Solution-processed LiF for work function tuning in electrode bilayers

Although ambient processing is the key to low-cost organic solar cell production, high-vacuum thermal evaporation of LiF is often a limiting step, motivating the exploration of solution processing of LiF as an alternative electrode interlayer. Submonolayer films are realized with the assistance of polymeric micelle reactors that enable LiF particle deposition with controlled nanoscale surface coverage. Scanning Kelvin probe reveals a work function tunable with nanoparticle coverage with higher values than that of bare indium tin oxide (ITO).     

Influence of annealing duration on the erosive wear behavior of polyphenylenesulphide composites

The influence of annealing duration on the erosive wear behavior of short glass fiber (40% w/w) and CaCO₃ mineral particulate (25% w/w)–short glass fiber (40% w/w) (total: 65% w/w) reinforced PPS composites has been characterized under various experimental conditions by differential scanning calorimetry (DSC) and erosion measurements. The erosive wear of the composites have been evaluated at different impingement angles (30, 45, 60, and 90°) and at four different annealing periods (30, 60, 90, and 120 min). Increase in the total crystallization causes an improvement in the erosive wear properties of the samples. Annealing time controls the morphology by influencing the degree of crystallinity in the matrix and in the fiber–matrix interface. This formation restricts fiber–matrix debonding. There is no linear proportionality between annealing time and relative degree of crystallization. The results indicate that PPS composites show maximum in wear versus impact angle relation at 60° confirming their semi-ductile failure behavior. The morphologies of eroded surface are examined by the scanning electron microscope.     

Optimization of the Pore Structures of MOFs for Record High Hydrogen Volumetric Working Capacity

Metal–organic frameworks (MOFs) are promising materials for onboard hydrogen storage thanks to the tunable pore size, pore volume, and pore geometry. In consideration of pore structures, the correlation between the pore volume and hydrogen storage capacity is examined and two empirical equations are rationalized to predict the hydrogen storage capacity of MOFs with different pore geometries. The total hydrogen adsorption under 100 bar and 77 K is predicted as n_tot= 0.085× V_p − 0.013× V_p² for cage-type MOFs and n_tot= 0.076× V_p − 0.011× V_p² for channel-type MOFs, where V_p is the pore volume of corresponding MOFs. The predictions by these empirical equations are validated by several MOFs with an average deviation of 5.4%. Compared with a previous equation for activated carbon materials, the empirical equations demonstrate superior accuracy especially for MOFs with high surface area (i.e., S_BET over ≈3000 m² g⁻¹). Guided by these empirical equations, a highly porous Zr-MOF NPF-200 (NPF: Nebraska Porous Framework) is examined to possess outstanding hydrogen total adsorption capacity (65.7 mmol g⁻¹) at 77 K and record high volumetric working capacity of 37.2 g L⁻¹ between 100 and 5 bar at 77 K.     

Incremental construction of classifier and discriminant ensembles

We discuss approaches to incrementally construct an ensemble. The first constructs an ensemble of classifiers choosing a subset from a larger set, and the second constructs an ensemble of discriminants, where a classifier is used for some classes only. We investigate criteria including accuracy, significant improvement, diversity, correlation, and the role of search direction. For discriminant ensembles, we test subset selection and trees. Fusion is by voting or by a linear model. Using 14 classifiers on 38 data sets, incremental search finds small, accurate ensembles in polynomial time. The discriminant ensemble uses a subset of discriminants and is simpler, interpretable, and accurate. We see that an incremental ensemble has higher accuracy than bagging and random subspace method; and it has a comparable accuracy to AdaBoost, but fewer classifiers.     

Ordering and finding the best of K > 2 supervised learning algorithms

Given a data set and a number of supervised learning algorithms, we would like to find the algorithm with the smallest expected error. Existing pairwise tests allow a comparison of two algorithms only; range tests and ANOVA check whether multiple algorithms have the same expected error and cannot be used for finding the smallest. We propose a methodology, the multitest algorithm, whereby we order supervised learning algorithms taking into account 1) the result of pairwise statistical tests on expected error (what the data tells us), and 2) our prior preferences, e.g., due to complexity. We define the problem in graph-theoretic terms and propose an algorithm to find the "best" learning algorithm in terms of these two criteria, or in the more general case, order learning algorithms in terms of their "goodness." Simulation results using five classification algorithms on 30 data sets indicate the utility of the method. Our proposed method can be generalized to regression and other loss functions by using a suitable pairwise test.     

Wind turbine power curve estimation based on cluster center fuzzy logic modeling

Wind energy applications and turbine installation at different scales have been increased for last decade. Technically wind turbine capacity has been improved at high levels. However, electricity could not be generated at all stages of wind speed and so there are some limits related to cut-in and cut-out data. One of the main problems in wind engineering is to estimate output data of wind turbines depends on wind speed and system values. Wind speed problematic values, that are less than cut-in and greater than cut-out, take the most important role for estimating wind power curve models. All wind turbines have different cut-in and cut-out limits and generating of electricity could be achieved in a certain interval that could be called as affective interval. Fuzzy logic that is a new and novel verbal logical approach has many applications in the field of engineering. Cluster center fuzzy logic modeling is also a new and the effective method in this scientific area. In this paper, the first power curve of a wind turbine is modeled by least square methodology. After that depending on the fuzzy logic approach a new application is realized. It is seen that, this curve type could be well represented and modeled by the clustering center fuzzy logic modeling than classical least square methodology. It is estimated that four or five cluster centers are enough for representing wind turbine power curve by running proposed method.     

Rapid Transmutation of High-Level Nuclear Wastes in a Catalyzed Fusion-Driven System

The aim of this study is to investigate the high-level waste (HLW) transmutation potential of fusion-driven transmuter (FDT) based on catalyzed D–D fusion plasma for various fuel fractions. The Minor actinide (MA) (²³⁷Np, ²⁴¹Am, ²⁴³Am and ²⁴⁴Cm) and long-lived fission product (LLFP) (⁹⁹Tc, ¹²⁹I and ¹³⁵Cs) nuclides discharged from high burn-up pressured water reactor-mixed oxide spent fuel are considered as the HLW. The volume fractions of the MA and LLFP are raised from 10 to 20% stepped by 2% and 10 to 80% stepped by 5%, respectively. The transmutation analyses have been performed for an operation period (OP) of up to 6 years by 75% plant factor (η) under a first-wall neutron load (P) of 5 MW/m² by using two different computer codes, the XSDRNPM/SCALE4.4a neutron transport code and the MCNP4B Monte Carlo code. The numerical results bring out that the considered FDT has a high neutronic performance for an effective and rapid transmutation of MA and LLFP as well as the energy generation along the OP.     

CHEMICAL CHARACTERISTICS OF SUPERCRITICAL TOLUENE EXTRACTS FROM TWO TURKISH LIGNITES

Samples from two major deposits of Turkish lignites were subjected to supercritical toluene extraction at 325°C and 14.1 MPa in an autoclave. The resultant extracts were separated into pre-asphaltene, asphaltene, saturates, aromatics and resin fractions by column chromatography. The fractions were characterized by ¹H-NMR, ¹³C-NMR, IR. and elemental analysis in order to compare the chemical composition of extracis from the two coal samples. The results show that the extracts from the Tungbiiek (T-coal) deposits contain aliphatic constituent which is composed of mostly long chain unbranched alkyl compounds while the extracts from the Soma Mcrkeg (S-coal) deposits contain a significant amount of branched paraffinic compounds. The resin fractions from both samples were found to contain a significant amount of single ring aromatic compounds.     

PETROLEUM AT THE ROOF OF THE WORLD: The geological evolution of the Tibet (Qinghai-Xizang) Plateau Part I

The Tibet (Qinghai-Xizang) Plateau is underlain by many thousands of mters of Ordovician (and possibly Cambrian) through Middle Eocene, gently-dipping, essentially undeformed, stable platform sequences. These are largely qf shallow-water, marine-shelf origin in the Ordovician-Triassic sections, but are of mixed continental and marine facies in the Jurassic through Midle Eocene sections. Two east-west fault troughs - the Banggong Co - Nu Jianand Indus River -Yarlung Zangbo - contain thick sections of Triassic, Jurassic, and/or Cretaceous marine flysch associated with ophiolites. The only severe deformation to affect the plateau was during the Mesozoic, and it was concentrated close to the through-going east-west fractures. Post-early Eocene beds are entirely continental, and are concentrated nsmall-to-large grabens. One of these, the Lunpola Basin, has been moderately explored. Drilling here during the 1970s recovered small amounts of heavy, biodegraded oil of non-marine origin, from a sectionthat ranges in age from Middle Eocene through Quaternary Plateau-wide stratigraphic studies reveal that the Ordovician through Early Carboniferous, and Late Permian through Middle Eocene, sections were deposited on a monolithic stable block. All were deposited in essentially warm tropical seas in close proximity, as demonstrated by the, facies, faunas, and floras. These same studies, plus related tectonic investigations, reveal that the through-going east-west fracture zones, popularly interpreted as “sutures,” are not sutures at all. Rather, the facies belts in rocks of all ages studied in detail routinely cross the so-called “sutures,” commonly at very sharp angles, proving that these east-west fault zones exerted no control overthe general lithofacies deposition patterns of the Himalaya-Tibet block. The oniy facies control exerted by the fracture zones was in the small, narrow troughs that developed along them. Thus, the Himalaya-Tibet block behaved as a single structural unit through time, and was never segmen red in to various microcontinents. Although some potential for commercial petroleum discoveries exists in the post-middleEocene grabens. the greatest potential of the Himalaya-Tibet block is in the Paleozoic-Mesozoicsection. with its promise of multiple source-beds. reservoirs, traps, and seals. We predict that, one day, this “roof of the world” will host many petroleum Jields.