Ni–Fe Catalysts Based on Perovskite-type Oxides for Dry Reforming of Methane to Syngas

LaNi_(1−x)Fe_xO₃ (x=0, 0.2, 0.4 and 0.7) perovskite-type catalysts were modified by the partial substitution of nickel by iron, aiming to increase the stability and resistance to carbon deposition during the methane dry reforming reaction. The results showed that a suitable combination of precipitation and calcination steps could result in oxides with the desired structure and with improved properties from the point of view of heterogeneous catalysis. The partial substitution of Ni by Fe in the perovskite structure resulted in decreasing rates of conversion of both reactants. However, the stability of the catalyst during the reaction was highly increased. These substituted catalysts were shown to be stable and the LaNi_0.8Fe_0.2O₃ catalyst, calcined at 800 °C for 5 h, was the most active in the reaction conditions.     

Graph-theoretic and energetic exploration of catalytic pathways of the water-gas shift reaction

The catalytic mechanisms or pathways of water-gas shift (WGS) reaction have been the focus of intense research interest because of its immense importance in hydrogen production. At the outset, 116 stoichiometrically feasible independent pathways (IP_i's) have been exhaustively generated within 2 s on a PC through a novel graph-theoretic method based on P-graphs (process graphs) from a set of 17 plausible elementary reactions. This is followed by the determination of IP₁₈ among these 116 stoichiometrically feasible IP_i's as the plausibly dominant pathway via energetic analysis.     

Simple Energy-Based Method for Nonlinear Analysis of Incompressible Pile Groups in Clays

This note presents a method for predicting nonlinear response of pile groups in clays, subjected to vertical loads. The method is based on mobilizable strength design (MSD) concepts, in which the mobilized strength is associated with the shear strains developed in the soil. The suggested procedure is incremental, and requires evaluation of a displacement field. A simple procedure of superposition of pattern functions is suggested for the construction of a complete displacement field. The incremental procedure allows for the variation of the displacement field throughout the loading process, according to principles of minimum energy and compatibility requirements among the piles. Essentially, the procedure allows consideration of a nonlinear continuum between the piles. The pattern functions are an adaptive form of the logarithmic function suggested by Randolph and Wroth in 1979. Under small load levels, when the soil is essentially elastic, the procedure yields values comparable to those from the elastic solution of Randolph and Wroth. At larger strain levels, nonlinear pile group response is simulated based on the soil constitutive models specified by the practitioner. The method is applicable to cases where shaft loading does not induce volume changes in the soil. The method is compared with three dimensional finite difference simulation of undrained loading of pile groups with a nonlinear soil constitutive model. Fair agreement is observed.     

Centralised urban wastewater reuse: what is the public attitude?

Public support is crucial for successful implementation of wastewater reuse projects. This paper analyses the findings of a questionnaire-type survey (256 participants) conducted to determine the attitude of Israeli urban public towards possible urban reuse options. The paper summarises the support/objection to 13 reuse options and the correlation between support and environmental awareness and perceptions. Results show that a high proportion of the participants supported options perceived as low-contact, such as irrigation of public parks (96%), sidewalk landscaping (95%) and use in the construction industry (94%), while higher-contact reuse options found less support (e.g. commercial launderettes, 60%). No correlation was found between biographical characteristics and support (education, gender, income, age). Based on the results, public campaigns in Israel should focus on disseminating information regarding wastewater treatment technologies, discuss health related issues, highlight the positive economic impact of water reuse and generate a positive public opinion, as these factors tend to influence individuals to support reuse projects.     

Seamless image stitching by minimizing false edges.

Various applications such as mosaicing and object insertion require stitching of image parts. The stitching quality is measured visually by the similarity of the stitched image to each of the input images, and by the visibility of the seam between the stitched images. In order to define and get the best possible stitching, we introduce several formal cost functions for the evaluation of the stitching quality. In these cost functions the similarity to the input images and the visibility of the seam are defined in the gradient domain, minimizing the disturbing edges along the seam. A good image stitching will optimize these cost functions, overcoming both photometric inconsistencies and geometric misalignments between the stitched images. We study the cost functions and compare their performance for different scenarios both theoretically and practically. Our approach is demonstrated in various applications including generation of panoramic images, object blending and removal of compression artifacts. Comparisons with existing methods show the benefits of optimizing the measures in the gradient domain.     

Toxins and Biologically Active Secondary Metabolites of Microcystis sp. isolated from Lake Kinneret

For many years cyanobacteria were considered a minor, negligible component of the phytoplankton population in Lake Kinneret (Sea of Galilee, Israel). However, during the last decade several new species invaded the lake and other, more common species were present more frequently and in higher concentrations. Recently, we isolated two Microcystis sp. strains from Lake Kinneret. Both produced an array of hepatotoxic microcystins. In a bioassay-guided study we identified in exudates of one of the Microcystis strains (MB-K) that allelopathic activity was attributed to a novel metabolite, microcarbonin A ( 1 ). Subsequently, two other novel metabolites, micropeptin KT946 ( 2 ) and anabaenopeptin KT864 ( 3 ), were isolated from the hydrophilic extract of the cultured (MB-K) strain, based on their protease inhibition activity. Homo- and heteronuclear-2D-NMR techniques, as well as HRMS, determined the gross structure of the three compounds. The relative and absolute stereochemistry of 2 and 3 was deduced from a combination of spectral data and Marfey's method for HPLC.     

Three-Dimensional Analysis of Lateral Pile Response using Two-Dimensional Explicit Numerical Scheme

A procedure for exploiting a two-dimensional (2D) explicit, numerical computer code for the 3D formulation of dynamic lateral soil-pile interactions is considered. The procedure is applied to two models using simultaneous computation of a series of plane strain boundary value problems, each of which represents a horizontal layer of soil. The first model disregards the shear forces developed between the horizontal layers, and may be considered as a generalized Winkler model. The second model takes account of these forces by coupling the behavior of the horizontal layers. Several verification problems for a single pile and pile groups in a homogeneous soil layer modeled as a viscoelastic material were solved and compared to known solutions in order to assess the reliability of the models. Excellent agreement was observed between results of the present analyses and existing solutions.     

Upper Bound for Cylinder Movement Using “Elastic” Fields and Its Possible Application to Pile Deformation Analysis

A new upper bound failure mechanism for the problem of rigid cylinder motion is presented. The velocity field associated with the mechanism is derived from a known elastic solution by similitude of the deformation field. The obtained upper bound value is 21% higher than the exact solution. However, the failure mechanism is continuous, involving no discontinuity, not even on the cylinder perimeter. The solution has a certain advantage if one, for example, wishes to combine its mechanism with a strain path approach to investigate the T-bar penetration problem. The absence of discontinuities in the mechanism also allows evolution of deformation under serviceability conditions, by associating a mobilized strength as a function of an average strain. Based on this approach, a load transfer function for lateral loading of piles in an undrained clay is suggested. This load transfer function involves nonlinear scaling of a stress-strain curve obtained from a triaxial compression test. An analytical, closed form, solution is given for the case of a hyperbolic stress-strain curve.     

The effect of faulty construction on building maintenance

Saudi Arabia is a rich developing country with huge capital resources and is developing quickly in every area, including building construction. Public and private sectors have initiated large and complex construction projects on tight completion deadlines which in some cases have led to errors and defects occurring that will result in later high maintenance costs.     

The quest for runware: on compositional, executable and intuitive models

We believe that future models of complex software and systems will combine the crucial traits of intuitiveness, compositionality, and executability. The importance of each of these to modeling is already well recognized, but our vision suggests a far more powerful synergy between them. First, models will be aligned with cognitive processes used by humans to think about system behavior and will be understood, and perhaps creatable, by almost anyone. Second, one will be able to build models incrementally, adding to, refining or sculpting away already-specified behaviors without changing most existing parts of the model. Third, there will be powerful ways to execute such intuitive and compositional models, in whole or in part, at any stage of the development. The presence of these three traits in a single artifact will blur the boundaries between natural-language requirements, formal models, and actual software, bringing in its wake a major advance in the way systems are built, and in their cost and quality. We propose the term runware to refer to this kind of higher level artifact.