High Efficiency

AbstractÐThe electrochemical compression of hydrogen is well known since years. But new developments of the polymer electrolyte membrane (PEM) fuel cells make it possible to realize the electrochemical compression in a PEM-cell with high eciency. A new cell design of PEM-cells for operation with a high pressure dierence between anode side and cathode side was developed. The puri®cation of hydrogen from carbon monoxide of the reformer gas can be integrated in the hydrogen compressor cell. Operation parameters are presented. #

This paper describes the summary of a three-year development program for the first-stage stationary vane and rotating blade for the next generation, 1500°C class, high-efficiency gas turbine. In such a high-temperature gas turbine, the first turbine vane and blade are the most important hot parts. Full-coverage film cooling (FCFC) is adopted for the cooling scheme, and directionally solidified (DS) nickel base superalloy and thermal barrier coating (TBC) will be used to prolong the creep and thermal fatigue life. The concept of the cooling configuration, fundamental cascade test results, and material test results will be presented.

From 2002 to 2006, a combined R&D project named AQUASOL has been carried out at the facilities of the Plataforma Solar de Almería (Spain). Main objective of this project has been the development of a hybrid solargas desalination system based on multi-effect distillation process that meets at the same time the requirements of low-cost, high efficiency and zero discharge.

We herein describe the synthesis and characterization of nine new 1,3,4-thiadiazolium-2-phenylamine chlorides derived from natural piperine. We evaluate their toxic effects against the different evolutive forms of Trypanosoma cruzi, and the host cell (murine macrophages). The results obtained show that mesoionic hydrochloride MI possesses the best activity profile. Compound MI may be a prototype for use in the development of a new chemotherapeutic agent with high efficiency, which may be employed in the treatment of Chagas' disease.

Efficiency and linearity of the microwave power amplifier are critical elements for mobile communication systems. This paper discusses improvements in system efficiency that are obtainable when a dc-dc converter is used to convert available battery voltage to an optimal supply voltage for the output RF amplifier. A boost dc-dc converter with an operating frequency of 10 MHz is demonstrated using GaAs heterojunction bipolar transistors. Advantages of 10-MHz switching frequency and associated loss mechanisms are described. For modulation formats with time-varying envelope, such as CDMA, the probability of power usage is described. Gains in power efficiency and battery lifetime are calculated. An envelope detector circuit with a fast feedback loop regulator is discussed. Effects of varying supply voltage with respect to distortion are examined along with methods to increase system linearity.

Purpose -The aim of the research was to evaluate the concept that utilizes structured planar substrates based on low temperature co-fired ceramics (LTCC) as a precision platform for the passive alignment of a multimode fiber and wide-stripe diode laser. Design/methodology/approach -Presents the manufacturing process for realisation of 3D precision structures, heat dissipation structures and a cooling channel into the LTCC substrate. The developed methodology for 3D modelling and simulation of the system was used to optimize structures, materials and components in order to achieve optimal performance for the final product and still maintain reasonably low fabrication costs. The simulated optical coupling efficiency and alignment tolerances were verified by prototype realization and characterization. Findings -The achieved passive alignment accuracy allows high coupling efficiency realisations of multimode fiber pigtailed laser modules and is suitable for mass production. Research limitations/implications -Provides guidance in the design of LTCC precision platforms for passive alignment and presents a hybrid simulation method for photonics module concept analysis. Practical implications -The three-dimensional shape of the laminated and fired ceramic substrate provides the necessary alignment structures including holes, grooves and cavities for the laser to fiber coupling. Thick-film printing and via punching can be incorporated in order to integrate electronic assemblies directly into the opto-mechanical platform. Originality/value -Introduces the LTCC 3D precision structures for photonics modules enabling passive alignment of multimode fiber pigtailed laser with high efficiency optical coupling. Demonstrates the hybrid simulation methodology for concept analysis.

Purpose: To develop an optimal nonviral aerosol formulation for locoregional treatment of early lung cancer. Experimental Design: The formulation was made of polylysine/protamine combination (AND) as the carrier and p53 gene (p53sm) as therapeutic agent. To estimate the aerosol deposition, the aerodynamic size of the AND-p53sm was measured with extrusion-precipitation method. To accurately determine the dose, the aerosol efficiency in mice was measured with a fluorescent dye. The transfection efficiency and DNA protection function of the aerosolized formulation in cultured cells and mouse lungs were detected with reporter gene assays and/or reverse transcription-PCR.The preclinical safety and efficacy of AND-p53sm were studied in healthy mice and mice bearing orthotopic human non^small-cell lung cancer (NSCLC) xenograft. Results: After aerosolization, AND is 3-to 17-fold more effective than commonly used PEI or cationic lipid formulations in transfecting the NSCLC cells (relative light units, 1,494 versus 534 and 86; P < 0.003). Aerodynamic size of AND-p53sm ranged 0.2 to 3 Am is the optimal aerosol droplets for deposition in the entire human respiratory tract. Significant gene expression was detected in the lungs of mice given aerosolized AND-p53sm and AND-luciferase. Aerosolized AND-p53sm significantly prolonged the life of mice bearing orthotopic human NSCLC xenografts, and it was more effective than an optimal i.v. cisplatin chemotherapy (increased life span, 93% versus 25%; P = 0.014). Inhalation of AND produced low and reversible pulmonary toxicity and no systemic toxicity. Conclusions: This optimal formulation is suitable for delivering biological materials to human lung with aerosol administration. This therapeutic strategy is an option for patients with early lung cancer and bronchoalveolar carcinoma.

High Impedance Faults (HIF) are faults of difficult detection and location while using traditional digital relaying. In this article it is presented a new proposal for detection and location of HIF's in distribution systems with distributed generation (DG), based on artificial neural networks. The methodology inputs are the local measured voltage and current phase components, supplying as output the detection, classification and location of the fault, when it occurs. The basic characteristics, the algorithm and comparative tests with other detection and location methodologies are presented in this article. The proposed scheme was tested in a simulation platform of a distribution system with DG. The comparative results of the technique with usual fault detection and location schemes show the high efficiency and robustness of the method.

Degradable polymer Biocompatibility a b s t r a c t The focus of this work was to develop potentially biodegradable, polycationic gene carriers possessing high efficiency for gene delivery and being essentially non-toxic. A library of 37 soluble polycations was synthesized by oligomerization of low molecular weight oligoamines with three different crosslinkers, dithiobis-succinimidyl proprionate, dimethyl dithiobis-propionamidate, and hexanediol diacrylate. The types of oligoamine and crosslinker influenced biophysical properties such as DNA binding, hemolytic and endosomolytic membrane activity, transfection efficiency and cytotoxicity of the gene carrier. Degradability of polymers based on reductive cleavage of disulfide bonds or ester hydrolysis was demonstrated. Within the library, oligoethylenimine (800 Da)-based polymers showed the highest gene transfer efficiencies and exceeded the golden standard linear polyethylenimine (22 kDa) in terms of activity/toxicity profile.

This paper focuses on the metal-organic vapor-phase epitaxy growth of 3-junction (3J) solar cells where the epitaxial Ga 0.44 In 0.56 P top and Ga 0.92 In 0.08 As middle subcells are grown lattice-mismatched on a Ge substrate. Single-junction metamorphic devices with 8% and 12%-In, GaInAs are grown on 100 mm dia. (0 0 1) Ge substrates and evaluated in comparison to approximately lattice-matched GaAs and Ga 0.99 In 0.01 As subcells. Layers are observed to be nearly 100% relaxed by high-resolution X-ray diffraction. Threading dislocation densities of B2 Â 10 5 cm À2 in the 8%-In layers are observed by electron beam induced current and cathodoluminescence. Single-junction devices show a constant offset between open-circuit voltage and bandgap of B380 mV. Building upon these results, 3J metamorphic Ga 0.44 In 0.56 P/ Ga 0.92 In 0.08 As/Ge solar cells are fabricated. Very high performances of small area devices are reported with 28.8% efficiency under the AM0 spectrum and 31.3% efficiency under the AM1.5G 1-sun terrestrial spectrum. r

Potential of plants to remove radionuclides/toxic elements from soils and solutions can be successfully applied for removal of important radionuclides such as strontium-90 (90Sr) and cesium-137 (137Cs). When uptake of 137Cs and 90Sr by Calotropis gigantea plants incubated in distilled water spiked with the radionuclides either alone or in combination was studied, it was found to have a high efficiency for the removal of 90Sr, with 90% being removed from solutions (5 × 103 kBq l−1) within 24 h of incubation. However, in case of 137Cs, about 44% could be removed from solutions (5 × 103 kBq l−1) at the end of 168 h of incubation. Accumulation of 90Sr and 137Cs was higher in roots compared to shoots. The plants could remediate both 90Sr and 137Cs when they were added together to the solution. When two months old plants were incubated in low level nuclear waste, 99% of activity disappeared at the end of 15 days. The present study suggests that C. gigantea could be used as a potential candidate plant for phytoremediation of 90Sr and 137Cs.

The efficient use of the power budget in small satellite applications is of primary importance because of the reduced size of the power sources. Unfortunately, high efficiency in power amplifiers (PA) is strongly related to non-linearities and hence distortion. In this paper a digital architecture for the linearization of switched mode PAs is implemented, and a circuit to detect the phase shift and the CORDIC algorithm to correct that phase as well as to compute the magnitude are developed. The results show that linearity is improved by 20 dB for a system with a bandwidth of 9.6 kHz for a loop gain of 10 and 400 ns of system delay. The circuit, implemented in a FPGA consumes a total of 33.3 mW.

INTRODUCTION The spatial resolution of magnetic resonance spectroscopic imaging (MRSI) is typically coarse (e.g., 1 cm^3 voxels), mainly due to SNR limitations. However, the increased signal available with higher field scanners and new array coils now permits higher spatial resolution than is feasible with conventional chemical shift imaging (phase encoding) within the time available in a clinical MRSI exam. More efficient data acquisition methods are required. The use of time varying gradients during the readout window is a well known method for reducing the scan time, with some of the spatial encoding done at the same time as the spectral readout [1]. While some of these methods are sensitive to conditions encountered in practice (timing errors, eddy currents etc.) or require a sophisticated data reconstruction, the "flyback" echo-planar trajectory [2] is particularly insensitive to errors and provides data that are simple to process. Recent advances in gradient hardware have made flyback trajectories feasible with the higher spatial resolutions and larger spectral bandwidth of high-field MRSI. In this abstract we present the design of flyback echo-planar trajectories that make full use of the gradient performance available with a modern, whole-body MRI system. THEORY The readout gradient for a flyback echo-planar trajectory consists of a flat section during which data are acquired, followed by a rewind lobe that retraces across the desired portion of k-space as quickly as possible. The most efficient form of such a gradient consists of rewind lobes using the maximum slew rate of the gradient hardware, interleaved with flat portions that exactly cover the desired extent in k-space. The duration (and thus amplitude) of this flat part is determined by the desired spectral bandwidth (SBW), with SBW = 1/(T_flat + T_rewind). Since data are not acquired during the rewind lobe of the flyback gradient, a penalty in SNR is incurred relative to the usual continuous sampling during the readout window. This penalty, expressed as the fraction of the full SNR that could be achieved during the same readout time, is given by SNRf = (T_flat/(T_flat + T_rewind))

Efficient management of mass algal cultures requires appreciation of the most important factors governing the light regime of the average cell, i.e. the interrelationships between the intensity of the light source -never the sole factor involved in mass culture productivity -and the optimal cell density affected by the optical path. The latter is a dominant factor in photosynthetic productivity of ultra high cell density cultures (UHDC) cultured in flat plate reactors. Indeed, a very short optical path (5-10 mm) permits a most efficient use of strong light by facilitating ultra-high cell densities (ca. 10-20 g dry cell mass l −1 ), in which the condensed cells are exposed to very high frequency light/dark cycles. Another important feature of dense cultures concerns the very small but highly efficient light dose available to cells under extreme mutual shading. The low productivity of the single cell in the culture is well compensated, in terms of culture productivity, by the high culture cell mass exposed to very high frequency light/dark cycles. The combined effects of all these factors result in high efficiency of strong light-use for photosynthesis. UHDC are associated with growth inhibition which represents a severe production obstacle. Once this aspect is better understood and managed, UHDC in ultra short optical path reactors may become a useful production mode of photoautotrophic cell mass and secondary metabolites.

A new gasdynamic launcher is described, in which intact projectiles weighing at least 1 gram can be accelerated to mass velocities of 15-20 km/s. The system employs a conventional 2-stage light gas gun, with the barrel modified and filled with helium to act as a pump tube for a third stage. The key feature of the launcher is that the peak pressure in the third stage can be maintained below 2.5 GPa, thus assuring high efficiency and the integrity of the projectile.

To help ensure the stable long-term operation of a Cherenkov Ring Imaging Detector at high efficiency, a comprehensive monitor and control system is being developed. This system will continuously monitor and maintain the correct operating temperatures, and will provide an on-line monitor of the pressures, flows, mixing, and purity of the various fluids. In addition the velocities and trajectories of Cherenkov photoelectrons drifting within the imaging chambers will be measured using a pulsed UV lamp and a fiberoptic light injection system.

This paper presents a maximum power point tracking (MPPT) controller employing a modified hill top algorithm implemented using embedded microcontroller for solar photovoltaic (PV) module. The proposed MPPT algorithm has high efficiency compared to conventional hill top algorithm in terms of transferring power from source to load. The designed controller regulates the output voltage through control of the DC-DC boost converter under varying environmental conditions. The comparative result for hill top and modified hill top algorithm based on the proposed MPPT controller has been obtained through the simulation studies in PSCAD/EMTDC software. The validity of the proposed modified hill top algorithm has been obtained through experimental implementation of the MPPT controller on a solar PV module driving a load.

A new method to improve the dynamic response of power-factor correctors (PFC's) is described in this paper. The method is based on the use of a new very highly efficient postregulator, called a series-switching postregulator. This new postregulator exhibits very high efficiency due to the fact that only a part of the total power undergoes a power conversion process. The proposed postregulator can be used with any PFC topology (either with or without a transformer), with no modifications in the topology, and can be easily protected against short circuits.

Three alternatives for hydrogen production from solar energy have been analyzed on both efficiency and economic grounds. The analysis shows that the alternative using solar energy followed by thermochemical decomposition of water to produce hydrogen is the optimum one. The other schemes considered were the direct conversion of solar energy to electricity by silicon cells and water electrolysis, and the use of solar energy to power a vapor cycle followed by electrical generation and electrolysis. The capital cost of hydrogen via the thermochemical

The cyclone-type separator with swirling baffle and bottom take off of clean gas is a patented technique for separating solid particles from gases. Main relative dimensions of the separator are the same as given by Stairmand [C.J. Stairmand, The design and performance of cyclone separators, Trans. Inst. Chem. Eng. 29 (1951), 356–383] for the high efficiency cyclone. The principal part of the construction is the cylinder-shape swirling baffle with the flow gaps cut on its surface. The article presents the theoretical model of the new construction of cyclone-type separator with swirling baffle and bottom take off of clean gas. Calculational model to predict the collection efficiency was based on Leith and Licht cyclone calculational method [D. Leith, W. Licht, The collection efficiency of cyclone-type particle collectors — a new theoretical approach, AIChE Symp. Ser. 68 (126) (1972), 196–206]. The main assumption of the developed model is that the tangential velocity distribution is o...

We have characterised a small, high-efficiency diesel generator selected to power remote experiments on the Antarctic plateau at altitudes of up to 5000 m. We describe the design of an environmental chamber to simulate these high altitudes and present an experimental investigation of the engine operation at high altitude on Jet A-1, comparing this to the engine's performance at sea level. Although attention must be paid to the provision of adequate cooling, no modification to the engine itself is required. Our final system provides very high reliability and produces 1500 W of electrical power with a fuel consumption of 280 g kWh À1. A bank of ultracapacitors is used to start the engine in the cold environment of Antarctica. We describe the low-temperature operation and survival tests that we performed on the ultracapacitors and the engine.

Our effort towards the attainment of high performance devices has yielded several devices with total-area conversion efficiencies above 16%, the highest measuring 16.8% under standard reporting conditions (ASTM E892-87, Global 1000 W/m2). The first attempts to translate this development to larger areas resulted in an efficiency of 12.5% for a 16.8-cm2 monolithically interconnected submodule test structure, and 15.3% for a 4.85-cm2 single cell. Achievement of a 17.2% device efficiency fabricated for operation under concentration (22-sun) is also reported. All high efficiency devices reported here are made from graded bandgap absorbers. Bandgap grading is achieved by compositional Ga/(In+Ga) profiling as a function of depth. The fabrication schemes to achieve the graded absorbers, the window materials and contacting are described

Direct injection high efficiency nebulizer (DIHEN)-inductively coupled plasma mass spectrometry (ICPMS) is investigated for analysis of petroleum samples dissolved in volatile organic solvents. To minimize solvent loading, the solution uptake rate is reduced to 10 mlymin, far less than the level (85 mlymin) commonly used for aqueous sample introduction with the DIHEN, and oxygen is added to the nebulizer gas flow and outer flow of the ICP. Factorial design is applied to investigate the effect of nebulizer tip position within the torch and the nebulizer and intermediate gas flow rates on the precision and the net signal intensity of the elements tested for multielemental analysis. Cluster analysis and principal component analysis are performed to distinguish the behavior of different isotopes, oxide species and doubly charged ions. The best operating conditions at a solution uptake rate of 10 mly min are: RF powers1500 W, nebulizer gas flow rates0.10-0.12 lymin, intermediate gas flow rates1.5 lymin and DIHEN tip positions3-4 mm below the top of the torch intermediate tube. Acceptable recoveries (100"10%) and good precision (less than 3% relative standard deviation) are obtained for trace elemental analysis in organic matrices (a certified gas oil sample and a custom-made certified reference material) using flow injection analysis. Because of high blank levels, detection limits are 1-3 orders of magnitude higher for organic sample introduction than those acquired for aqueous solutions. ᮊ

The angular distribution of infrared radiation, emitted by high efficiency single-crystalline silicon solar cells, was analyzed. Measurements were performed on cells with planar and inverted-pyramids surfaces, both showing integral emissions that approach the cosine function in the 0°-90°interval. Textured cell maintains the cosine distribution at the different wavelengths; planar device shows a distribution, which deviates from the cosine function at increasing wavelength. Correspondence between emission and absorption properties was demonstrated valid as a function of emission/ absorption angle. From the angular distribution of electroluminescence light, the devices absorption properties for incident light with directions different from the surface normal were estimated.

In this paper, an active load-pull-based large-signal modeling approach suitable for designing and optimizing Doherty amplifiers is proposed. The optimization of the drive dependant dynamic loads seen by both carrier and peaking amplifier's transistors was carried out using a large-signal load-pull-based behavior model built into CAD software. The latter was also used to optimize the biasing conditions of the peaking and carrier amplifier transistors. The simulation versus measurement results demonstrated the strong ability of the constructed model to predict the nonlinear behavior of 16 watts peak-envelope power designed Doherty amplifier in terms of power added efficiency, AM/AM, and AM/PM distortions.

We have created heralded coherent state superpositions (CSS), by subtracting up to three photons from a pulse of squeezed vacuum light. To produce such CSSs at a sufficient rate, we used our highefficiency photon-number-resolving transition edge sensor to detect the subtracted photons. This is the first experiment enabled by and utilizing the full photon-number-resolving capabilities of this detector. The CSS produced by three-photon subtraction had a mean photon number of 2.75 +0.06 −0.24 and a fidelity of 0.59 +0.04 −0.14 with an ideal CSS. This confirms that subtracting more photons results in higher-amplitude CSSs.

This paper reports on experimental results of aqueous heterophase polymerizations with monomers of quite different solubility in water ranging from the water-soluble 2-hydroxyethyl methacrylate to lauryl methacrylate with solubility in water of only about 10 K4 mM. A calorimetric study revealed the strong influence of both the hydrophilicity of the monomer and the stirrer speed on the rate of polymerization in the absence of surfactants. In order to obtain maximum latex yield and high efficiency (which is a measure considering colloidal properties, polymerization recipe, and polymerization parameters) the initiator-surfactant combination must be properly chosen in dependence on the hydrophilicity of the monomer. Results are presented for sodium alkyl sulfates or disodium-N-stearoyl-L-glutamate as surfactant and potassium peroxodisulfate, or poly(ethylene glycol)-azo-compounds, or 2,2 0-azobis(N-2 0-methylpropanoyl-2-amino-alkyl-1)-sulfonates as initiators.

The elution by characteristic points (ECP) method is a very rapid and precise method for determination of the phase system equilibrium of phase systems in broad solute concentration ranges. Thus, the method is especially suitable for rapid characterization of high efficient separation systems. One important source of error, the effects by the post-loop dispersion, was eliminated in a recent investigation. In this study, the systematic error caused by the selection of the integration starting point at concentration equal to 0 is eliminated. This is done by developing and validating a new procedure for isotherm data generation; the ECP-slope method. The method generates raw slope data of the adsorption isotherm instead of raw adsorption data by integrations as the classical ECP does. Both numerical and experimental data were used for the comparison of the classical ECP approach with the slope-ECP method.

We report highly efficient red phosphorescent organic light-emitting diodes with a triplet p-i-n single quantum well (QW) structure. This p-i-n single QW structure is realized using p-doped and n-doped wide band-gap hole and electron injection and transporting layers with narrow band-gap host and dopant materials. The maximum current and power efficiencies of 11.1 cd/A and 14.4 lm/W, respectively, are demonstrated by a good carrier confinement effect of QW. Very low driving voltage characteristics of 3.7 ∼ 3.9 V at 1000 cd/m2 are realized by almost no injection barrier with high conductivity configuration in our p-i-n structure.

Beam propagation method simulation shows that evanescently coupled waveguide/photodiodes can be optimized to have absorption lengths as short as butt-coupled photodiodes. Efficient focalization of optical power in the absorber is achievable by appropriate choice of layers geometry and refractive index. Two AlGaInAs-GaInAs structures have been designed for ultrawide-band operation at 60 and 100 GHz: these devices exhibit internal quantum efficiency as high as 94% and 75%, respectively, at 1.55-m wavelength. Such promising performances are suitable for the realization of high-speed high-efficiency integrated photoreceivers with applications to millimeter-wave optical fiber links.

Experimental results are reported for a novel four-pole HTS lumped element bandpass Chebyshev ®lter with central frequency 2.25 GHz and 2% fractional bandwidth. High eciency of the substrate area usage is reached by the application of planar coils as inductance elements. Measurements and simulation results are compared and are found to be in satisfactory agreement. Ó

Fusarium oxysporum f. sp. cubense is the causal agent of Panama disease of banana. A rapid and reliable diagnosis is the foundation of integrated disease management practices in commodity crops. For this diagnostic purpose, we have developed a reliable molecular method to detect Foc race 4 isolates in Taiwan. By PCR amplification, the primer set Foc-1/Foc-2 derived from the sequence

In this paper, we investigated the effects of dopants on the electrical and optical characteristics of dichromatic and white organic light-emitting devices (OLEDs) with a double emitting layer (DEML). Such a DEML consisted of two host materials with bipolar transport characteristics doped with two distinct types of phosphorescent emitters. The host for EML1 (adjacent to the anode side) was N,N-dicarbazolyl-3,5-benzene (mCP), with a hole mobility higher than the electron mobility, whereas the host for EML2 (adjacent to the cathode side) was 2,2 0-bis[5-phenyl-2-(1,3,4)oxadazolyl]biphenyl (OXD), with a higher electron mobility than the hole mobility. Phosphorescent blue emitters, 9% iridium(III)bis[4,6di-fluorophenyl-pyridinato-N,C2]picolinate (FIrpic), and phosphorescent green emitters, 9% fac-tris(phenylpyridine) iridium [Ir(ppy) 3 ], were doped into EML1 and EML2, respectively for dichromatic emission. In the dichromatic blue/green OLEDs, both the blue and green dopants helped to reduce the driving voltage. The dopants essentially played the role of carrier traps and recombination centers, from which the current density-voltage characteristics and electroluminescence (EL) spectra were derived. In this structure, EML1 and EML2 exhibited hole-and electron-rich bipolar transporting characteristics, respectively. Hence, the recombination was extended to the two EMLs, which reduced the efficiency roll-off and resulted in high efficiency levels even at high luminance levels. Through further incorporation of 0.5% of tris(2-phenylquinoline)iridium(III) [Ir(2-phq) 3 ] into EML1, a white OLED with maximum current efficiency of 35.8 cd/A and quantum efficiency of 10.73% at 0.643 mA/cm 2 was obtained. In this white OLED, the current efficiency decreased slightly by 2.51% from 35.8 cd/A at 230 cd/m 2 to 34.9 cd/A at 1000 cd/m 2. Carrier confinement was achieved at the D-EML interface, which not only contributed to the high current efficiency, but also resulted in stable color coordinates that varied a mere (À0.014, 0.004) from 100 to 10,000 cd/m 2 , without additional blocking layers between the two EMLs.

In this study, irradiation of natural rubber latex using pulsed plasma cathode electron beam system has been attempted. Fundamentally different from the conventional hot filament electron sources, the present pulsed plasma cathode electron beam can be used for vulcanization process with large area of irradiation (150 × 650 mm), low electrical power consumption (< 9 kW), and high efficiency. The evaluation results show that after electron beam irradiation at 150 kV 18 A on old natural rubber latex with stirring method, an increase of the tensile strength up to 12.3 MPa can be achieved without any chemical additive or sensitizer. Higher tensile strength until 18.0 MPa can be provided on fresh natural rubber latex. It suggests that the present system can be applied as a new type of electron accelerator for cross-linking of natural rubber latex.

We demonstrate high efficiency performance in two ultra-thin, Ge-free III-V semiconductor triple-junction solar cell device designs grown in an inverted configuration. Low-stress metamorphic junctions were engineered to achieve excellent photovoltaic performance with less than 3 x 10 6 cm -2 threading dislocations. The first design with band gaps of 1.83/1.40/1.00 eV, containing a single metamorphic junction, achieved 33.8% and 39.2% efficiencies under the standard one-sun global spectrum and concentrated direct spectrum at 131 suns, respectively. The second design with band gaps of 1.83/1.34/0.89 eV, containing two metamorphic junctions achieved 33.2% and 40.1% efficiencies under the standard one-sun global spectrum and concentrated direct spectrum at 143 suns, respectively.

DNA-based studies have been one of the major interests in conservation biology of endangered species and in population genetics. As species and population genetic assessment requires a source of biological material, the sampling strategy can be overcome by non-destructive procedures for DNA isolation. An improved method for obtaining DNA from fish fins and scales with the use of an extraction buffer containing urea and further DNA purification with phenol-chloroform is described. The methodology combines the benefits of a non-destructive DNA sampling and its high efficiency. In addition, comparisons with other methodologies for isolating DNA from fish demonstrated that the present procedure also becomes a very attractive alternative to obtain large amounts of high-quality DNA for use in different molecular analyses. The DNA samples, isolated from different fish species, have been successfully used on random amplified polymorphic DNA (RAPD) experiments, as well as on amplification of specific ribosomal and mitochondrial DNA sequences. The present DNA extraction procedure represents an alternative for population approaches and genetic studies on rare or endangered taxa.

We present a study of the thermopower S and the dimensionless figure of merit ZT in molecules sandwiched between gold electrodes. We show that for molecules with side groups, the shape of the transmission coefficient can be dramatically modified by Fano resonances near the Fermi energy, which can be tuned to produce huge increases in S and ZT . This shows that molecules exhibiting Fano resonances have a high efficiency of thermoelectric cooling which is not present for conventional un-gated molecules with only delocalized states along their backbone.

The optical properties of a novel potential high-efficiency photovoltaic material have been studied. This material is based on a chalcopyritetype semiconductor (CuGaSa) with some Ga atom substituted by Ti and is characterized by the formation of an isolated transition-metal band between the valence band and the conduction band. We present a study in which ab-initio density functional theory calculations within the generalized gradient approximation are carried out to determine the optical reflectivity and absorption coefficient of the materials of interest. Calculations for the host semiconductor are in good agreement with experimental results within the limitations of the approach. We find, as desired, that because of the intermediate band, the new Ti-substituted material would be able to absorb photons of energy lower than the band-gap of the host chalcopyrite. We also analyze the partial contributions to the main peaks of its spectrum.

a b s t r a c t Thermal silicon oxides are known to very effectively passivate silicon surfaces. Choosing a water vapor ambient instead of a dry oxygen atmosphere increases the oxidation rate by about one order of magnitude and considerably reduces process time and costs. State of the art pyrox systems produce steam by pyrolysis of hydrogen and oxygen gas. A new approach is the purification of vaporized deionized (DI) water. In this work we present a direct comparison of both steam generation systems, which are connected to the same quartz tube of an industrial high quality tube furnace. The higher steam saturation of the direct steam process enhances the growth rate by about 20% compared to a pyrolytic steam based process. On low-resistivity p-type substrates, excellent surface recombination velocities of around 25 cm/s are found for both systems after a forming gas anneal. Detailed characterization shows similar physical properties of the oxide layers grown by either steam from pyrolysis or purified steam. Moreover, thermal oxide rear surface passivated silicon solar cells show similar high efficiencies exceeding 18.0% irrespective of the applied steam generation technology.

As a continuation of our digital X-ray imaging sensor R&D, we have developed a cost-effective, intraoral imaging device based on the complementary-metal-oxide semiconductor (CMOS) photosensor array coupled with an integrated X-ray conversion fiber-optic faceplate. It consists of a commercially available CMOS photosensor of a 35 Â 35 mm 2 pixel size and a 688 Â 910 pixel array dimension, and a high-efficiency columnar CsI(Tl) scintillator of a 90 mm thickness directly deposited on a fiber-optic faceplate of a 6 mm core size and an 1.46 mm thickness with 85/15 core-cladding ratio (NA$1.0 in air). The fiber-optic faceplate is a highly X-ray attenuating material that minimizes X-ray absorption on the end CMOS photosensor array, thus, minimizing X-ray induced noise at the photosensor array. It uses a high light-output columnar CsI(Tl) scintillator with a peak spectral emission at 545 nm, giving better spatial resolution, but attenuates some of this light due to interfacial and optical attenuation factors. In this paper, we presented the performance analysis of the intraoral imaging device with experimental measurements and acquired X-ray images in terms of modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE).

In this work, low temperature Organic Rankine Cycles are studied as bottoming cycle in medium and large scale combined cycle power plants. The analysis aims to show the interest of using these alternative cycles with high efficiency heavy duty gas turbines, for example recuperative gas turbines with lower gas turbine exhaust temperatures than in conventional combined cycle gas turbines. The following organic fluids have been considered: R113, R245, isobutene, toluene, cyclohexane and isopentane. Competitive results have been obtained for toluene and cyclohexane ORC combined cycles, with reasonably high global efficiencies.The paper is structured in four main parts. A review of combined cycle and ORC cycle technologies is presented, followed by a thermodynamic analysis of combined cycles with commercial gas turbines and ORC low temperature bottoming cycles. Then, a parametric optimization of an ORC combined cycle plant is performed in order to achieve a better integration between these two technologies. Finally, some economic considerations related to the use of ORC in combined cycles are discussed.

In this study, performance of a waterworks sludge (FCS: ferric chloride sludge) for the removal of acid red 119 (AR119) dye from aqueous solutions were investigated. For this purpose, response surface methodology (RSM) was applied to optimize three operating variables of coagulation/flocculation process including initial pH, coagulant dosage and initial dye concentration. The results showed that the decrease of initial pH was always beneficial for enhancing dye removal and no re-stabilization phenomenon was occurred even at the used maximum FCS dosage. It seems that iron hydroxides of the FCS could neutralize the negative charges on dye molecules or cause to the trapping of the dye ones. Therefore, the sweep flocculation and/or the charge neutralization might play key roles in the enhancement of dye removal. The optimum initial pH, FCS dosage and initial dye concentration were found to be 3.5, 236.68 mg dried FCS/L and 65.91 mg/L, respectively. Dye removal of 96.53% is observed which confirms close to RSM results. Therefore, it can be concluded that reusing the FCS as a low-cost material into the coagulation/flocculation process in wastewater treatment plants can offer some advantages such as high efficiency for AR119 dye removal and economic savings on overall treatment plant operation costs.