Fabrication of novel light-emitting devices based on green-phosphor/conductive-polymer composites

We report on light-emitting devices based on a green-phosphor compound (Mn-doped zinc silicate, Zn2SiO4: Mn) dispersed in a conductive polymeric blend (poly-o-methoxyaniline/polyvinylene fluoride, POMA/PVDF-TrFE). The devices exhibited high luminance in the green, good stability and homogeneous brilliance over effective areas up to 5 cm(2). The electroluminescence (EL) spectrum presented essentially the same characteristics as the photoluminescence (PL) and cathodoluminescence spectra, indicating that the light emission originates from decay of the same excited species, regardless of the excitation source. Operating characteristics were analyzed with current density - voltage (J - V) and luminance voltage ( L - V) curves to investigate the nature of the electroluminescence of the active material, which is still not completely understood.

Infrared emission and defect centres in Er and Yb codoped Y(3)Al(5)O(12) phosphors

YAG phosphor powders doped/codoped with Er(3+)/(Er(3+) + Yb(3+)) have been synthesised by using the solution combustion method. The effect of direct pumping into the (4)I(11/2) level under 980 nm excitation of doped/codoped Er(3+)/Yb(3+)-Er(3+) in Y(3)Al(5)O(12) (YAG) phosphor responsible for an infrared (IR) emission peaking at similar to 1.53 mu m corresponding to the (4)I(13/2)->(4)I(15/2) transition has been studied. YAG exhibits three thermally-stimulated luminescence (TSL) peaks at around 140A degrees C, 210A degrees C and 445A degrees C. Electron spin resonance (ESR) studies were carried out to identify the centres responsible for the TSL peaks. The room temperature ESR spectrum of irradiated phosphor appears to be a superposition of two distinct centres. One of the centres (centre I) with principal g-value 2.0176 is identified as O(-) ion, while centre II with an isotropic g-factor 2.0020 is assigned to an F(+) centre (singly ionised oxygen vacancy). An additional defect centre is observed during thermal-annealing experiments and this centre (assigned to F(+) centre) seems to originate from an F-centre (oxygen vacancy with two electrons) and these two centres appear to correlate with the observed high-temperature TSL peak in YAG phosphor.

Sustained high levels of foliar herbivory of the mangrove Rhizophora stylosa by a moth larva Doratifera stenosa (Limacodidae) in north-eastern Australia

The moth larva, Doratifera stenosa (Lepidoptera: Limacodidae), was observed feeding voraciously in great numbers on mature leaves of Rhizophora stylosa in mangroves at Port Curtis in Central Queensland, NE Australia. This behaviour was considered unusual since mangroves, and the Rhizophora species in particular, reportedly harbour few herbivores and have relatively low levels of herbivory, less than 10%. During a two year period (1996-1998), larvae were observed consuming around 30-40% of leaves in the canopy each year, and the mangroves appeared able to sustain these high levels of herbivory. The impact on trees was assessed in conjunction with a study of the herbivore, its behaviour and life history, in an attempt to explain the occurrence. Larvae were 1-2 cm in length, bright green and gregarious, with numerous small, stinging hairs along their upper bodies. Feeding was in small cohort groups of 5-70 individuals that broke up immediately prior to each moult after which they regrouped in much larger numbers of mixed cohorts to form single-file processions across branches, stems and prop roots. In this way, they moved to neighbouring trees with less affected foliage. One of the outstanding characteristics of this herbivore was its ability to desist from killing host trees although it appeared quite capable of doing so had it remained on individual trees. By moving from tree to tree, the herbivore was able to heavily crop Rhizophora foliage in an apparently sustainable manner. These findings demonstrate the role and importance of foliar herbivory in severely affected forests and how such instances best not be ignored or treated as curiosities in future assessments of herbivory and forest turnover in mangrove ecosystems.

Design and development of an LED based fiber optic evanescent wave sensor for simultaneous detection of chromium and nitrite traces in water

The design and development of a cost-effective, simple, sensitive and portable LED based fiber optic evanescent wave sensor for simultaneously detecting trace amounts of chromium and nitrite in water are presented. In order to obtain the desired performance, the middle portions of two multimode plastic clad silica fibers are unclad and are used as the sensing elements in the two arms of the sensor. Each of the sensor arms is sourced by separate super bright green LEDs, which are modulated in a time-sharing manner and a single photo detector is employed for detecting these light signals. The performance and characteristics of this system clearly establish the usefulness of the technique for detecting very low concentrations of the dissolved contaminants.

Protesto contra maquiagem verde do carbono

Atores ativistas protestam durante o Bright Green - a feira de tecnologia em Copenhague - ironizando as soluções de baixo carbono como instrumentos para se manter o mesmo padrão de consumo que levou o planeta à crise do clima

Linhagens de alface crespa resistentes a Bremia lactucae e interação genótipo x ambiente

Pós-graduação em Agronomia (Genética e Melhoramento de Plantas) - FCAV

A NEW “PAROTRAP” ADAPTED FROM THE MAC TRAP FOR CAPTURING LIVE PARAKEETS IN THE FIELD

The Rose-ringed parakeet (Psittacula krameri [Scopdi]) has been reported (Roberts, 1974; Bashir, 1978; Beg, 1978; and DeGrazio, 1978) as a serious bird pest of maize, sunflower, rape seeds, and fruit crops, particularly citrus, mangoes, and guavas, in Pakistan. Estimated annual losses to maize grown for seed alone amount to about 97,000 tons, worth about Pak. Rs. 150 million or US $15 million (Roberts, 1978). Paradoxically, this handsome bright green parakeet is highly esteemed in the pet trade; and limited numbers are also marketed locally and sometimes exported to neighboring countries, particularly the Arab Gulf Emirates, as caged pets. Traditional control methods aimed at scaring or chasing birds from the crops, usually with noise-making devices, are costly; furthermore, they have largely been unsuccessful and time consuming because they require human patrolling before and after normal working hours. They provide at best only temporary relief. The aim of this study was to develop a new decoy trap based on the Modified Australian Crow Trap (MAC), which we propose to call the PAROTRAP, and to evaluate its effectiveness and potential in capturing live parakeets in the field as a possible solution to the parakeet problem, as well as promoting the economic exploitation of trapped parakeets for the pet trade. The study was undertaken during March and June 1979 as a part of the UNDP/FAO Project No. PAK/71/554, assisting Pakistan Vertebrate Pest Control Centre in developing and improving control techniques to prevent or reduce bird damage to important crops. Our earlier trials showed that parakeets could be induced to enter a conventionally designed MAC trap, and that after some time they learned how to escape from it. Therefore, a series of minor modifications were introduced and field tested.

Table 2: Evaporation from individual shoots of antarctic mosses

Experimental observations on pathways of water movement are discussed in relation to anatomical and micromorphological features of five moss species from Signy Island, South Orkney Islands. Significant internal uptake of water was recorded only in the mesic species Polytrichum alpinum (internal=>60% of total) and Bartramia patens (internal=c.30% of total), in experiments in which uptake by cut shoots was compared in individuals with the external pathway blocked, and others with both external and internal pathways open. Internal uptake maintained shoot water content close to full turgor in P. alpinun and at 30% of full tugor in B. patens, whereas water content fell to 12-15% dry wt. in the lithophytes Andreaea gainii and Schistidium antarctici and in the mesic/hydric species Drepanocladus uncinatus, with the external pathway blocked. Where both pathways were open water uptake from below maintained water content at or above full turgor in shoots of all five species. External water uptake by capillarity occurred most rapidly in the lithophytes, and was slower in initially air-dry than in hydrated shoots of the other species. The spreading limbs of leaves in B. patens and P. alpinum are water-repellent, as are the bright green leaves in the apical 1-2 mm of dry shoots of the lithophytes. A central strand of hydroids is well-developed only in B. patens and P. alpinum. These two species have deposits of surface wax on parts of the leaves, and surface wax also occurs on the green apical leaves in some specimens of S. antarcticum and other lithophytes from Signy Island.

Highly efficient electro-gene therapy of solid tumor by using an expression plasmid for the herpes simplex virus thymidine kinase gene

We report successful electro-gene therapy (EGT) by using plasmid DNA for tumor-bearing mice. Subcutaneously inoculated CT26 tumor was subjected to EGT, which consists of intratumoral injection of a naked plasmid encoding a marker gene or a therapeutic gene, followed by in vivo electroporation (EP). When this treatment modality is carried out with the plasmid DNA for the green fluorescent protein gene, followed by in vivo EP with the optimized pulse parameters, numerous intensely bright green fluorescent signals appeared within the tumor. EGT, by using the “A” fragment of the diphtheria toxin gene significantly inhibited the growth of tumors, by about 30%, on the flank of mice. With the herpes simplex virus thymidine kinase gene, followed by systemic injection of ganciclovir, EGT was far more effective in retarding tumor growth, varying between 50% and 90%, compared with the other controls. Based on these results, it appears that EGT can be used successfully for treating murine solid tumors.

The shoes of happiness, and other poems;

"The poems in this volume have appeared in various American and English periodicals."--Publisher's note.

Optimizing the Synthesis of AZN

Azulenyl nitrone (AZN) is a bright green compound that can be used to stain different compounds, including plastics. When these stained plastics are irradiated, as they commonly are in the sterilization of medical devices, AZN changes color from green to red, constituting a permanent change. This would make obsolete the current methods of radioactive labeling and maintain the integrity of medical equipment. Although a method of synthesis is already in place, the aim was to improve the yield significantly and find a more efficient and cost-effective procedure. Last year, the procedure used resulted in 18 to 20% of AZN synthesized at the most favorable conditions. With that in mind, this year modifications were done in the hopes of improving the yield. The solvent was changed to a mixture of isopropanol and triethylamine, a stronger base, and a catalytic amount of N-tertbutyl hydroxylamine hydrochloride was used (around 4 equivalents). The reaction time was also increased to 7 days, rather than 2. After several trials, the samples were run through column chromatography and the average yield was 70%, a much more promising result than that obtained last year. There is still research to be done to improve the technicalities of the procedure, including altering the amounts of N-tertbutyl hydroxylamine hydrochloride to try and obtain similar data with fewer amounts. This portion of the research will be done in the second half of the year. In the meantime, however, a novel and more efficient method of synthesis has been established for the production of AZN that can be potentially commercialized.

Optimizing the Synthesis of AZN

Azulenyl nitrone (AZN) is a bright green compound that can be used to stain different compounds, including plastics. When these stained plastics are irradiated, as they commonly are in the sterilization of medical devices, AZN changes color from green to red, constituting a permanent change. This would make obsolete the current methods of radioactive labeling and maintain the integrity of medical equipment. Although a method of synthesis is already in place, the aim was to improve the yield significantly and find a more efficient and cost-effective procedure. Last year, the procedure used resulted in 18 to 20% of AZN synthesized at the most favorable conditions. With that in mind, this year modifications were done in the hopes of improving the yield. The solvent was changed to a mixture of isopropanol and triethylamine, a stronger base, and a catalytic amount of N-tertbutyl hydroxylamine hydrochloride was used (around 4 equivalents). The reaction time was also increased to 7 days, rather than 2. After several trials, the samples were run through column chromatography and the average yield was 70%, a much more promising result than that obtained last year. There is still research to be done to improve the technicalities of the procedure, including altering the amounts of N-tertbutyl hydroxylamine hydrochloride to try and obtain similar data with fewer amounts. This portion of the research will be done in the second half of the year. In the meantime, however, a novel and more efficient method of synthesis has been established for the production of AZN that can be potentially commercialized.

Effect of chlorine concentration on the spectral characteristics of electroluminescence in ZnS: Cu: Cl phosphor

ZnS: Cu: Cl phosphor prepared under a vacuum firing process is found to give blue electroluminescence with emission peak at 460 nm which remams unaltered with the frequency of the excitation voltage. Addition of excess chlorine in the phosphor gives blue, green and red emission at 460, 520 and 640 run. The intensity of the blue band decreases and It fmally disappears as chlorine concentration is increased. A scheme involving three energy levels attributed to Cu2+, Cu+ and Cl- centres in Zns explains the experimental results completely.

The evolution of green leases: towards inter-organizational environmental governance

Improving the environmental performance of non-domestic buildings is a complex and ‘wicked’ problem due to conflicting interests and incentives. This is particularly challenging in tenanted spaces, where landlord and tenant interactions are regulated through leases that traditionally ignore environmental considerations. ‘Green leasing’ is conceptualized as a form of ‘middle-out’ inter-organizational environmental governance that operates between organizations, alongside other drivers. This paper investigates how leases are evolving to become ‘greener’ in the UK and Australia, providing evidence from five varied sources on: (1) UK office and retail leases, (2) UK retail sector energy management, (3) a major UK retailer case study; (4) office leasing in Sydney, and (5) expert interviews on Australian retail leases. With some exceptions, the evidence reveals an increasing trend towards green leases in prime offices in both countries, but not in retail or sub-prime offices. Generally introduced by landlords, adopted green leases contain a variety of ambitions and levels of enforcement. As an evolving form of private–private environmental governance, green leases form a valuable framework for further tenant–landlord cooperation within properties and across portfolios. This increased cohesion could create new opportunities for polycentric governance, particularly at the interface of cities and the property industry.