Synergistic effects of buffer layer processing additives for enhanced hole carrier selectivity in inverted Organic Photovoltaics

Solution based inverted Organic Photovoltaic (OPVs) usually use Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) derivatives combined with pristine processing additives as hole selective contact on top of the hydrophobic conjugated polymer:fullerene active layer. In this study, PEDOT:PSS based hole selective contact is treated with two different boiling point additives, 2,5,8,11-tetramethyl-6-dodecyn-5,8-diol ethoxylate (Dynol) and Zonyl FS-300 fluorosurfactant (Zonyl). Although corresponding inverted OPVs using the above PEDOT:PSS:Additives show similar power conversion efficiency (PCE) values, the mechanisms of their implementation on inverted OPV operation are not identical. By understanding the synergistic effects of PEDOT:PSS processing additives on the hole selectivity of inverted OPVs we demonstrate a novel combination of PEDOT:PSS additives mixture as an effective route to further increase the hole selectivity, reliability andpower conversion efficiency of inverted OPVs.     

Matrix hybridization in the interlayer for carbon fiber reinforced composites

Polymeric composites have gone through a level of maturity beyond the laboratory stage with the development of the Boeing 787, the structure of which contains more than 50% composites. Nonetheless, a basic understanding of the material used in its primary structure has not been extensively investigated. For instance, micromechanical models are inadequate as they always assume an evenly distributed homogeneous matrix, without following classic lamination theory, which assumes constant stress through the laminate thickness. Our program now in its third year at the Polymeric Composites Laboratory in Seattle, supported by industry as well as government agencies, and in collaboration with several universities on a global scale, is developing such concepts for understanding and improving matrices in layered configurations. This effort focuses on the development of interlayer systems used as enablers to improve certain properties of the composite, such as fracture‐toughness and crack‐propagation inhibition. POLYM. COMPOS., 31:1965–1976, 2010. © 2010 Society of Plastics Engineers.     

Experimental and numerical iInvestigations of effects of silica colloids on transport of strontium in saturated sand columns

Transport experiments with strontium were conducted using saturated sand columns in the presence and absence of silica colloids, and numerical modeling was performed with modeling results compared to experimental data. The experiments were aimed at testing the hypothesis that under certain chemical conditions colloids act as movement-retarding agents and yield a larger effective retardation factor for the migrating contaminant. Four individual experiments were conducted to identify conditions where the mobility of silica colloids is increased or decreased, and a similar set was conducted for strontium transport in the absence of colloids. Mobility of colloids was found to increase with decreasing ionic strength and increasing pH, with the ionic strength having the more significant impact. The reverse effect was obtained for strontium. Based on these results, two additional experiments were conducted where both colloids and strontium were injected at the column inlet. Results showed that under certain conditions of ionic strength and pH (I = 3.0 x 10(-2) M and pH = 4-5.4) colloids retarded the movement of strontium. The retardation effect was obtained in two experiments under slightly modified conditions, which confirms the role of colloids as retarding agents. Afinite difference numerical model was used to (a) simulate mobile breakthrough curves and compare to experimental data and (b) estimate the model parameters describing cotransport of strontium and colloids. The model accurately predicted arrival time and the overall shape of the breakthrough curves.     

Photorealistic Large-Scale Urban City Model Reconstruction

The rapid and efficient creation of virtual environments has become a crucial part of virtual reality applications. In particular, civil and defense applications often require and employ detailed models of operations areas for training, simulations of different scenarios, planning for natural or man-made events, monitoring, surveillance, games, and films. A realistic representation of the large-scale environments is therefore imperative for the success of such applications since it increases the immersive experience of its users and helps reduce the difference between physical and virtual reality. However, the task of creating such large-scale virtual environments still remains a time-consuming and manual work. In this work, we propose a novel method for the rapid reconstruction of photorealistic large-scale virtual environments. First, a novel, extendible, parameterized geometric primitive is presented for the automatic building identification and reconstruction of building structures. In addition, buildings with complex roofs containing complex linear and nonlinear surfaces are reconstructed interactively using a linear polygonal and a nonlinear primitive, respectively. Second, we present a rendering pipeline for the composition of photorealistic textures, which unlike existing techniques, can recover missing or occluded texture information by integrating multiple information captured from different optical sensors (ground, aerial, and satellite).     

Studies on the Authenticity of Local Wines by Spectroscopic and Chemometric Analysis

The authenticity of 91 wines produced in Cyprus from both indigenous and other vine varieties were investigated by a holistic approach, using, advanced technology such as SNIF-NMR （site-specific natural isotopic fractionation-nuclear magnetic resonance） and 1R-MS （isotope ratio-mass spectrometry） for the determination of the stable isotopes and ICP （inductively coupled plasma spectroscopy） for some heavy metals. The spectroscopic characteristics were evaluated statistically using different chemometric methods. The dependency of the D/H （deuterium/hydrogen） ratio of the methylene site in the ethanol molecule （D/H）ll and also theδ ^18O values of the wine water, were the most useful discriminators. Isotopic results allow us to have a complete idea about the regional variability of the isotopes. Among the metals, Ni followed by Pb was the ones with the highest discrimination value. The determined concentrations of Pb, Ni, Cr and Cd that are related to the safety of wines were within the acceptable limits that have been established by the OIV （international organization of vine and wine） or comparable with the results of the wines of other European countries. The study of the correlation between the load of heavy metals and isotopes in wines showed a dependence on the grape variety but not the geographical location of the vineyard. This is probably due to the close proximity of wine regions in Cyprus.     

Data Mining techniques for the detection of fraudulent financial statements

This paper explores the effectiveness of Data Mining (DM) classification techniques in detecting firms that issue fraudulent financial statements (FFS) and deals with the identification of factors associated to FFS. In accomplishing the task of management fraud detection, auditors could be facilitated in their work by using Data Mining techniques. This study investigates the usefulness of Decision Trees, Neural Networks and Bayesian Belief Networks in the identification of fraudulent financial statements. The input vector is composed of ratios derived from financial statements. The three models are compared in terms of their performances.     

The linkage between reporting quality and performance in IS projects

Recent research has suggested that flawed status reporting is a serious concern in IS projects. However, the linkage between reporting quality and project performance has not been empirically confirmed. Our investigation consisted of two complementary studies, both of which employed previously validated measures of reporting quality and project outcomes. The first considered the perceptions of 210 IS project members of the quality of status reports they submitted to their project managers. The second considered the perceptions of 485 IS project managers of the quality of project reports they received from project members reporting to them. Both showed that the perceived quality of project reporting was less than perfect and was significantly associated with project task and psychological outcomes. Moreover, the second study results suggested that reporting quality was also related to organizational outcomes. We offer recommendations for project managers.     

Metal ion sorption and desorption on zeolitized tuffs from the Nevada Test Site

Because of the hundreds of nuclear weapon tests conducted on the Nevada Test Site (NTS) during the Cold War, the migration of radionuclides and contaminants is a potential concern. The mobility of these compounds and our ability to remediate contaminated sites are controlled by sorption and desorption processes, which depend frequently on the nature of the contaminant, the mineralogy of the site, and the geochemical conditions. The sorption and desorption behavior of strontium (Sr) and lead (Pb), two metal cations with different chemistries, commonly found on nuclear test sites were studied. Strontium showed pH-independent and ionic-strength-dependent sorption, consistent with ion exchange processes at permanent charge sorption sites. The sorption uptake of Sr increased with decreasing ionic strength of background solution. Strontium desorption from the adsorbents was enhanced by increased background electrolyte concentration and was a function of background electrolyte composition. The fractional uptake of Pb was higher, compared to that of Sr, and was only pH dependent at the highest ionic strength used (1.0 M). This pH-dependent sorption behavior, consistent with formation of surface complexes at amphoteric surface hydroxyl sites or formation of surface precipitates, could explain the decreased Pb desorption, compared to that of Sr, especially at increased background electrolyte concentrations. Under conditions typical for the groundwater at the NTS (I = 0.003 M, pH = 8.0), both Pb and Sr are expected to bind strongly on tuffs with composition similar to the zeolitized tuffs used in this study. Any increase in the dissolved ion concentration of the groundwater, however, may result in, at least partial, release of Sr and enhanced Sr mobility.     

Supercritical carbon dioxide extraction of okra (Hibiscus esculentus L) seeds

Pilot‐scale supercritical fluid extraction of okra seeds was carried out, using carbon dioxide as solvent, at temperatures of 40, 50 and 60 °C and pressures of 150, 300 and 450 bar. Laboratory‐scale Soxhlet extraction of the ground seeds was carried out with ethanol and n‐hexane. The yields of supercritical fluid extraction and n‐hexane Soxhlet extractions were similar. The ethanol Soxhlet extraction gave the highest yield, but the concentrations of β‐sitosterol and tocopherols in this extract were lower than in the supercritical fluid extraction product. The fatty acid profiles of the extracts were determined, and a high unsaturated/saturated ratio was observed. The fatty acid compositions were only slightly different for oils obtained by the different extraction methods. Copyright © 2005 Society of Chemical Industry     

LQG optimality and separation principle for general discrete time partially observed stochastic systems over finite capacity communication channels

This paper is concerned with control of stochastic systems subject to finite communication channel capacity. Necessary conditions for reconstruction and stability of system outputs are derived using the Information Transmission theorem and the Shannon lower bound. These conditions are expressed in terms of the Shannon entropy rate and the distortion measure employed to describe reconstruction and stability. The methodology is general, and hence it is applicable to a variety of systems. The results are applied to linear partially observed stochastic Gaussian controlled systems, when the channel is an Additive White Gaussian Noise (AWGN) channel. For such systems and channels, sufficient conditions are also derived by first showing that the Shannon lower bound is exactly equal to the rate distortion function, and then designing the encoder, decoder and controller which achieve the capacity of the channel. The conditions imposed are the standard detectability and stabilizability of Linear Quadratic Gaussian (LQG) theory, while a separation principle is shown between the design of the control and communication systems, without assuming knowledge of the control sequence at the encoder/decoder.