Solution-processed polymer–silver nanowire top electrodes for inverted semi-transparent solar cells

We present a transparent, fully solution-processed top anode system comprising a thin, conductive polymer interlayer below a silver nanowire mesh for efficient organic electronic devices. We fabricate inverted semi-transparent polymer solar cells exhibiting power conversion efficiencies that are comparable to devices incorporating an opaque electrode. By means of scanning electron microscopy and light beam induced photocurrent measurements we show that the thin polymer interlayer facilitates charge extraction from the active layer and efficient transport to the metallic nanowire mesh.     

The role of the polymer solid electrolyte molecular weight in light-emitting electrochemical cells

Different molecular weights (M_w) of poly (methyl methacrylate) (PMMA) were used as the base for the polymer solid electrolyte (PSE) in light-emitting electrochemical cells (LECs). The rheological properties of the LECs formulations are influenced by the M_w of PMMA. The M_w of PMMA also influences the PSE ionic conductivity and therefore affects the threshold voltage of the devices. Furthermore, partial segregation of the two polymers is observed, which correlates directly to the PMMA M_w. The device with the best performance was prepared with a PMMA M_w of 350,000 and exhibited an effective maximum luminance ～3000 cd m^?2.     

Compositional evolution of the emplaced fuel source in the vadose zone field experiment at Airbase Verløse, Denmark

A field experiment was performed in a sandy vadose zone, studying the fate of an emplaced fuel-NAPL source, composed of 13 hydrocarbons and a tracer. The UNIFAC model was used to testthe nonideal behavior of the source, and the numerical model MIN3P was used for assessing the effect of biodegradation on source evolution. The diffusive loss to the surrounding vadose zone and the atmosphere created temporary gradients in mole fractions of the individual compounds within the source NAPL. The evolution of the source composition corresponded in general with expectations based on Raoult's Law, with the exception thatthe mole fractions of aromatic compounds in the source NAPL decreased faster than fractions of aliphatic compounds of similar volatility. Calculation of activity coefficients (y) using the UNIFAC model implied nonideal conditions, with composition-dependent gammas different from 1. Positive deviations were calculated for the aromatic compounds. The effect of biodegradation on source depletion, evaluated by numerical modeling, was greater for the aromatic as compared to the aliphatic compounds. Hence, the faster depletion of the aromatic relative to aliphatic compounds of similar volatility is both a result of the nonideality of the mixture and a result of partitioning and biodegradation in the pore-water. Vapor concentrations of the compounds in the source were in reasonable agreement with predictions based on the modified Raoult's Law with the UNIFAC predicted gammas and the NAPL composition for the most volatile compounds. For the less volatile compounds, the measured vapor concentrations were lower than predicted with the largest deviations for the least volatile compounds. This field experiment illustrated that nonideal behavior and bioenhanced source depletion need to be considered at multicomponent NAPL spill sites.     

Improved CD control and line edge roughness in E-beam lithography through combining proximity effect correction with gray scale techniques

A proximity effect correction (PEC) technique for E-beam lithography is presented which overcomes hardware limitations of many older E-beam writers regarding the number of physical dose classes by a unique combination of gray scale techniques with PEC using the Layout BEAMER software. The benefit is not only an improvement in critical dimension control, but also an improvement in line edge roughness (LER). Compared to standard PEC techniques the percentage line width deviation has been dramatically reduced by more than a factor of three.     

Mossgas “gas-to-liquid” diesel fuels—an environmentally friendly option

This paper presents a brief summary and comparison of heavy vehicle emissions using Mossgas synthetically derived diesel as opposed to a US Regular Federal 49-state number 2 diesel fuel. A series of engine dynamometer and heavy-duty chassis dynamometer tests were performed at West Virginia University early in 1999.

The Mossgas gas-to-liquid (GTL) low sulphur diesel fuel is produced primarily by the conversion of olefins to distillate (COD) process in conjunction with a high temperature Fisher–Tropsch technology process.

Findings were that there were significant emission benefits when using Mossgas GTL diesel fuel. Oxides of nitrogen (NO_x) and particulate matter (PM) emissions were substantially lower when compared to normal fossil fuel-derived diesel. Additionally the benefits have been found to cut across different engine technologies, various test cycles, engine age (1991–1999), as with or without engine aftertreatment catalysts.

The Mossgas GTL diesel meets the world-wide challenge to produce environmentally friendly transportation fuels and sets the benchmark for future diesel specifications. Accordingly Mossgas has petitioned the US Department of Energy to register this fuel as an alternative fuel under its EPACT program [1 and 2].     

General quantitative specification theories with modal transition systems

This paper proposes a new theory of quantitative specifications. It generalizes the notions of step-wise refinement and compositional design operations from the Boolean to an arbitrary quantitative setting. Using a great number of examples, it is shown that this general approach permits to unify many interesting quantitative approaches to system design.     

A probabilistic dynamic technique for the distributed generation of very large state spaces

Conventional methods for state space exploration are limited to the analysis of small systems because they suffer from excessive memory and computational requirements. We have developed a new dynamic probabilistic state exploration algorithm which addresses this problem for general, structurally unrestricted state spaces.

Our method has a low state omission probability and low memory usage that is independent of the length of the state vector. In addition, the algorithm can be easily parallelised. This combination of probability and parallelism enables us to rapidly explore state spaces that are an order of magnitude larger than those obtainable using conventional exhaustive techniques.

We derive a performance model of this new algorithm in order to quantify its benefits in terms of distributed run-time, speedup and efficiency. We implement our technique on a distributed-memory parallel computer and demonstrate results which compare favourably with the performance model. Finally, we discuss suitable choices for the three hash functions upon which our algorithm is based.