Spray pyrolysed In2S3 thin films: A potential electron selective layer for large area inverted bulk-heterojunction polymer solar cells

In this paper, we report the results of investigations on the potential of spray pyrolysis technique in depositing electron selective layer over larger area for the fabrication of inverted bulk-heterojunction polymer solar cells. The electron selective layer (In2S3) was deposited using spray pyrolysis technique and the linear heterojunction device thus fabricated exhibited good uniformity in photovoltaic properties throughout the area of the device. An MEH-PPV:PCBM inverted bulk-heterojunction device with In2S3 electron selective layer (active area of 3.25 3.25 cm2) was also fabricated and tested under indoor and outdoor conditions. Fromthe indoor measurements employing a tungsten halogen lamp (50mW/cm2 illumination), an opencircuit voltage of 0.41V and a short-circuit current of 5.6mA were obtained. On the other hand, the outdoor measurements under direct sunlight (74mW/cm2) yielded an open-circuit voltage of 0.46V and a short-circuit current of 9.37mA

Synthesis and Photoluminescence Properties of Novel Red Phosphors for White Light Emitting Diode Applications

Several series of Eu3+ based red emitting phosphor materials were synthesized using solid state reaction route and their properties were characterized. The present studies primarily investigated the photoluminescence properties of Eu3+ in a family of closely related host structure with a general formula Ln3MO7. The results presented in the previous chapters throws light to a basic understanding of the structure, phase formation and the photoluminescence properties of these compounds and their co-relations. The variation in the Eu3+ luminescence properties with different M cations was studied in Gd3-xMO7 (M = Nb, Sb, Ta) system.More ordering in the host lattice and more uniform distribution of Eu3+ ions resulting in the increased emission properties were observed in tantalate system.Influence of various lanthanide ion (Lu, Y, Gd, La) substitutions on the Eu3+ photoluminescence properties in Ln3MO7 host structures was also studied. The difference in emission profiles with different Ln ions demonstrated the influence of long range ordering, coordination of cations and ligand polarizability in the emission probabilities, intensity and quantum efficiency of these phosphor materials. Better luminescence of almost equally competing intensities from all the 4f transitions of Eu3+ was noticed for La3TaO7 system. Photoluminescence properties were further improved in La3TaO7 : Eu3+ phosphors by the incorporation of Ba2+ ions in La3+ site. New red phosphor materials Gd2-xGaTaO7 : xEu3+ exhibiting intense red emissions under UV excitation were prepared. Optimum doping level of Eu3+ in these different host lattices were experimentally determined. Some of the prepared samples exhibited higher emission intensities than the standard Y2O3 : Eu3+ red phosphors. In the present studies, Eu3+ acts as a structural probe determining the coordination and symmetry of the atoms in the host lattice. Results from the photoluminescence studies combined with the powder XRD and Raman spectroscopy investigations helped in the determination of the correct crystal structures and phase formation of the prepared compounds. Thus the controversy regarding the space groups of these compounds could be solved to a great extent. The variation in the space groups with different cation substitutions were discussed. There was only limited understanding regarding the various influential parameters of the photoluminescence properties of phosphor materials. From the given studies, the dependence of photoluminescence properties on the crystal structure and ordering of the host lattice, site symmetries, polarizability of the ions, distortions around the activator ion, uniformity in the activator distribution, concentration of the activator ion etc. were explained. Although the presented work does not directly evidence any application, the materials developed in the studies can be used for lighting applications together with other components for LED lighting. All the prepared samples were well excitable under near UV radiation. La3TaO7 : 0.15Eu3+ phosphor with high efficiency and intense orange red emissions can be used as a potential red component for the realization of white light with better color rendering properties. Gd2GaTaO7 : Eu3+, Bi2+ red phosphors give good color purity matching to NTSC standards of red. Some of these compounds exhibited higher emission intensities than the standard Y2O3 : Eu3+ red phosphors. However thermal stability and electrical output using these compounds should be studied further before applications. Based on the studies in the closely related Ln3MO7 structures, some ideas on selecting better host lattice for improved luminescence properties could be drawn. Analyzing the CTB position and the number of emission splits, a general understanding on the doping sites can be obtained. These results could be helpful for phosphor designs in other host systems also, for enhanced emission intensity and efficiency.

Quality oriented drying of Lemon Balm (Melissa officinalis L.)

Heilkräuter sind während des Trocknungsprozesses zahlreichen Einflüssen ausgesetzt, welche die Qualität des Endproduktes entscheidend beeinflussen. Diese Forschungsarbeit beschäftigt sich mit der Trocknung von Zitronenmelisse (Melissa officinalis .L) zu einem qualitativ hochwertigen Endprodukt. Es werden Strategien zur Trocknung vorgeschlagen, die experimentelle und mathematische Aspekte mit einbeziehen, um bei einer adäquaten Produktivität die erforderlichen Qualitätsmerkmale im Hinblick auf Farbeänderung und Gehalt an ätherischen Ölen zu erzielen. Getrocknete Zitronenmelisse kann zurzeit, auf Grund verschiedener Probleme beim Trocknungsvorgang, den hohen Qualitätsanforderungen des Marktes nicht immer genügen. Es gibt keine standardisierten Informationen zu den einzelnen und komplexen Trocknungsparametern. In der Praxis beruht die Trocknung auf Erfahrungswerten, bzw. werden Vorgehensweisen bei der Trocknung anderer Pflanzen kopiert, und oftmals ist die Trocknung nicht reproduzierbar, oder beruht auf subjektiven Annäherungen. Als Folge dieser nicht angepassten Wahl der Trocknungsparameter entstehen oftmals Probleme wie eine Übertrocknung, was zu erhöhten Bruchverlusten der Blattmasse führt, oder eine zu geringe Trocknung, was wiederum einen zu hohen Endfeuchtegehalt im Produkt zur Folge hat. Dies wiederum mündet zwangsläufig in einer nicht vertretbaren Farbänderung und einen übermäßigen Verlust an ätherischen Ölen. Auf Grund der unterschiedlichen thermischen und mechanischen Eigenschaften von Blättern und Stängel, ist eine ungleichmäßige Trocknung die Regel. Es wird außerdem eine unnötig lange Trocknungsdauer beobachtet, die zu einem erhöhten Energieverbrauch führt. Das Trocknen in solaren Tunneln Trocknern bringt folgendes Problem mit sich: wegen des ungeregelten Strahlungseinfalles ist es schwierig die Trocknungstemperatur zu regulieren. Ebenso beeinflusst die Strahlung die Farbe des Produktes auf Grund von photochemischen Reaktionen. Zusätzlich erzeugen die hohen Schwankungen der Strahlung, der Temperatur und der Luftfeuchtigkeit instabile Bedingungen für eine gleichmäßige und kontrollierbare Trocknung. In Anbetracht der erwähnten Probleme werden folgende Forschungsschwerpunkte in dieser Arbeit gesetzt: neue Strategien zur Verbesserung der Qualität werden entwickelt, mit dem Ziel die Trocknungszeit und den Energieverbrauch zu verringern. Um eine Methodik vorzuschlagen, die auf optimalen Trocknungsparameter beruht, wurden Temperatur und Luftfeuchtigkeit als Variable in Abhängigkeit der Trocknungszeit, des ätherischer Ölgehaltes, der Farbänderung und der erforderliche Energie betrachtet. Außerdem wurden die genannten Parametern und deren Auswirkungen auf die Qualitätsmerkmale in solaren Tunnel Trocknern analysiert. Um diese Ziele zu erreichen, wurden unterschiedliche Ansätze verfolgt. Die Sorption-Isothermen und die Trocknungskinetik von Zitronenmelisse und deren entsprechende Anpassung an verschiedene mathematische Modelle wurden erarbeitet. Ebenso wurde eine alternative gestaffelte Trocknung in gestufte Schritte vorgenommen, um die Qualität des Endproduktes zu erhöhen und gleichzeitig den Gesamtenergieverbrauch zu senken. Zusätzlich wurde ein statistischer Versuchsplan nach der CCD-Methode (Central Composite Design) und der RSM-Methode (Response Surface Methodology) vorgeschlagen, um die gewünschten Qualitätsmerkmalen und den notwendigen Energieeinsatz in Abhängigkeit von Lufttemperatur und Luftfeuchtigkeit zu erzielen. Anhand der gewonnenen Daten wurden Regressionsmodelle erzeugt, und das Verhalten des Trocknungsverfahrens wurde beschrieben. Schließlich wurde eine statistische DOE-Versuchsplanung (design of experiments) angewandt, um den Einfluss der Parameter auf die zu erzielende Produktqualität in einem solaren Tunnel Trockner zu bewerten. Die Wirkungen der Beschattung, der Lage im Tunnel, des Befüllungsgrades und der Luftgeschwindigkeit auf Trocknungszeit, Farbänderung und dem Gehalt an ätherischem Öl, wurde analysiert. Ebenso wurden entsprechende Regressionsmodelle bei der Anwendung in solaren Tunneltrocknern erarbeitet. Die wesentlichen Ergebnisse werden in Bezug auf optimale Trocknungsparameter in Bezug auf Qualität und Energieverbrauch analysiert.

Effect of within-litter birth weight variation on piglet survival and pre-weaning weight gain in a commercial herd

There are several factors that affect piglet survival and this has a bearing on sow productivity. Ten variables that influence pre-weaning vitality were analysed using records from the Pig Industry Board, Zimbabwe. These included individual piglet birth weight, piglet origin (nursed in original litter or fostered), sex, relative birth weight expressed as standard deviation units, sow parity, total number of piglets born, year and month of farrowing, within-litter variability and the presence of stillborn or mummified littermates. The main factors that influenced piglet mortality were fostering, parity and within-litter variability especially the weight of the individual piglet relative to the average of the litter (P<0.05). Presence of a mummified or stillborn littermate, which could be a proxy for unfavourable uterine environment or trauma during the birth process, did not influence pre-weaning mortality. Variability within a litter and the deviation of the weight of an individual piglet from the litter mean, influenced survival to weaning. It is, therefore, advisable for breeders to include uniformity within the litter as a selection criterion. The recording of various variables by farmers seems to be a useful management practice to identify piglets at risk so as to establish palliative measures. Further, farmers should know which litters and which piglets within a litter are at risk and require more attention.

A Multi-scale Model for Copper Dishing in Chemical-Mechanical Polishing

The present success in the manufacture of multi-layer interconnects in ultra-large-scale integration is largely due to the acceptable planarization capabilities of the chemical-mechanical polishing (CMP) process. In the past decade, copper has emerged as the preferred interconnect material. The greatest challenge in Cu CMP at present is the control of wafer surface non-uniformity at various scales. As the size of a wafer has increased to 300 mm, the wafer-level non-uniformity has assumed critical importance. Moreover, the pattern geometry in each die has become quite complex due to a wide range of feature sizes and multi-level structures. Therefore, it is important to develop a non-uniformity model that integrates wafer-, die- and feature-level variations into a unified, multi-scale dielectric erosion and Cu dishing model. In this paper, a systematic way of characterizing and modeling dishing in the single-step Cu CMP process is presented. The possible causes of dishing at each scale are identified in terms of several geometric and process parameters. The feature-scale pressure calculation based on the step-height at each polishing stage is introduced. The dishing model is based on pad elastic deformation and the evolving pattern geometry, and is integrated with the wafer- and die-level variations. Experimental and analytical means of determining the model parameters are outlined and the model is validated by polishing experiments on patterned wafers. Finally, practical approaches for minimizing Cu dishing are suggested.

A Two-level Prediction Model for Deep Reactive Ion Etch (DRIE)

We contribute a quantitative and systematic model to capture etch non-uniformity in deep reactive ion etch of microelectromechanical systems (MEMS) devices. Deep reactive ion etch is commonly used in MEMS fabrication where high-aspect ratio features are to be produced in silicon. It is typical for many supposedly identical devices, perhaps of diameter 10 mm, to be etched simultaneously into one silicon wafer of diameter 150 mm. Etch non-uniformity depends on uneven distributions of ion and neutral species at the wafer level, and on local consumption of those species at the device, or die, level. An ion–neutral synergism model is constructed from data obtained from etching several layouts of differing pattern opening densities. Such a model is used to predict wafer-level variation with an r.m.s. error below 3%. This model is combined with a die-level model, which we have reported previously, on a MEMS layout. The two-level model is shown to enable prediction of both within-die and wafer-scale etch rate variation for arbitrary wafer loadings.

A Multi-scale Model for Copper Dishing in Chemical-Mechanical Polishing

The present success in the manufacture of multi-layer interconnects in ultra-large-scale integration is largely due to the acceptable planarization capabilities of the chemical-mechanical polishing (CMP) process. In the past decade, copper has emerged as the preferred interconnect material. The greatest challenge in Cu CMP at present is the control of wafer surface non-uniformity at various scales. As the size of a wafer has increased to 300 mm, the wafer-level non-uniformity has assumed critical importance. Moreover, the pattern geometry in each die has become quite complex due to a wide range of feature sizes and multi-level structures. Therefore, it is important to develop a non-uniformity model that integrates wafer-, die- and feature-level variations into a unified, multi-scale dielectric erosion and Cu dishing model. In this paper, a systematic way of characterizing and modeling dishing in the single-step Cu CMP process is presented. The possible causes of dishing at each scale are identified in terms of several geometric and process parameters. The feature-scale pressure calculation based on the step-height at each polishing stage is introduced. The dishing model is based on pad elastic deformation and the evolving pattern geometry, and is integrated with the wafer- and die-level variations. Experimental and analytical means of determining the model parameters are outlined and the model is validated by polishing experiments on patterned wafers. Finally, practical approaches for minimizing Cu dishing are suggested.

Diagnóstico de apendicitis aguda en la edad pedíatrica en la Fundación Cardio Infantil : utilidad de la ultrasonografía

Los niños que presentan dolor abdominal agudo representan una de las principales demandas de atención en los servicios de Urgencias Pediátricas, convirtiéndose en un reto para quien realiza la valoración inicial la decisión de que paciente amerita realizar estudios adicionales, para descartar una patología quirúrgica. Considerando que la apendicitis es la primera emergencia quirúrgica en niños, y que sus complicaciones son un problema frecuente, es imprescindible que el clínico conozca cual es la utilidad y beneficio que le brindan las herramientas diagnósticas disponibles para realizar un diagnóstico más certero. Objetivo: Describir el manejo de los pacientes menores de 18 años con sospecha de apendicitis en la FCI y determinar la sensibilidad y especificidad de la ecografía en esta población. Métodos: Estudio de Prueba Diagnóstica. Revisión expedita de los niños valorados en la FCI con sospecha clínica de apendicitis aguda durante un periodo de 4 meses. Se tomaron datos de hallazgos ecográficos para apendicitis (positivos, negativos o indeterminados) y del desenlace de tener o no apendicitis. Posteriormente se realizó una inferencia mediante una tabla de contingencia, teniendo en cuenta intervalos de confianza para determinar la sensibilidad, especificidad, VPP, VPN y exactitud de la prueba basados en el diagnóstico final. Resultados: En 52% de pacientes que consultaron por dolor abdominal se sospecho patología quirúrgica, grupo en el que se utilizó la ecografía abdominal como herramienta diagnóstica para descartar apendicitis encontrando: sensibilidad: 63%(IC 95%, 48.6-75.5), especificidad: 82,7%(IC 95%, 76- 87.8) y exactitud: 78,2%(IC 95%, 72-83,4). La prevalencia de la enfermedad fue 22,8%, con probabilidad postprueba positiva de 88.3%(IC 95%, 82,1-92.6). Conclusiones: Los resultados de este estudio evidencian un menor rendimiento de la ecografía como prueba diagnóstica para apendicitis en pediatría en nuestro medio comparado al descrito en la literatura. Dicha discordancia probablemente se encuentra determinada por los sesgos propios de un estudio histórico como este, en el que básicamente la falta de uniformidad en el registro de datos en la historia clínica por los observadores (clínicos y radiólogos), así como las limitaciones para determinar el seguimiento de todos los pacientes que no fueron operados, pueden alterar la capacidad operativa real de la prueba. De ahí la importancia de realizar a futuro un estudio concurrente.

Aproximación a un marco teórico para la construcción de una metodología para el estudio sistémico de sectores estratégicos

En la búsqueda de adaptabilidad por parte de las organizaciones, para sobrevivir y crecer frente a los cambios, así como de los procesos de formulación y revisión de la estrategia empresarial para la toma de decisiones, la exploración e interpretación del entorno, sus elementos y dinámica se han convertido en una necesidad apremiante. En este contexto, una de las herramientas que permite a las organizaciones mejorar la visión sectorial es la metodología del Análisis Estructural de Sectores Estratégicos (en adelante AESE). Esta visión que se construye a partir de la aplicación de dicha metodología se deriva de los procesos de análisis y de síntesis. En el mismo sentido, la falta de uniformidad del mundo actual, la cantidad de factores que impactan el desempeño organizacional y la complejidad de las interacciones que se dan en los sectores estratégicos conducen a la búsqueda un nuevo enfoque para comprenderlos e intervenirlos. Lo anterior debido a que es claro que desde el pensamiento analítico no se contemplan las múltiples interrelaciones en los sectores estratégicos, su permanente variación, ni los procesos circulares que en ellos se dan, por lo cual la visión que proporciona se considera limitada para comprender la realidad y guiar a los directivos empresariales en la toma de decisiones estratégicas. Por el contrario, el uso del pensamiento sistémico en el estudio sectorial sí posibilita la comprensión de los sectores como sistemas, su diseño, estructura (relaciones) y funcionamiento (dinámica) a fin de obtener una visión de conjunto para intervenirlos. Dentro de los beneficios que brinda la aplicación del pensamiento sistémico (dinámica de sistemas) se encuentra la posibilidad de simular un modelo dinámico que permite determinar el futuro de los sectores estratégicos y guiar a las organizaciones a la definición de políticas alineadas con la búsqueda de la perdurabilidad. Luego, el presente trabajo de investigación pretende establecer los elementos teóricos, conceptuales y metodológicos, asociados con la toma de decisiones estratégicas y con el pensamiento sistémico (dinámica de sistemas), que contribuyen a la construcción de una metodología para el Estudio Sistémico de Sectores Estratégicos (en adelante ESSE).

Irrigation performance and gross water productivity in furrow-irrigated ornamental tree production

In the ornamental plant production region of Girona (Spain), which is one of the largest of its kind in southern Europe, most of the surface is irrigated using wide blocked-end furrows. The objectives of this paper were: (1) to evaluate the irrigation scheduling methods used by ornamental plant producers; (2) to analyse different scenarios in order to assess how they affect irrigation performance; (3) to evaluate the risk of deep percolation; and (4) to calculate gross water productivity. A two-year study in a representative commercial field, planted with Prunus cerasifera ‘Nigra’, was carried out. The irrigation dose applied by the farmers was slightly smaller than the required water dose estimated by the use of two different methods: the first based on soil water content, and the second based on evapotranspiration. Distribution uniformity and application efficiency were high, with mean values above 87%. Soil water content measurements revealed that even at the end of the furrow, where the infiltrated water depth was greatest, more than 90% of the infiltrated water was retained in the shallowest 40 cm of the soil; accordingly, the risk of water loss due to deep percolation was minimal. Gross water productivity for ornamental tree production was € 11.70 m–3, approximately 20 times higher than that obtained with maize in the same region

The Syntactic Information in the 'Diccionario Crítico Etimológico Castellano e Hispánico' by J. Corominas and J.A. Pascual as Expressed in the Database 'Syntax.Dbf'

L'objectiu d'aquest article és presentar l'estructura de la base de dades relacional que inclou tota la informació sintictica continguda en el Diccionario Critico Etimológico Castellano e Hispánico de J. Corominas i J. A. Pascual. Tot i que aquest diccionari conté un ampli ventall d'informacions històriques de cadascun dels temes, aquestes no es mostren de forma estructurada, per la qual cosa ha estat necessari estudiar i classificar tots aquells elements relacionats amb aspectes sintàctics. És a partir d'aquest estudi previ que s'han elaborat els diferents camps de la base de dades, els quals s'agrupen en cinc blocs temàtics: informació lemàtica; gramatical; sintàctica; altres aspectes relacionats; i observacions o comentaris rellevants fets per l'investigador. Aquesta base de dades no només reprodueix els continguts del diccionari, sinó que inclou diferents camps interpretatius. Per aquesta raó, Syntax. dbf representa una eina de treball fonamental per a tots aquells investigadors interessats en la sintaxi diacrònica de l'espanyol

A Reabilitação face à Sustentabilidade : Casa Burguesa do Porto

Os centros históricos são o resultado de um parque habitacional corrente, com uma grande uniformidade, coerência construtiva e espaços urbanos de modo a proporcionar uma identidade própria. Um dos grandes problemas urbanos são as vastas áreas degradadas do ponto de vista arquitetónico como também social, cultural e económico. Conhecidos os principais problemas dos edifícios de habitação e suas causas, para sua resolução existe necessidade de adaptar o processo de reabilitação tradicional ao conceito de sustentabilidade. Estes dois assuntos conjugados são atualmente emergentes, devido à necessidade de reabilitação do parque habitacional, nomeadamente centros históricos. A casa burguesa do Porto apresenta um elevado grau de degradação, porém apesar de existentes as ações de intervenção que sobre ela reincidem, não são proporcionais à necessidade atual. A cidade do Porto é marcada, maioritariamente, pelas Casas Burguesas, das quais foram executadas segundo padrões de conforto e de utilização da época. É, então, fundamental um estudo pormenorizado da casa burguesa do Porto, avaliando o contexto em que esta se encere (na cidade e na respetiva habitação), os subsistemas construtivos e as praticas de reabilitação.

Los principios de interpretación de la Convención de las Naciones Unidas sobre los contratos de compraventa internacional de mercaderías (Tema Central)

Si bien los redactores de la Convención de las Naciones Unidas sobre los Contratos de Compraventa Internacional de Mercaderías no establecieron de manera expresa los métodos para adelantar la operación hermenéutica de este instrumento, sí previeron algunos principios que, en líneas generales, configuran un “sistema autónomo de interpretación” –acorde con las exigencias de su naturaleza internacional–, que se traduce en una operación de lógica jurídica que tiene por objeto determinar el alcance y sentido de los términos utilizados por la Convención y de los contratos que suscriban las partes. Este trabajo procura examinar el carácter internacional de la Convención, la necesidad de promover la uniformidad en su aplicación, y la de asegurar la observancia de la buena fe en el comercio internacional. En la segunda parte se analizan los criterios previstos en la Convención para la interpretación específica de las declaraciones y los actos realizados por las partes.

Migration and diversity in Roman Britain: a multidisciplinary approach to immigrants in Roman York, England

Previous anthropological investigations at Trentholme Drive, in Roman York identified an unusual amount of cranial variation amongst the inhabitants, with some individuals suggested as having originated from the Middle East or North Africa. The current study investigates the validity of this assessment using modern anthropological methods to assess cranial variation in two groups: The Railway and Trentholme Drive. Strontium and oxygen isotope evidence derived from the dentition of 43 of these individuals was combined with the craniometric data to provide information on possible levels of migration and the range of homelands that may be represented. The results of the craniometric analysis indicated that the majority of the York population had European origins, but that 11% of the Trentholme Drive and 12% of The Railway study samples were likely of African decent. Oxygen analysis identified four incomers, three from areas warmer than the UK and one from a cooler or more continental climate. Although based on a relatively small sample of the overall population at York, this multidisciplinary approach made it possible to identify incomers, both men and women, from across the Empire. Evidence for possible second generation migrants was also suggested. The results confirm the presence of a heterogeneous population resident in York and highlight the diversity, rather than the uniformity, of the population in Roman Britain. Am J Phys Anthropol 140:546-561, 2009. (C) 2009 Wiley-Liss, Inc

Short-range urban dispersion experiments using fixed and moving sources

Four perfluorocarbon tracer dispersion experiments were carried out in central London, United Kingdom in 2004. These experiments were supplementary to the dispersion of air pollution and penetration into the local environment (DAPPLE) campaign and consisted of ground level releases, roof level releases and mobile releases; the latter are believed to be the first such experiments to be undertaken. A detailed description of the experiments including release, sampling, analysis and wind observations is given. The characteristics of dispersion from the fixed and mobile sources are discussed and contrasted, in particular, the decay in concentration levels away from the source location and the additional variability that results from the non-uniformity of vehicle speed. Copyright © 2009 Royal Meteorological Society