Characterization of prototype secondary lithium battery

The performance characteristics of ambient temperature secondary lithium batteries were determined through continuous cycle tests with periodic current and voltage measurements. Cycle life of the lithium anode was found to be an important problem area as was the formation of dentrite breakage and subsequent shorting. Energy density was increased by using more efficient cathode structures

Charge Control Investigation of Rechargeable Lithium Cells

An ambient temperature rechargeable Li-TiS2 cell was cycled under conditions which simulate aerospace applications. A novel charge/discharge state-of-charge control scheme was used, together with tapered current charging, to overcome deleterious effects associated with end-of-charge and end-of-discharge voltages. The study indicates that Li-TiS2 cells hold promise for eventual synchronous satellite-type applications. Problem areas associated with performance degradation and reconditioning effects are identified

Transport of persistent organic pollutants across the human placenta

Environment International 65, 107-115 (2014

Onset of superconductivity in sodium and potassium intercalated molybdenum disulphide

Molybdenum disulfide in the form of natural crystals or powder has been intercalated at -65 to -70 C with sodium and potassium using the liquid ammonia technique. All intercalated samples were found to show a superconducting transition. A plot of the percent of diamagnetic throw versus temperature indicates the possible existence of two phases in the potassium intercalated molybdenum disulfide. The onset of superconductivity in potassium and sodium intercalated molybdenite powder was found to be approximately 6.2 and approximately 4.5 K, respectively. The observed superconductivity is believed to be due to an increase in electron density as a result of intercalation

Durable antistatic coating for polymethylmethacrylate

A durable antistatic coating is achieved on polymethylmethacrylate plastic without affecting its optical clarity by applying to the surface of the plastic a low molecular weight solvent having a high electron affinity and a high dipole moment, such as acentonitrile or nitromethane alone or in the presence of photopolymerizable monomer. The treated polymethylmethacrylate plastic dissipates most of the induced electrostatic charge and retains its optical clarity. The antistatic behavior persists after washing, rubbing and vacuum treatment

Low-resistivity homogeneous elastomers

Mixture of polyurethane polyelectrolyte and soluble, conducting organic compound produces homogeneous elastomer which has resistivity several orders of magnitude less than polyelectrolyte alone. Elastomeric material has novel resistivity dependence on temperature, that is, resistivity changes dramatically over narrow temperature range in vicinity of glass transition temperature

The risco of Cantillana’s Divina Pastora (Seville): survival, aesthetics and allegorical doctrinal content of a sacred scenery from baroque origin

El risco es una escenografía sacra efímera, destinada al culto, que se instala cada año en la localidad de Cantillana con motivo de sus festividades marianas. Data del siglo XVIII y posee un hondo significado doctrinal y alegórico de raíz tardobarroca, que se analiza en el presente estudio.The risco is a sacred and liturgic ephimeral scenery which is set up annually in Cantillana town (Seville) for the Marian religious festivities. It comes from 18th century and has a deep allegorical doctrinal content from Baroque origin

Performance and flow dynamics in cross-flow turbines

Aquesta tesi doctoral presenta l'estudi que l'autor va realitzar per comprendre l'efecte de l'angle pitch de la pala sobre les interaccions pala-estela que tenen lloc dins el rotor i, per tant, sobre el rendiment d'una turbina de flux creuat amb tres pales rectes. En primer lloc, hem estudiat experimentalment el rendiment d'aquest tipus de turbina en un túnel de vent de capa límit. Ho vam fer per a diferents pitches fixos de les pales, i amb diferents nombres de Reynolds basats en el diàmetre de la turbina que cobreixen la regió de transició en què el parell produït per les pales va superar el parell resistiu oposat. La forma i els valors de la corba de rendiment van canviar dràsticament amb només un increment de l'angle pitch fix. Com més gran sigui el nombre de Reynolds, menor és el tip speed ratio òptim i més cap al toe-out es mou l'angle pitch ideal. Posteriorment, vam estudiar experimentalment la dinàmica de flux dins el rotor per diferents pitches de la pala en un tanc d'aigua amb carro, usant Digital Particle Image Velocimetry. Els assajos es van realitzar a un nombre de Reynolds basat en el diàmetre de la turbina constant, i per a un rang de tip speed ratios. L'atenció se centra en l'anàlisi de les interaccions pala-estela dins el rotor. Angles toe-in i excessius toe-out s'han associat a baixos rendiments d'aquest tipus de turbines. La investigació ens ha permès relacionar les interaccions pala-estela amb les diferències de rendiment en aquest tipus de turbines, en funció del tip speed ratio i de l'angle pitch de la pala.Esta tesis doctoral presenta el estudio que el autor realizó para comprender el efecto del ángulo pitch de la pala sobre las interacciones pala-estela que tienen lugar dentro del rotor y, por lo tanto, sobre el rendimiento de una turbina de de flujo cruzado con tres palas rectas. En primer lugar, hemos estudiado experimentalmente el rendimiento de este tipo de turbina en un túnel de viento de capa límite. Lo hicimos para diferentes pitches fijos de las palas, y con diferentes números de Reynolds basados en el diámetro de la turbina que cubren la región de transición en la que el par producido por las palas superó al par resistivo opuesto. La forma y los valores de la curva de rendimiento cambiaron drásticamente con sólo un incremento del ángulo pitch fijo. Cuanto mayor sea el número de Reynolds, menor es el tip speed ratio óptimo y más hacia el toe-out se mueve el ángulo pitch ideal. Posteriormente, estudiamos experimentalmente la dinámica de flujo dentro del rotor para diferentes pitches de la pala en un tanque de agua con carro, usando Digital Particle Image Velocimetry. Los ensayos se realizaron a un número de Reynolds basado en el diámetro de la turbina constante, y para un rango de tip speed ratios. La atención se centra en el análisis de las interacciones pala-estela dentro del rotor. Ángulos toe-in y excesivos toe-out se han asociado a bajos rendimientos de este tipo de turbinas. La investigación nos ha permitido relacionar las interacciones pala-estela con las diferencias de rendimiento en este tipo de turbinas, en función del tip speed ratio operativo y del ángulo pitch de la pala.This doctoral thesis presents the study that the author have carried out in order to understand the effect of the blade pitch angle on the blade-wake interactions that take place inside the rotor, and hence on the performance of a three straight bladed cross-flow turbine. Firstly, we have experimentally studied the performance of this kind of turbine in a boundary layer wind tunnel. We did it for different fixed blade pitches, and at different turbine diameter Reynolds numbers covering the transitional region in which the torque produced by the blades overtook the opposed resistive torque. Shape and values of the performance curve changed drastically with just an increment of the fixed pitch angle. The higher the Reynolds number, the lower the optimal tip speed ratio and the more towards toe-out the ideal pitch angle is moved. Afterwards, we study experimentally the flow dynamics inside the rotor for different blade pitches in a water towing tank, using planar Digital Particle Image Velocimetry. Tests were made at a constant turbine diameter Reynolds number, and for a range of tip speed ratios. The focus is given to the analysis of the blade-wake interactions inside the rotor. Toe-in and excessive toe-out angles have been associated to low performances of this type of turbines. The investigation has allowed us to relate the blade-wake interactions with the performance differences in this type of turbines, as a function of both the operational tip speed ratio and the blade pitch angle