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.     

RF plasma modified W5O14 and MoS2 hybrid nanostructures and photovoltaic properties

Modification of W₅O₁₄ and MoS₂ nanostructures was carried out using 3,4-ethylenedioxythiophene monomer in a capacitively coupled, RF rotating plasma reactor. Raman spectroscopy and X-ray diffraction (XRD) measurements were used for structural characterization. The surface morphologies of nanomaterials were investigated using transmission electron microscopy. Polymer coated (W₅O₁₄/PEDOT, MoS₂/PEDOT) and untreated (W₅O₁₄, MoS₂) nanostructures were used as the counter electrode for dye-sensitized solar cells. Photovoltaic performances of W₅O₁₄/PEDOT and MoS₂/PEDOT hybrid nanostructures were higher than those of W₅O₁₄ and MoS₂ inorganic nanostructures. Our results indicate that plasma polymer coated W₅O₁₄ and MoS₂ nanostructures of the device for cathode increase both its fill factor and its energy conversion efficiency.     

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.     

Bipedal robot walking control on inclined planes by fuzzy reference trajectory modification

The two-legged humanoid structure has advantages for an assistive robot in the human living and working environment. However, the control of bipedal walk is a challenge. Walking performance on solely even floor is not satisfactory. This paper presents a study on bipedal walk on inclined planes with changing slopes. A Zero Moment Point (ZMP) based gait synthesis technique is employed. The pitch angle reference for the foot sole plane—as expressed in a coordinate frame attached at the robot body—is adjusted online by a fuzzy logic system to adapt to different walking surface slopes. Ankle pitch torques and the average value of the body pitch angle, computed over a history of a predetermined number of sampling instants, are used as the inputs to this system. The proposed control method is tested via walking experiments with the 29 degrees-of-freedom human-sized full-body humanoid robot SURALP (Sabanci University Robotics Research Laboratory Platform) on even floor and inclined planes with different slopes. The results indicate that the approach presented is successful in enabling the robot to stably enter, ascend and leave inclined planes with 15?% (8.5°) grade. This, to the best knowledge of the authors, constitutes the steepest ascend reported to date, with a transition from even floor, by a blind walking biped robot.     

Rough-Set-based timing characteristic analyses of distance protective relay

Nowadays protection engineers are suffering from very complex implementations of protection system analysis due to massive quantities of inconsistent data, let alone coming from diverse intelligent electronic devices (IEDs). Thus, a novel Rough-Set-based data mining strategy has been formulated to resolve the inconsistency in a distance protective relay's decision system (i.e. a transformed relay event report) in such a way that the relay's timing characteristics hidden in its decision algorithm of protection operations have been successfully discovered. Using Rough Set Theory, the inherent uncertainty and vagueness in the relay event report have been resolved using the concepts of discernibility, elementary sets and set approximations. The timing characteristics that have been successfully discovered are in relation to the relay trip assertion activity, impedance element activation, fault characteristics, circuit breaker operation and its overall decision system approximation.     

Expansion of a static analysis-based out-of-plane maximum inelastic seismic response estimation method for steel arch bridges to in-plane response estimation

We have previously proposed a static analysis-based method for estimating the maximum out-of-plane inelastic seismic response of upper-deck steel arch bridges. The method is developed on the basis of the numerical examinations of 6 upper-deck steel arch bridge models. It employs free vibration analysis, response spectrum method and equal energy assumption for the estimation of maximum out-of-plane response. Correction functions are proposed to modify the estimates by the equal energy assumption. In the current study, applicability of the same procedure to the estimation of maximum in-plane response is discussed. It is found that the method can be used also for the maximum in-plane response estimation by only modifying the pushover analysis procedure. The validity of the method is demonstrated for the same parametric models through further numerical evaluations.     

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.     

Experiences with the Soviet suture stapler SPTU in colon and and rectum surgery. Controlled study of 94 patients

In a controlled study the practicability, tightness of the anastomosis and complications in the p.o. period were analyzed in a total 94 colon and rectum anastomoses by making use of the SPTU-model. 28% of the patients operated in this way were more than 70 years old, the average age came up to 63.3 years. The incidence of anastomotic leakage after low anterior resection was 24% and 5.5% after high anterior resection. 17 per cent of the patients suffered from complications during the postoperative period and 2 patients (2.1 per cent) came to death. The results of 36 high and 58 low anterior resections justify the further use of the SPTU auto-suture apparatus.     

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.