Microwave dielectric properties of MO -La2O3-TiO2 (M = Ca, Sr, Ba) ceramics

Single-phase polycrystalline ceramics in the MO-La2O3-Ti02 (M = Ca, Sr, Ba) system, such as cation-deficient hexagonal perovskites CaLa4Ti4O15, SrLa4Ti4O15, BaLa4Ti4O15, and Ca2La4Ti5O18 and the orthorhombic phases CaLa4Ti5O17 and CaLa8Ti9O31, were prepared through the solid-state ceramic route. The phases and structure of the ceramics were analyzed through x-ray diffraction and scanning electron microscopy. The microwave dielectric properties of the ceramics were studied using a network analyzer. The investigated ceramics show high Er in the range 42 to 54, high quality factors with Q x f in the range 16,222 to 50,215 GHz, and low Tf in the range -25 to +6 ppm3/°C. These high dielectric constant materials with high Q x f up to 50,215 GHz are suitable for applications where narrow bandwidth and extremely low insertion loss is necessary, especially at frequencies around 1.9 GHz

Continuous Production of Extracellular L-Glutaminase by Ca-Alginate-Immobilized Marine Beauveria bassiana BTMF S-10 in Packed-Bed Reactor

L-Glutamine amidohydrolase (L-glutaminase, EC 3.5.1.2) is a therapeutically and industrially important enzyme. Because it is a potent antileukemic agent and a flavor-enhancing agent used in the food industry, many researchers have focused their attention on L-glutaminase. In this article, we report the continuous production of extracellular L-glutaminase by the marine fungus Beauveria bassiana BTMF S-10 in a packed-bed reactor. Parameters influencing bead production and performance under batch mode were optimized in the order-support (Na-alginate) concentration, concentration of CaCl2 for bead preparation, curing time of beads, spore inoculum concentration, activation time, initial pH of enzyme production medium, temperature of incubation, and retention time. Parameters optimized under batch mode for L-glutaminase production were incorporated into the continuous production studies. Beads with 12 × 108 spores/g of beads were activated in a solution of 1% glutamine in seawater for 15 h, and the activated beads were packed into a packed-bed reactor. Enzyme production medium (pH 9.0) was pumped through the bed, and the effluent was collected from the top of the column. The effect of flow rate of the medium, substrate concentration, aeration, and bed height on continuous production of L-glutaminase was studied. Production was monitored for 5 h in each case, and the volumetric productivity was calculated. Under the optimized conditions for continuous production, the reactor gave a volumetric productivity of 4.048 U/(mL·h), which indicates that continuous production of the enzyme by Ca-alginate-immobilizedspores is well suited for B. bassiana and results in a higher yield of enzyme within a shorter time. The results indicate the scope of utilizing immobilized B. bassiana for continuous commercial production of L-glutaminase

Raman and FTIR studies of the structural aspects of Nasicon-type crystals; AFeTi(PO4)3 [A ¼ Ca, Cd]

Raman and FTIR spectra of CaFeTi(PO4)3 and CdFeTi(PO4)3 are recorded and analyzed. The observed bands are assigned in terms of vibrations of TiO6 octahedra and PO4 tetrahedra. The symmetry of TiO6 octrahedra and PO4 tetrahedra is lowered from their free ion symmetry. The presence of Fe3+ ion disrupts the Ti–O–P–O–Ti chain and leads to the distortion of TiO6 octrahedra and PO4 tetrahedra. The PO4 3 tetrahedra in both crystals are linearly distorted. The covalency bonding factor of PO4 3 polyanion of both the crystals are calculated from the Raman spectra and compared to that of other Nasicon-type systems. The numerical values of covalency bonding factor indicates that there is a reduction in redox energy and cell voltage and is attributed to strong covalency of PO4 3 polyanionin

FT-IR and FT-Raman study of Nasicon type phosphates, ASnFe(PO4)3 [A=Na2, Ca, Cd]

FT-Raman and FT-IR spectra of ASnFe(PO4)3 [A=Na2, Ca, Cd] were recorded and analyzed. The bands were assigned in terms of the vibrational group frequencies of SnO6 octahedral and PO4 tetrahedral. The spectral analysis shows that the symmetry of corner shared octahedral (SnO6) and the tetrahedral (PO4) are lowered from their free ion symmetry state. The presence of Fe3+ ions disrupts the S–N–O–S–N chain in the structure. This causes distortion of SnO6 and PO4 in the structure of all the compounds. Also it is seen that there are two distinct PO4 tetrahedra of different P–O bond lengths. One of these tetrahedra is linearly distorted in all the title compounds. The PO4 frequencies and bond lengths are calculated theoretically and are in agreement with the experimental values. The presence of PO4 polyanion in the structure can reduce the redox energy and hence reduce the metal oxygen covalency strength in the structure

La Universidad profesional : relaciones entre la Universidad y la nueva Formaci??n Profesional

En febrero de 2003 se realiza un seminario especializado en Murcia sobre las relaciones entre la universidad y la nueva formaci??n profesional en el que se presentan las bases de un modelo de ense??anza superior de car??cter profesional, con implicaci??n directa de los sectores productivos y tutelado por las universidades. Se analizan experiencias concretas como las llevadas a cabo en Escuelas Universitarias Polit??cnicas de Matar??, Ja??n, la industrial de Igualada o las de iniciativa privada como la Gestio Skola del Pa??s Vasco.

Documentos del XIII Simposio sobre ense??anza de la geolog??a : Alicante del 5 al 10 de julio de 2004

Incluye el libro de salidas de campo: Geolog??a de Alicante

Concurrent Aggregates (CA): An Object-Oriented Language for Fine-Grained Message-Passing Machines

Fine-grained parallel machines have the potential for very high speed computation. To program massively-concurrent MIMD machines, programmers need tools for managing complexity. These tools should not restrict program concurrency. Concurrent Aggregates (CA) provides multiple-access data abstraction tools, Aggregates, which can be used to implement abstractions with virtually unlimited potential for concurrency. Such tools allow programmers to modularize programs without reducing concurrency. I describe the design, motivation, implementation and evaluation of Concurrent Aggregates. CA has been used to construct a number of application programs. Multi-access data abstractions are found to be useful in constructing highly concurrent programs.

Noves eines d'aprenentatge autònom en organització d'empreses

En un nou escenari on la formació canvia l’enfocament des del formador cap a l’alumne i on l’aprenentatge s’orienta de manera més autònoma i reflexiva, les noves tecnologies de la informació i comunicació (TIC) ofereixen un ampli ventall de possibilitats per desenvolupar millores en els processos formatius. Un grup de professors del Departament d’Economia i Organització d’Empreses de la Universitat de Barcelona estan treballant en el disseny i la implantació de nous recursos i materials docents innovadors, emmarcats en l’ús de les TIC, tant com a suport de la docència presencial com per recolzar-hi l’aprenentatge autònom. En aquest sentit, l’objectiu de la present comunicació és presentar l’experiència del professorat que la subscriu en l’ús de mitjans digitals i multimèdia per a l’aprenentatge de diverses assignatures de l’àrea d’Organització d’Empreses

III Jornadas de intercambio de experiencias educativas

Se recogen las experiencias presentadas en las terceras jornadas de intercambio de experiencias educativas celebradas en el CPR de Avil??s (Asturias) en septiembre de 2004, agrupadas en tres bloques: Materiales Multimedia, Educaci??n Vial y Atenci??n a la Diversidad. En estas jornadas los profesores/as de los centros educativos asturianos tienen la posibilidad de presentar sus propios materiales did??cticos adaptados a las m??ltiples situaciones del aula.

Experiencias en Educaci??n Vial

Resumen tomado de la publicaci??n

Nuevas tendencias en la evaluaci??n de la Educaci??n F??sica : jornadas regionales : 19, 20, 21, 22 y 23 de mayo 2009 : lugar, CPR Avil??s

Esta publicaci??n recoge los contenidos de las Jornadas Regionales sobre Nuevas Tendencias en la Evaluaci??n de la Educaci??n F??sica celebradas en el Centro del Profesorado y de Recursos de Avil??s y cuya finalidad ha sido la de propiciar un lugar de encuentro donde el profesorado de educaci??n primaria y secundaria intercambiase distintas experiencias y conocimientos. Se analiza y reflexiona sobre las pr??cticas de evaluaci??n, las estrategias que se est??n llevando a cabo con el alumnado, y cu??les son las ??ltimas corrientes aplicables en esta materia. Todo ello, con el objetivo de abrir nuevas v??as que enriquezcan y mejoren la pr??ctica docente y evaluadora.