de lectura a través de la cual se ejercen, por lo tanto, las relaciones latentes con el poder que se esconden detrás de los rastros del deseo.
POWER UNITS AND POWER SUPPLY SYSTEMS IN UAV
Authors: Cwojdziński Leszek , Adamski Mirosław
Published: April 2014

One of the major tasks in the process of designing future unmanned aerial vehicles is the appropriate choice of a propulsion system and a power source. Depending on the role and size of a given UAV, the following engines are used: electric, jet, turbine and piston (combustion). The following paper also analyses the faultiness of UAVs. Moreover, the most appropriate propulsion systems and power sources depending on the type and description of the mission performed by a UAV are recommended.
Les élections générales de 2013 au Kenya
Authors: Thibon Christian
Published: March 2014

Les élections kényanes de mars 2013 apparaissent exceptionnelles, du moins atypiques : pacifiques alors que la bipolarisation politique, comme les précédentes confrontations électorales violentes, laissait craindre le pire. Mais l’optimisme dégagé est mitigé par une mobilisation ethnique qui reproduit le clivage fondateur de l’histoire kényane alors que la victoire d’Uhuru Kenyatta, de justesse au premier tour, pas si surprenante au regard d’une campagne électorale fort médiatisée, ouvre un nouveau cycle politique, toujours marqué par les pesanteurs et les défis du passé. Cet événement, et les inconnues qu’il soulève, dévoilerait-il une nouvelle donne dans la vie politique kényane, dans la géopolitique et dans la société qui connaît de forts bouleversements économiques et socioculturels ?
La CPI, Dieu et les élections kényanes de 2013
Authors: Maupeu Hervé
Published: March 2014

L’inculpation de deux leaders politiques, Uhuru Kenyatta et William Ruto, a constitué l’un des enjeux principaux de la campagne électorale de 2013. Ces deux inculpés ont constitué une alliance politique improbable rassemblant les deux principales ethnies qui s’étaient opposées lors des violences post-électorales de 2008. Ils ont habilement recristallisé l’identité politique de leur communauté respective en diffusant des discours de victimisation et en formulant une relecture de l’histoire de leur ethnie faisant d’eux des héros. Cette stratégie a bien fonctionné car ils ont usé efficacement d’un registre religieux, de type néo-pentecôtiste, donnant une grande force à leur message de repentance et d’autojustification. Ils se sont fabriqué une nouvelle virginité et l’impunité des élites kényanes s’en est trouvé ainsi renouvelée. Ce faisant, ils ont également infléchi la culture politique du pays en développant une véritable « pentecôtisation » de la vie politique. Depuis le scrutin de 2013, l’État kényan s’est donné pour priorité absolue d’assurer l’impunité de ses dirigeants.
Commission électorale et Cour suprême kényane à l'épreuve du scrutin
Authors: Wolfrom Marie
Published: March 2014

Après les terribles violences qui ont suivi les élections de décembre 2007, le Kenya s’est doté en 2010 d’une nouvelle constitution. Celle-ci prévoyait notamment la création d’une commission électorale (Independant Electoral and Boundaries Commission, IEBC) et d’une Cour suprême chargée d’arbitrer tout litige lié à une élection présidentielle. Le scrutin du 4 mars 2013 constituait donc une première mise à l’épreuve pour ces deux institutions. Mais, si celles-ci ont contribué à assurer des élections plus paisibles, elles ne sont pas parvenues à éviter tous les écueils. Les coûteux systèmes électroniques mis en place par la commission électorale pour tenter de garantir la transparence et l’équité du scrutin ont failli et le dépouillement des résultats a été lent et sujet au doute. Quant à la Cour suprême, qui a finalement validé le scrutin, elle a vu son jugement critiqué comme manquant de profondeur et d’une solide argumentation juridique. Ces deux institutions, qui devaient symboliser une renaissance démocratique après le désastre de 2007-2008, sont sorties fragilisées des élections de mars 2013.
« Mayotte département », la fin d'un combat ?
Authors: Idriss Mamaye
Published: March 2014

La départementalisation de Mayotte, en mars 2011, est venue satisfaire une des plus vieilles revendications portées par le Mouvement populaire mahorais (MPM). Une rétrospective sur le combat de ce parti méconnu et sur les origines de cette revendication s’impose. La posture francophile adoptée par le MPM, dès sa formation, témoigne en effet de pratiques politiques originales. L’étude de ses différents discours et de ses pratiques permet de mieux comprendre l’enjeu que constituait l’accession au statut de département français et sur quels fondements reposait cette revendication.
Comportamiento, para el terremoto de Lorca de 11-05-2011, de edificios de vigas planas proyectados sin tener en cuenta la acción sísmica
Authors: Domínguez D. , López-Almansa F. , Benavent-Climent A.
Published: April 2014

El terremoto de Lorca (11-05-2011) fue el movimiento sísmico más destructivo registrado en España, a pesar de su moderada magnitud. Este artículo describe la simulación numérica de la respuesta dinámica, al registro principal del terremoto de Lorca, de seis edificios de tres y seis plantas con forjados unidireccionales de hormigón con vigas planas; estos edificios fueron proyectados sin tener en cuenta la acción sísmica. Se ha elegido esta tipología constructiva por presentar, potencialmente, una elevada vulnerabilidad sísmica. Los seis edificios han sido seleccionados para representar un número importante de edificios de este tipo existentes en zonas de sismicidad baja o media (como Lorca) de España y correspondientes a los años 1974-1994, posteriores a la PDS-1 1974 y previos a la NCSE-94. Los resultados obtenidos muestran que estos edificios, aun contando con la cooperación de los muros, no poseen capacidad para resistir la componente más intensa del registro de Lorca.
Metadata in Serbia
Authors: Sofronijevic Adam , Dakic Natasa , Andonovski Jelena
Published: April 2014

This chapter discusses the usage of metadata in libraries in Serbia. So far metadata have been used for describing printed documents available for patrons in library holdings and for describing digital documents available in online repositories. Paper presents some specific aspects of metadata usage primarily in regards to automation of digital data delivery for patrons. The advent of information technologies provides librarians in Serbia, as well as their colleagues in other countries, with powerful tools to describe digital objects and interconnect them making those related digital objects effectively available for users via an emergent, more semantic web.
An Integrated Notation for Business Process Models
Authors: Bruno Giorgio
Published: April 2014

Since business processes may address complex behavioral requirements resulting from the integration of several items, i.e. tasks, business entities (also called artifacts), control flow rules and data flow rules, they need notations able to accommodate several viewpoints. This chapter proposes a notation, ARTS, aimed at integrating the traditional activity-oriented viewpoint and the artifact-oriented one. The major benefits are the unification of the control flow and the data flow and a clear representation of the choices to be carried out by the participants. The basic features are illustrated with the help of three versions of a simplified hiring process. This chapter also deals with the structure of work lists, which are the major interface between the participants and their tasks. The organization of the work lists leverages the artifacts to emphasize human choices; for this reason, the traditional linear structure is replaced with a network one, which shows the artifacts along with their states, correlations and valid options.
Cultural Product Management from Environment to Territorial Context
Authors: Ferri Maria Antonella , Dominici Gandolfo , Basile Gianpaolo , Aiello Lucia
Published: April 2014

This chapter aims to represent the evolution of the cultural vocation of the territory with relation to the cultural product. The authors achieve this by adopting a holistic, viable-systemic approach. This approach proves useful to draw a better representation of the relationships existing among members of the territory - which is a prerequisite for the creation of any cultural product - and among them and the stakeholders to whom the cultural product itself is targeted. The authors consider the notion of relationship as a form of interactive connection determining - in causal fashion - a series of input-output effects among system members.
Cultural Sponsorship and Entrepreneurial Mistrust
Authors: Severino Fabio
Published: April 2014

Company sponsorships are a way to fund cultural management, allowing cultural organizers to be independent, especially in those countries where this sector is supported mainly by public funds. This chapter discusses the results of a survey the author conducted in Rome, Italy. Theoretically, in this city with a great cultural heritage, there are many opportunities of sponsorships both for companies looking for good tools of communication (i.e. for tourism targets) and for cultural managers asking for money to carry out better work and to make long term plans. Using a questionnaire of 20 closed questions, in a face-to-face way, the author asked 345 firms how, when and where they have been working with sponsorship tools. The main result of the survey indicates that there is often a problem of communication between these two different worlds: the cultural sector and commercial firms.
Submicron Electrode Gaps Fabricated by Gold Electrodeposition at Interdigitated Electrodes
Authors: van Megen M.J.J. , Olthuis W. , van den Berg A.
Published: April 2014

Electrodes with submicron gaps are desired for achieving high amplication redoxcycling sensors. In this contribution we report the use of electrodeposition of gold in order todecrease the inter-electrode spacing at interdigitated electrodes. Using this method submicronspacings can be obtained without expensive techniques such as e-beam lithography or focusedion beam milling. Initially, gold interdigitated electrodes with a nger spacing of 2.5 m wererealized by lift-o processing. Using a commercial gold sulphite bath (ECF64D) and 100 mscurrent pulses of -1.78 A, these gold electrodes were plated with an additional gold layer. Asa result, the inter- electrode spacing, as measured using atomic force microscopy and conven-tional microscopy, was reduced to 0.6 m. The achieved gap spacing is limited by electrodeimperfections resulting from the lift-o process. At these imperfections the electrodes becomeshorted. Additional experiments with wet etched electrodes are expected to yield smaller gapspacings
Voltammetric Behavior of Peptide-Modified Porous Silicon after Metal Complexation
Authors: Sam Sabrina , Gouget-Laemmel Anne Chantal , Chazalviel Jean Noël , Ozanam François , Etcheberry Arnaud , Belhousse S. , Gabouze N.
Published: April 2014

Hybrid nanomaterials based on organic layer covalently grafted on porous silicon (PSi) nanostructure appear as promising systems for innovative applications such as detecting of traces amounts and/or removing metal cations in water effluents. In this work, we focused on the functionalization of the PSi nanostructure by the peptide GlyCysGlyCys, which forms stable complexes with metal ions. This property is exploited to achieve toxic metal recognition in water using electrochemical methods. Peptide immobilization was achieved using multi-step reactions; GlyCysGlyCys was anchored on a previously prepared carboxyl-terminated PSi surface, using EDC/NHS coupling agents. This scheme is compatible with the mild conditions required for preserving the probe activity of the peptide. At each step of the functionalization, the surface was monitored by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Electrochemical behavior of such modified electrode was carried out after Nickel accumulation on the surface, by means of cyclic voltammetry. The recorded cyclic voltammograms showed a quasi-irreversible process corresponding to the Ni2+/Ni0 couple.
Electrical Resistance and Seebeck Effect in Undoped Polycrystalline Zinc Oxide
Authors: Hossein-Babaei Faramarz , Masoumi S.
Published: April 2014

Thermoelectric properties of metal oxide semiconductors are of increasing interest in the field of sensors design and fabrication. The oxide components in the majority of such applications are polycrystalline in which the charge transportation is controlled both by the microstructure and the bulk properties of the material. While the dependence of the electrical resistivity on the microstructural and compositional changes in these materials is well understood, the complications encountered with their thermoelectric properties, have remained unattended. Here, we report experimental data on the Seebeck coefficient of undoped polycrystalline zinc oxide measured on the ceramic pellets fabricated by dry pressing of the powder and sintering at 800 and 1000°C, in air. Aluminum ohmic contacts are used for electrical connections. Seebeck voltage and electrical resistivity are measured at various temperatures and different atmospheric condition at the presence of predetermined temperature gradients.
Fluorescent Probes for the Selective Detection of Cysteine in Water
Authors: Kim Hae Jo
Published: April 2014

Two novel fluorescent chemodosimeters will be presented for the selective detection of cysteine over homocysteine and glutathione in aqueous solvent. First, a rhodamine-based fluorescent probe (1) will be reported. Masked with a para-hydroxybenzyl alcohol (HBA) unit, probe 1 initially showed a weak fluorescence but displayed a strong fluorescence through a series of reactions of Michael addition and intramolecular cyclization of cysteine, followed by deprotection of HBA. The caged probe (1) exhibited a selective and sensitive response toward cysteine over homocysteine and glutathione in HEPES buffer. Secondly, a fluorescein-based fluorescent probe will be discussed. A bromoacetyl functionalized fluorescein chemodosimeter (2) was utilized as a fluorescent probe for cysteine. The probe showed a selective and sensitive response to cysteine over homocysteine and glutathione in aqueous buffer through a rapid cyclization reaction. When cysteine was added, a fast fluorescence turn-on change of 2 was observed and applied to the in-vivo imaging of cysteine.
Bond of High Strength Concrete with Recycled Coarse Aggregate and Reinforcing Bar
Authors: Kim Seung Hun , Lee Yong Taeg , Hong Seong Uk
Published: April 2014

This study conducted a comparative evaluation of bond behavior according to the steel reinforcing type and substitution rate of recycled coarse aggregate. Mixed as high-strength concrete of design strength 50MPa in order to verify the applicability of recycled coarse aggregate concrete as a structural member. Total of 24 specimens were manufactured with variables of recycled aggregate substitution rate (0%, 30%, 50%, 100%), steel reinforcing arrangement direction (vertical, horizontal top·bottom) and steel reinforcing types (SD400 D16, D19). The specimen was produced according to CSA S802-02 and ASTM 234. specimens using D16 reinforcing, the vertical reinforcing showed similar bond stress regardless of the recycled aggregate substitution rate and slip amount, and for the horizontal reinforcing, the bottom specimen showed similar bond stress as the vertical reinforcing and slip amount. The top specimen showed slightly less bonds tress than vertical and horizontal bottom specimens. This is thought to have been caused by the subsidence of the aggregate. The specimen using D19 reinforcing showed similar bond stress in vertical · horizontal top · bottom, horizontal top reinforcing maximum bond stress, horizontal bottom reinforcing maximum bond stress and showed no difference due to aggregate subsidence like in D16. As the result, Bond stress in this study is larger than 2.0fck, the value proposed by CEB-FIP code. The specimen using D16 reinforcing bar showed 4.5fck and the specimen using D19 reinforcing bar was near 3.9fck. Therefore, since the standard value is satisfied regardless of replacement rate of recycled aggregate, natural aggregate in high strength concrete can be substituted by recycled aggregate.
Development of Novel Polymer Oxide Thick Film for Sensor Sensing Layers at Room Temperature
Authors: Gaidan Ibrahim
Published: April 2014

This work deals with the new technique employed in the fabrication of thick film which includes material selection, functional materials, milling / drying / pressing, firing and cooling, binder / solvent, substrate preparation, pastes preparation, the screen printing process and drying the sensing layers. A novel approach to electronic nose-head design, using a copper thin film electrode patterning technique was used to deposit electrodes on the alumina substrate. The responses of the sensors to propanol was investigated. The response / recovery times of all the sensors were improved compared to those deposited on glass substrates. For example, the response time for all the NiO / Fe2O3 devices at 4000 ppm was less than 10 sec., while the recovery time were 30 sec for both the 75 / 25 and the 50 / 50 mol. % NiO / Fe2O3 sensors and 20 sec for the 75 / 25 % NiO / Fe2O3 sensor. The response / recovery times of those sensors fabricated on glass substrates were 30 / 45, 45 / 55 and 60 / 85 at the same solvent vapour and concentration.
The Kinetically Dominated Overgrowth of Flower-Like Silver Nanostructures and its Application for Surface-Enhanced Raman Scattering
Authors: Zhou Ning , Li Dong Sheng , Yang De Ren
Published: April 2014

Herein flower-like silver nanostructures with different size and ratio of hexagonal close-packed (HCP) to face-centered cubic (FCC) phase were synthetized. By comparing with the results utilizing different surfactants, the growth process of Ag nanostructures has been investigated. Flower-like Ag nanoparticles containing numerous hot spots could serve as excellent surface-enhanced Raman scattering (SERS) substrates, and the Raman signal of Rhodamine 6G with the concentration as low as 10-6 M can be recognized.
Development of Hybrid Piezoelectric Materials for Tactile Sensing
Authors: di Donato Marco , Bocchini Sergio , Canavese Giancarlo , Cauda Valentina , Lombardi Mariangela
Published: April 2014

As the robotics is moving its interest from the machine tools for industrial production to biomimetic, even human-like systems, the need for materials that fulfill skin role arises. Skin presents a structure that has multiple roles such as protection and tact. The basic requirements for a skin mimetic material are flexibility and a measurable physical property triggered by the pressure. In this work hybrid piezoelectric materials are prepared and characterized. The flexibility of materials is assured by the polymeric matrices while ceramic oxide fillers grant a piezoelectric response. Polyvinilidene fluoride (PVDF) is used both in its piezoactive β-form and piezopassive α-form, in order to investigate the contribution of the organic phase to the overall response. Polymethylmethacrylate (PMMA) is also used in order to compare the behavior of an amorphous and a semi-crystalline polymer. Lead-based ceramics were avoided, despite they are known to be the most effective piezoelectric materials, to prevent complications in terms of toxicity. Ceramic materials with lower piezoelectric coefficient, but more suitable for human robotics such as barium titanate and zinc oxide are preferred. Organic matrices and ceramic powders are then employed for preparing composites with different compositions, microstructures and mechanical behaviors, in order to evaluate their piezoelectric response in view of their application as sensing skin for robots.
Energy Efficiency and System Control of Street Lighting Using Wireless Sensors Network and Actuators
Authors: Lucia Felipe Lorenzo Della , Manera Leandro Tiago , Frazatto Felipe Cassaro
Published: April 2014

This paper presents the development and implementation of a wireless system for street lighting control and monitoring, focusing on its energy efficiency and reliability. Each node of the network consists of a lamp connected to an electronic dimmable ballast through a control unit and a radio module. The network is designed using the 802.15.4 IEEE protocol and it is implemented using a mesh topology at 2.45 GHz. It is possible to adjust the power consumption and luminosity of each lamp at a particular point (or street) relative to traffic intensity or safety considerations, saving a considerable amount of energy. It is also possible to adjust the luminosity of the lamp according to the environment light by using a radiant sensor present in the control unit and check the lamp status (on or off). The entire network is monitored by self-proprietary software, and also includes the ability to make decisions depending on local sensors. Each node can also be used as a router to transmit the information from one node to another in order to extend the distance range the network can achieve. The main advantages of this system are the reduction of costs related to energy consumption and the ability to detect in a short time a lamp failure. Results show that it is possible to reduce the power consumption of a single lamp by 69%. The network range was adequate and each node itself could transmit and receive commands 130 m apart.
Simulation of Grain Size Effects on Gas Sensing Characteristics of Semiconductor Sensors in Nitrogen Oxides Detection
Authors: Liu Jian Qiao , Quan Lin
Published: April 2014

The grain size effects on gas sensing characteristics of semiconductor gas sensor are simulated based on the model of gradient distributed oxygen vacancies, which describes the dynamics of oxygen vacancies in an idealized cooling process. Sensor resistance and response to oxidizing gases, as functions of grain size (RC) and depletion layer width (w), are calculated from the steady-state vacancy distribution in the depletion layer through Poissons equation. Simulation curves are plotted to fit the experimental data from WO3 and In2O3 sensors in nitrogen oxides detection. The fitting results illustrate the applicability of the model on quantitative interpretation of the grain size effects on oxidizing gas detection. The widths of depletion layer in WO3 and In2O3 nanograins are estimated.
Surface Acoustic Wave Sensors Based on Nanoporous Films for Hydrogen Detection
Authors: Viespe Cristian
Published: April 2014

Surface Acoustic Wave Sensor is one of the most promising detection systems due tosmaller size, lower weight, power requirements and great sensitivity. It is known from the liter-ature that Pd and ZnO are the most promising materials for detecting hydrogen. A nanoporousPd and ZnO based layered SAW sensors have been developed and investigated for hydrogen,at room temperature. The sensors were of a delay line type (quartz substrate, 70 MHz cen-tral frequency). The nanoporous sensitive layer was directly deposited onto a quartz substrateusing a picosecond laser ablation method. Lasers with picosecond pulses or a high repetitionrate leads to major changes in the ablation process and implicit in the deposited lm struc-ture. Thus, using such a regime, at a certain ambient gas pressure, we have the advantage ofdirectly obtaining a nanoporous lm. The sensor performances (sensitivity, limit of detectionand response time), for a hydrogen concentration in synthetic air of 0.015 2 % were studied.For a concentration between 0.2 - 0.8 % hydrogen/synthetic airs, the response times was 15 -44 s and 6 - 27 s in case of Pd lms and ZnO respectively. Limit of detection was about 6.3times better at Pd sensors (50 ppm) than ZnO sensors (315 ppm).
Investigations on the Equivalent Magnetic Noise of Magneto(Elasto)Electric Sensors by Using Modulation Techniques
Authors: Zhuang Xin , Lam Chok Sing Marc , Dolabdjian Christophe , Finkel Peter , Li Jie Fang , Viehland Dwight
Published: April 2014

The equivalent magnetic noise of the magnetoelectric (ME) layered composite sensors has been investigated for various modulation techniques. The ME thin film response to an electric modulation or a magnetic modulation can be sensed by using either a charge amplifier or a coil wound around the sample and then demodulated by a synchronous detector. The equivalent magnetic noise for these excitations methods has been compared. As expected, the low-frequency fluctuations can be lowered when the magnetoelectric sensor is operated in a modulation mode. Results show that these methods can give the same level of equivalent magnetic noise for a certain strain-excitation. In theory, mechanical noise appears as the only dominant noise source after the demodulation process in the case of a certain strong amplitude excitation carrier signal. By using these modulation techniques, an equivalent magnetic noise level of 10-100 pT/Hz at 1 Hz was achieved with DC capability.
Preparation and Crystallization Kinetics of FeSiB Amorphous Ribbons under Non-Isothermal Regime
Authors: Varouti Eirini
Published: April 2014

The aim of the present work was the preparation and characterization of FeSiB amorphous magnetic ribbons with the following chemical composition: Fe80SixB20-x, x=5,6,8 and Fe75Si15B10. Differential Scanning Calorimetry was employed in order to study the thermal stability and structural changes during the transformations that took place. Much emphasis is placed on the analysis of the crystallization kinetics.
TiO2 Nano-Powders as Potential Low-Temperature Optical Gas Sensors
Authors: Eltermann Marko , Lange Sven , Utt Kathriin , Joost Urmas , Kink Ilmar , Kiisk Valter , Sildos Ilmo
Published: April 2014

Present work investigates the applicability of nanosized TiO2 (anatase) as a potential optical sensor material for ambient oxygen below room temperature. Titania nanopowders with grain sizes of 10 and 40 nm are prepared via the sol-gel route and tested for the gas response in water deficit conditions. Both powders exhibit sensitivity against oxygen. At-50 °C 40 nm grain size powder remains sensitive to the ambient changes and the PL output increases ~50% whereas 10 nm grain size powders photoluminescence is quenched.
Application of a Ag Ductile Layer in Minimizing Si Die Stresses in LDMOS Packages
Authors: Fragoudakis Roselita , Zimmerman Michael A. , Saigal Anil
Published: April 2014

Lateral Diffused Metal Oxide Semiconductors (LDMOS) normally have a Cu-W flange, whose CTE is matched to Si. Low cost Cu substrate material provides 2X high thermal conductivity, and along with a AuSi eutectic solder is recommended for optimal thermal performance. However, the CTE mismatch between Cu and Si can lead to failure of the semiconductor as a result of die fracture, due to thermal stresses developed during the soldering step of the manufacturing process. Introducing a Ag ductile layer is very important in minimizing such thermal stresses and preventing catastrophic failure of the semiconductor. Ag is a ductile material electroplated on the Cu substrate to absorb stresses developed during manufacturing due to the CTE mismatch between Si and Cu. The Ag layer thickness affects the magnitude of the resulting thermal stresses. This study attempts to measure the yield strength of the Ag layer, and examines the optimal layer thickness to minimize die stresses and prevent failure. The yield stress of the ductile layer deposited on a Cu flange was measured by nanoindentation. The Oliver and Pharr method was applied to obtain modulus of elasticity and yield depth of Ag. A finite element analysis of the package was performed in order to map die stress distribution for various ductile layer thicknesses. The analysis showed that increasing the ductile layer thickness up to 0.01 - 0.02 mm, decreases the Si die stresses.
Visible Light Sensor Based on Metal-Oxide-Semiconductor Structure
Authors: Nedev Nicola , Arias Abraham , Curiel Mario , Nedev Roumen , Mateos David , Manolov Emil , Nesheva Diana , Valdez Benjamin , Herrera Rigoberto , Sanchez Alejandro
Published: April 2014

We present results for the effect of visible and UV light on the capacitance-voltage characteristics of a p-type Si based Metal-Oxide-Semiconductor ring-dot structure. It is shown that the structure can be used as a low cost sensor that is simple and easy to manufacture. The sensor can be used to measure visible and UV light intensity or as a light switch. The output signal is change of the inversion capacitance under light illumination at a given bias. The device power consumption is very low and the output signal is independent of the temperature.
Piezoelectric Self-Excited System in Mining Roof Anchor Stress Change Measurement
Authors: Kwaśniewski Janusz , Dominik Ireneusz , Lalik Krzysztof
Published: April 2014

The paper presents the application of a new type of a measurement system called Self-excited Acoustical System (SAS). It was applied for stress change monitoring of anchors which are used to secure roofs and walls in mines and in hollowed tunnels. The knowledge about the state of anchors can indirectly indicate the state of rock masses which is crucial for mining safety. One of the main problems so far has been reliable sensor mounting, especially in difficult mining conditions. The SAS system overcomes this problem because it can be mounted easily at the anchors end or even on the anchors flange.
The laboratory tests were conducted on a hydraulic tensile testing machine. The mining roof anchor was placed in the machine and then stretched. The changes of the resonance frequency caused by the increase of the tensile strength were observed during the research.
Modal Analysis of Gallium Nitride Membrane for Pressure Sensing Device
Authors: Dzuba Jaroslav , Držík Milan , Vanko Gabriel , Rýger Ivan , Vallo Martin , Kutiš Vladimír , Lalinský Tibor
Published: April 2014

A circular high electron mobility transistor (C-HEMT) prepared on the AlGaN/GaN membrane surface has been investigated and its potential for pressure sensing has been already demonstrated. The key issue in the design process of such heterostructure based MEMS sensors is the stress engineering. This way we can scale the sensor performance, measured pressure range and sensitivity. Especially, the knowledge of the exact value of the residual stress in membranes (caused by deposition process) helps us to optimize the sensing devices. In this work, the residual stress determination method in gallium nitride circular shaped membrane is reported. It is shown that resonant frequency method using Laser Doppler Vibrometry (LDV) for membrane vibration measurement seems to be an appropriate technique to determine the residual stress in micro-scale membranes. Circularly shaped AlGaN/GaN micro-membranes are excited by acoustic short time pulse. The decay oscillating motion of the membrane is recorded by oscilloscope. By FFT spectral analysis of the signals the resonance frequencies are obtained. For the sample studied, the natural frequency mode resonance peak is used to define the residual stress level. To verify the observed stress in investigated membranes, prestressed modal analysis in finite element method (FEM) code ANSYS is performed. The stress extracted from the measured frequency is taken as an initial stress state of the modelled membrane. Experimentally obtained shock spectra are compared with that computed by FEM simulation.
Optical Properties of Composite Films Based on Copper Chloride in PMMA Matrix
Authors: Gerbreders Andrejs , Bulanov Andrejs , Sledevskis Eriks , Gerbreders Vjaceslavs , Teteris Janis
Published: April 2014

The composite lms based on PMMA, CuCl2 and photoinitiator were prepared.Transmission spectra of the lms with and without photoinitiator were measured. The holo-graphic gratings were recorded, the sensitivity of the lms and surface structure of gratingswere studied. Microanalysis of the lms was performed in di erent part of structure elementsof grating.
Influence of Dipolar Interactions in Ferroelectric Vinylidene Fluoride Copolymers on their Structure and Low-Temperature Molecular Mobility
Authors: Kochervinskii Valentin V. , Malyshkina I.A. , Pavlov A.S. , Bessonova N.P. , Kozlova N.V. , Shmakova N.A.
Published: April 2014

Dielectric, IR spectroscopy and DSC measurements were made over a wide range of temperatures and frequencies in copolymers of vinylidene fluoride (VDF) with tetra- (TFE) and trifluoroethylene (TrFE) of different composition. Experimental results show that decrease of VDF content in VDF/TFE copolymers is accompanied by decrease of activation energy of kinetic units in the glassy state, though relaxation times of cooperative mobility in amorphous phase differ insignificantly. Substitution of TFE with TrFE in copolymers with the same VDF content increases activation energy values for the local mobility. The results of IR spectroscopy suggest that VDF/TFE copolymers with low VDF content have lower crystallinity, which may be explained by the secondary crystallization processes and absence of long isomers in planar zigzag conformation.
Drift-Like Terms Minimization in the Responses of a Generic Tin Oxide Gas Sensor
Authors: Amini Amir , Shabani Pejman , Gharesi Mohsen
Published: April 2014

The responses of a tin oxide gas sensor vary with humidity level in the surrounding atmosphere. Such response variations can cause error in the estimation of the concentration level of the target gas and need compensation measures. Different methods have been used to compensate the effect of humidity, which usually require utilization of other parallel environmental sensors and costly data fusion methodology. Particularly, such a drift alters the response patterns obtained from a real or virtual sensor array and hinders gas recognition. Here, we report response patterns recorded from a virtual array made by operating temperature modulation at different ambient humidity levels for three different target gases. Humidity level varied from 30-70% and response patterns were recorded for methanol, ethanol and 1-propanol at a wide concentration range. It is shown that by utilizing the thermal shock-induction method for the temperature modulation of the sensor, the drift levels are low, and with a single set of training data collected at RH=50%, responses obtained in the whole humidity range can be discriminated from each other. The clusters volumes in the feature space grow with the span of the ambient humidity variations, but they remain separate allowing gas recognition.
Electrochemical Measurements of Phenothiazine Drugs in the Presence of Surface Active Ionic Liquids
Authors: Talwar Reshu , Mahajan Rakesh Kumar
Published: April 2014

The present study aims to explore the interactions between phenothiazine drugs (viz. promethazine hydrochloride (PMT) and promazine hydrochloride (PMZ)) and 1-alkyl-3-butylimidazolium based surface active ionic liquids (SAILs) using conductivity, cyclic voltammetry and DPV measurements. The drugs have been found to form mixed micelles with the SAILs and thus vary the micellar parameters of SAILs as evaluated from conductivity measurements,. Moreover, phenothiazine drugs are known to exhibit redox behavior which is prone to change in the presence of SAILs. This change in the redox active behavior is seen to be dependent on the concentration as well as the nature of the alkyl chain of both drugs and SAILs. The interactions between the drugs and the SAILs have been found to be electrostatic as well as hydrophobic.
Fabrication of Diamond Based Quartz Crystal Microbalance Gas Sensor
Authors: Varga Marián , Laposa Alexandr , Kulha Pavel , Davydova Marina , Kroutil Jiri , Husak Miroslav , Kromka Alexander
Published: April 2014

Synthetic diamond has remarkable properties comparable with natural diamond and hence is a very promising material for many various applications (sensors, heat sink, optical mirrors, cold cathode, tissue engineering, etc.). Nowadays, deposition of diamond films is normally employed in chemical vapor deposition (CVD) usually at high temperatures (800900 °C), what limit its application to high melting substrates. Gravimetric (mass) sensors belong to the major categories of chemical sensors and the most common type of mass sensor is the bulk acoustic quartz crystal microbalance (QCM). This contribution deals with a nanocrystalline diamond (NCD) growth from the H2/CH4/CO2 gas mixture at low temperature (400 °C) by pulsed linear antenna microwave plasma system on 10 MHz circular AT-cut quartz resonators substrate. Gas sensor based on the NCD-coated QCM was developed for detection of ammonia (NH3) at room temperature. Measurements not only confirmed the functionality of this first published NCD-coated QCM sensor, but in addition its sensitivity was twofold to a virgin QCM sensor with a gold active layer.
Tuning the Molecular Sensitivity of Conductive Polymer Resistive Sensors by Chemical Functionalization
Authors: Frontera Evelina , Cavallo Pablo C. , Olejnik Robert , Acevedo Diego F. , Slobodian Petr , Barbero Cesar A. , Saha Petr
Published: April 2014

Polyaniline thin films are chemically functionalized by nucleophilic addition of thiols beareing different functional groups: carboxylic, amine, -dodecyl and sulfonic. The modification is tested using FTIR and XPS spectroscopy. Then, the films are used as resistive sensors for different volatile organic compounds in a static measuring system. The sensitivity of conducting polymers to alcohols and heptane is strongly affected by the chemical functionalization of the materials. Polyaniline show an increasing signal when the chain length of different alcohols is increased. The incorporation of hydrophilic groups on the PANI chains seems to maintain the trend. On the other hand, the polymer modified with a long alkyl chain (PANI-DOT) show negative response for methanol and the signal increases up to propanol to decrease for longer chains. PANI-DOT show the largest signal for heptane of all polymers tested. Therefore, the functional group attached to the conductive polymer chain can be used to tune the molecular sensitivity of the resistive sensor
Non-Destructive Methods for Measuring Steel Properties: A Portable, Low-Cost Electromagnetic Sensor Based on the MBN Phenomenon
Authors: Asimakopoulos Konstantinos D.
Published: April 2014

The design and development of a low cost, portable magnetic Barkhausen Noise Sensor is presented. The health of ferromagnetic objects can be monitored by analyzing MBN response. Comparative estimations of the location and size of any microstructural defects or previously applied tensions can be obtained. Each stage of the sensor is presented along with explanatory circuit diagrams, and descriptions of the magnetization and the receiving coil are given. The device can perform accurate, non-destructive measurements of steel magnetic properties, and has an advantage over currently available commercial sensors in terms of both cost and size.
Dielectric Behaviour of BaTiO3-SrTiO3 Solid Solutions Fabricated by High-Energy Ball Milling
Authors: Dulian Piotr , Bąk Wojciech , Wieczoek-Ciurowa Krystyna , Kajtoch Czesław
Published: April 2014

This paper considers the mechanochemical synthesis of advanced electroceramic material with a perovskite structure as well as this method as an effective way for modifying the properties of BaTiO3 by substitution of foreign ions. Dielectric properties mainly para-ferroelectric phase transitions in Ba1-xSrxTiO3 solid solutions (0.0 x 0.6) are presented.
Coagulation Sensors Based on Magnetostrictive Sensors Made by Ferromagnetic Amorphous Alloys for Biomedical Applications
Authors: Koutelieris G.
Published: April 2014

Coagulation sensors are magnetostrictive sensors for measuring the time required for coagulation to take place in a liquid, as blood. Their operating principle is based on magnetostrictive delay lines (MDL), which consist of ribbons made by ferromagnetic amorphous alloys. Coagulation sensors have a significant role in biomedical, chemical engineering and environmental applications.
Electrodeposited Ni100-XFex Thin Films on Copper Substrates
Authors: Messaadi Saci , Daamouche Mosbah , Medouer Hadria
Published: April 2014

Due to their soft operational capacity and magnetic properties, Iron Nickel alloys are of great commercial interest. A simple and inexpensive technique for the production of Nickel-Iron thin films is electrodeposition. A lot of physical and chemical parameters (substrates, concentration, current density, potential, temperature, pH, agents of addition......) can significantly influence the physical properties, such as homogeneity, bright, structure and morphology of the Ni-Fe deposits. This paper presents a study into some characteristics of Ni-Fe deposits on Copper substrates.
All the electrochemical experiments were performed in a three electrode cell in which the volume of the bath was 150ml. Electrodeposition of Ni-Fe was carried out potensiostatically from a Brenner type electrolytic bath in [0.1 aqueous solutions of Ni-Fe. The applied potential is-1.20V and the deposition time varies from 10 min to 30 min for all experiments.