A robust predictive model for base shear of steel frame structures using a hybrid genetic programming and simulated annealing method

This study presents a new empirical model to estimate the base shear of plane steel structures subjected to earthquake load using a hybrid method integrating genetic programming (GP) and simulated annealing (SA), called GP/SA. The base shear of steel frames was formulated in terms of the number of bays, number of storey, soil type, and situation of braced or unbraced. A classical GP model was developed to benchmark the GP/SA model. The comprehensive database used for the development of the correlations was obtained from finite element analysis. A parametric analysis was carried out to evaluate the sensitivity of the base shear to the variation of the influencing parameters. The GP/SA and classical GP correlations provide a better prediction performance than the widely used UBC code and a neural network-based model found in the literature. The developed correlations may be used as quick checks on solutions developed by deterministic analyses.     

DLS: A dynamic local stitching mechanism to rectify transmitting path fragments in wireless sensor networks

In this paper, a pair of novel rectification algorithms (greedy negative pressure push algorithm and dynamic local stitching algorithm) is proposed to cooperatively repair broken transmitting paths in Wireless Sensor Networks. Our approach is to overcome the poor data validity in WSNs, specifically for harsh application environments – such as unattended sensor nodes or frail wireless transmitting channels – where fault tolerant becomes a vital aspect. Using adjacency information, Greedy negative pressure push algorithm can efficiently grow the transmitting path to achieve the minimum energy consumption for relays model. Here, we measured packet travel time and the expectation of relay distance to set this model's key parameters to achieve the lowest possible end-to-end transmitting delay. Dynamic local stitching algorithm has a major difference with other existing routing algorithms in rectifying broken paths; despite others that reroute whole paths, our algorithms only stitch broken fragments of the original path spending minimum amount of energy as well as recovery time. Based on mathematical computing and simulation, our novel rectification algorithm could effectively (1) reduce the total number of routing overheads, (2) improve net throughput, and (3) increase system fault tolerant much better than four already designed routing algorithms. Results were also very promising to motivate other algorithms in this field.     

Performance evaluation of a continuous flow Photo-Impinging Streams Cyclone Reactor for phenol degradation

In this study, an impinging streams cyclone reactor has been utilized as a novel apparatus in photocatalytic degradation of phenol. Degussa P25 TiO₂ nano particles have been applied as the photocatalyst under UV radiation. The operating parameters including catalyst loading, pH, initial phenol concentration and light Intensity have been found to affect the efficiency of the photocatalytic degradation process within this photoreactor. Photocatalytic degradation of phenol has been also investigated in a continuous flow impinging streams system. The results have shown a higher efficiency and an increased performance capability of the present reactor in comparison with the conventional processes.     

Drying and conservation conditions of pollen

In this study, drying and conservation conditions of pollens (for Anzer Honey) were experimentally investigated, and the general drying curve equation was derived by applying the Least Squares Method. Drying experiments were conducted in solar‐ and electric‐assisted dryers. Pollens were placed on the shelves as 50 each g in a single layer having a depth of 2.5 mm. During the drying experiments, the shelf temperatures of the drying cupboard were regulated between 40 °C and 45 °C. Weight losses, moisture contents and mass shrinkage of pollens and average temperatures in the shelves were determined and calculated based on drying time. Additionally, the experimental uncertainty values were calculated as approximately 18%, depending on the experimental results. It was concluded that pollens should be dried at temperatures between 40 °C and 45 °C for between 2.5 and 3 h so as not to change the colour, flavour, smell and structure, and conserved in brown bottles under vacuum in a shady medium. © 2000 Society of Chemical Industry     

Stability and convergence of F iterative scheme with an application to the fractional differential equation

In this paper, we prove that F iterative scheme is almost stable for weak contractions. Further, we prove convergence results for weak contractions as well as for generalized non-expansive mappings due to Hardy and Rogers via F iterative scheme. We also prove that F iterative scheme converges faster than the some known iterative schemes for weak contractions. An illuminative numerical example is formulated to support our assertion. Finally, utilizing our main result the solution of nonlinear fractional differential equation is approximated.

     

A spatially explicit model of postdisaster housing recovery

Although postdisaster housing recovery is an important player in community recovery, its modeling is still in its infancy. This research aims to provide a spatial regression model for predicting households’ recovery decisions based on publicly available data. For this purpose, a hierarchical Bayesian geostatistical model with random spatial effects was developed. To calibrate the model, households’ data that were collected from Staten Island, New York, in the aftermath of Hurricane Sandy were used. The model revealed that on the scale of census tract, residents with higher income or larger household size were significantly less likely to reconstruct. In contrast, odds of reconstruction rose with increase of long‐term residents. The model outputs were also employed to develop a reconstruction propensity score for each census tract. The score predicts probability of reconstruction/repair in each tract versus others. The model was validated through comparison of the propensity scores with the distribution of Community Development Block Grant Disaster Recovery assistance and its resultant reconstruction. The validation indicated capability of the model to predict the potential hotspots of reconstruction. Accordingly, the propensity score can serve as a decision‐support tool to tailor recovery policies.     

Template synthesis of novel monolayer B4C ultrathin film

The excellent physical and chemical properties of two-dimensional (2D) ultrathin film of boron carbide (B₄C) make it suitable for various applications. Nonetheless, the related fabrication strategies have not been well established yet. In this paper, the branches of dendritic magnesium oxide (MgO) nanofibers have been firstly used to serve as the template for synthesis of high-quality monolayer B₄C ultrathin film. As a thermal source, DC arc-discharge plasma was adopted to co-evaporate the raw mixture target comprising of boron, graphite and magnesium oxide species. In the evaporation and subsequent condensation processes, the scaffolds of crossed MgO nanofibers were built at higher temperature prior to heterogeneous nucleation of B₄C nanosheets on them. It is indicated that the kneaded B₄C films can wrap MgO nanofibers into a round-shaped sphere and were entirely stretched out by removal of MgO scaffolds through a simple water-washing purification. The monolayer B₄C ultrathin film is about 1.5?nm in thickness and several micrometers in length. UV–vis diffuse reflectance spectra reveal that the band gap of B₄C films is ~1.37?eV, which is around 50% higher than that of normal B₄C films. This work describes the formation mechanism of such monolayer B₄C ultrathin film in aspect of nucleation/growth processes under the high-temperature plasma conditions.     

Field emission study of carbon nanotubes forest and array grown on Si using Fe as catalyst deposited by electro-chemical method

Vertically aligned carbon nanotubes are synthesized by Low Pressure Chemical Vapor Deposition (LPCVD) on Si substrate coated with Fe as a catalyst at a pressure of 20 Torr and at a growth temperature of 600 degrees C. The catalyst film is prepared by electro-chemical method which is very unique and a low cost method. Three precursor gases Acetylene (C2H2), Ammonia (NH3) and Hydrogen (H2) at the flow rate of 20 sccm, 100 sccm and 100 sccm respectively are allowed to flow through the Low Pressure Chemical Vapor Deposition reactor for 10 minutes. Scanning Electron Microscope (SEM) images show that synthesized CNTs are vertically aligned and uniformly distributed with a high density. Raman analysis shows G-band at 1574 cm(-1) and D-band at 1370 cm(-1). The G-band is higher than D-band, which indicates that CNTs are highly graphitized. The field emission measurement reveals good field emission properties of as-grown vertically aligned carbon nanotubes with turn-on field of 1.91 V/microm at the current density 10 mA/cm2. The field enhancement factor is calculated to be 7.82 x 10(3) for as-grown carbon nanotubes.     

Effect of reinforcement on plastic shrinkage and settlement of self-consolidating concrete as repair material

The experimental investigation on plastic shrinkage and plastic settlement for different self-consolidating concrete (SCC) mixtures as repairing materials is presented. The concrete mixtures were placed on the surface of the concrete substrate slabs at different restraint degrees. Four different types of repairing materials such as plain SCC, SCC with silica fume (SF), SCC with latex and SF, and SCC with latex, SF and fiber were evaluated. The slabs included both reinforcement and without reinforcing bars. The tests involved measurement of concrete bleeding and evaporation rates, steel bar strains and crack characteristics. The results indicated that bleeding rate is not the only controlling factor, but restraint condition, configuration of steel bars and the concrete strain capacity are also affect plastic shrinkage and settlement behaviors significantly. Latex and fiber were found to be effective in reduction of cracks and concrete strains. Cracks did not develop on the surface of concrete containing latex and fiber. The results showed that if a slab is reinforced by one single bar (in each direction of the slab), at relatively large diameter as used in this study, it would not improve the plastic shrinkage behavior, although it causes plastic settlement cracking.