Electroluminescence from phenylenevinylene-based polymer blends

The electroluminescent behaviour of films of poly(phenylphenylenevinylene) (PPPV), of PPPV blended with polystyrene (PS) and of PS doped with oligo(phenylenevinylene) sandwiched between indium–tin oxide (ITO) and Al contacts has been investigated. Polymer blending increases the relative quantum efficiency by up to two orders of magnitude. Studying the cell performance under application of rectangular voltage pulses as a function of temperature indicates that (i) hole injection at the ITO contact occurs by tunnelling, (ii) tunnel injection of electrons at the cathode is promoted by a space charge field across an interfacial Al₂O₃ layers and (iii) leakage of holes through the cathodic barrier is the main loss mechanism for holes.     

Adequacy assessment of composite power systems with HVDC linksusing Monte Carlo simulation

Direct current (DC) links are finding increasing use throughout the world in the form of long distance transmission and asynchronous interconnections. System reliability studies of a composite generation and transmission system containing a DC link involve modelling the DC transmission line and then analysing the overall composite system with the DC link forming an integral part. This paper illustrates a technique for DC system reliability analysis using the Monte Carlo simulation approach. The procedure developed was tested on a model DC system and the results are presented. The basic MECORE program was extended to include a DC link within composite generation-transmission system adequacy assessment. This paper also presents the Monte Carlo techniques employed for the composite system study and the results obtained for the modified IEEE-RTS (Reliability Test System)     

Effects of storage and homogenization methods on the hepatic recovery of dextrans determined by size-exclusion chromatography

The effects of storage and homogenization methods on the analytical recovery of dextran macromolecules from rat livers were investigated using a high-performance size-exclusion chromatographic (HPSEC) method. Livers were collected from rats dosed with fluorescein-labeled dextrans with molecular weights of 150 or 70 kD. Subsequently, the livers were subjected to different methods to study the effects of the following parameters on the hepatic recovery of dextrans: storage method (freezing the livers before homogenization or freezing the homogenates); contents of the homogenization buffer (addition of 1% Triton X-100); and sample type (HPSEC analysis of the whole homogenate or the supernatant after centrifugation). It is shown that in the absence of Triton in the homogenization buffer, the hepatic recovery of dextrans is substantially affected by all the factors studied. However, in the presence of 1% Triton in the buffer, the hepatic recoveries were maximal and independent of the storage method or sample type. These studies suggest that for optimal recovery of dextran macromolecules from the liver, a sample preparation method capable of disrupting the subcellular membranes should be used.     

WIPL: a program for electromagnetic modeling of composite-wire andplate structures

WIPL is a program which allows fast and accurate analysis of antennas. The geometry of any metallic structure (even a very large structure) is defined as a combination of wires and plates. WIPL's analysis features include evaluations of the current distribution, near and far field, and impedance, admittance and s-parameters. The program uses an entire-domain Galerkin method. Efficiency of the program is based on the flexible geometrical model, and sophisticated basis functions. In this paper, the basic theory implemented in the program, and some results concerning TV UHF panel antennas and large horn antennas are given     

Malacoplakia of the prostate and seminal vesicle. Ultrastructural study and review of the literature

OBJECTIVES: The present study describes a case of malacoplakia of the genitourinary tract arising in the seminal vesicle and prostate and reviews similar cases previously reported in the literature. METHOD: A 67-year-old male consulted for hemospermia and voiding symptoms. Prostatic neoplasm was suspected on the basis of the clinical and radiological findings. RESULTS: The diagnosis was made only after biopsy and histological analysis. Electron microscopy is a very useful tool. Long-term antibiotic therapy may achieve optimal results. Treatment with fluoroquinolones was successful. CONCLUSION: To avoid unwarranted radical approaches, we underscore the possibility that prostatic pseudotumors may be misinterpreted as neoplasia. Malacoplakia is diagnosed only by histology and requires medical treatment.     

Visualization of plasma turbulence

We have developed a three-dimensional toroidal gyrokinetic particle simulation to study tokamak turbulence. The gyrokinetic equations are a reduced set derived from the Vlasov-Maxwell equations by phase averaging over the ion gyromotion and keeping only the time and space scales relevant for describing tokamak plasmas. These large-scale simulations in complex geometry can produce gigabytes of data consisting of large 3D arrays evolving in time. Visualization plays a critical role in going from the raw nonlinear solution of these complex equations to a simplified theoretical model explaining the essential underlying physics     

Design and simulation of waveguide electrooptic beam deflectors

Numerical simulation based on the scalar beam propagation method, was used to investigate the performance of waveguide electrooptic beam deflectors. The deflectors under investigation consist of a stack of electrooptically controlled prisms in a waveguide. The results were compared to earlier simplified analysis. It was found that for given overall device dimensions, the number of interfaces between prisms in a prism-type electrooptic deflector has significant influence on the device performance when it is small. To avoid wavefront distortion, unwanted reflection from the interfaces, and asymmetry in the deflection angles caused by small number of interfaces, one should use more than about ten interfaces in a typical deflector. Additional insights of device operation and design issues are discussed     

Eco-energetic analysis of village ecosystem of different traditional societies of Northeast India

The village ecosystem functions of the Nishis, Karbis, Kacharis and Chakmas of Arunachal Pradesh in north-east India have been compared. Shifting cultivation is practised alone by the Nishis under different cycle lengths with maximum energy and economic efficiencies obtained under a 10-year cycle. The Karbis obtained maximum energy and monetary outputs per ha from valley cultivation because of more intensive cultivation than that practised by the Nishis. The energy and monetary outputs of mustard cultivation on flatlands and kitchen gardens were lowest among the agro-ecosystems. From an eco-energetic perspective, the cattle and mithun of the Nishis are more efficient than the swine and poultry of other tribes. The forest is closely linked with agriculture and animal husbandry and provides fodder, fuelwood, food for humans, and timber. The efficiency of the village ecosystem as a whole was best for the Nishis, who obtained greater self-sufficiency through recycling of resources.