An understanding of the electrodeposition process of Al–Mg alloys using an organometallic-based electrolyte

Al–Mg alloys were deposited using a base-electrolyte with the composition Na[AlEt₄] + 2Na[Et₃Al–H–AlEt₃] + 2.5AlEt₃ + 6toluene (where Et = −C₂H₅). Mg was introduced into this electrolyte by employing a pure Mg anode. It was found that initially the amount of Mg in the electrolyte increased with the deposition time but eventually a steady state was reached such that the amount of Mg dissolved at the anode became equal to that deposited at the cathode. Compositional and phase analyses indicated that this state is achieved at a critical Mg/Al ratio that resulted in the formation of the hcp Mg-rich phase. By devising various component electrolytes we have attempted to understand the roles of different compounds in the base-electrolyte and have proposed a scheme for the Al–Mg alloy deposition.     

A pseudo particle swarm optimization for the RCPSP

In this paper, a pseudo particle swarm optimization (PSO) algorithm is presented to solve the Resource-Constrained Project Scheduling Problem (RCPSP). The proposed algorithm uses the path relinking procedure as a way for the particles in PSO to fly toward local and global best positions. In order to prevent the premature convergence, a mechanism for maintaining the swarm diversity is used. The pseudo PSO algorithm imposes a distance greater than a threshold between the particles in the swarm. The distance threshold is reduced as the iteration number is increased. Extensive computational experiments were executed on standard benchmark problem sets of PSPLIB. The computational results show that the algorithm outperforms all of the other PSO approaches (known by the authors) applied to RCPSP and for the instance set j30, is competitive with the state of the art meta-heuristics.     

Diet, physical activity, and adiposity in children in poor and rich neighbourhoods: a cross-sectional comparison

Background  

Obesity in Canadian children increased three-fold in twenty years. Children living in low-income neighborhoods exercise less and are more overweight than those living in more affluent neighborhoods after accounting for family socio-economic status. Strategies to prevent obesity in children have focused on personal habits, ignoring neighborhood characteristics. It is essential to evaluate diet and physical activity patterns in relation to socio-economic conditions to understand the determinants of obesity. The objective of this pilot study was to compare diet, physical activity, and the built environment in two Hamilton area elementary schools serving socio-economically different communities.     

An experimental investigation of cylindrical wire electrical discharge turning process

The cylindrical wire electrical discharge turning (CWEDT) process was developed to generate precise cylindrical forms on hard, difficult to machine materials. A precise, flexible, and corrosion-resistant submerged rotary spindle was designed and added to a conventional five-axis CNC wire electrical discharge machine (EDM) to enable the generation of free-form cylindrical geometries. The hardness and strength of the work material are no longer the dominating factors that affect the tool wear and hinder the machining process. In this study, the effect of machining parameters on surface roughness (R _a) and roundness in cylindrical CWEDT of a AISI D3 tool steel is investigated. The selection of this material was made taking into account its wide range of applications in tools, dies, and molds and in industries such as punching, tapping, reaming, and so on in cylindrical forms. Surface roughness and roundness are chosen as two of the machining performances to verify the process. In addition, power, pulse off-time, voltage, and spindle rotational speed are adopted for evaluation by full factorial design of experiments. In this case, a 2²?×?3² mixed full factorial design has been selected considering the number of factors used in the present study. The main effects of factors and interactions were considered in this paper, and regression equations were derived using response surface methodology. Finally, the surfaces of the CWEDT parts were examined using scanning electron microscopy (SEM) to identify the macro-ridges and craters on the surface. Cross sections of the EDM parts were examined using the SEM and microhardness tests to quantify the sub-surface recast layers and heat-affected zones under specific process parameters.     

The logical precedence network planning of projects, considering the finish-to-start (FS) relations, using neural networks

One of the important steps in the process of project planning is the designing of logical precedence network. As the procedure of the logical precedence network planning is case dependent and varies in different projects, it could be considered as an unstructured and complex problem which should be solved by implementing the implicit domain knowledge of the planner. In this paper, we have shown how the artificial neural networks could be implemented to plan the finish-to-start logical precedence network of projects. The implementation results depict that the proposed methodology could result reasonable, accurate, and reliable outcomes, which could be used as a primary solution, which can enrich the acquired knowledge, after the accomplishment of the project and its practical corrections.     

Testosterone Reduces Knee Passive Range of Motion and Expression of Relaxin Receptor Isoforms via 5α-Dihydrotestosterone and Androgen Receptor Binding

Ovarian steroids such as estrogen and progesterone have been reported to influence knee laxity. The effect of testosterone, however, remains unknown. This study investigated the effect of testosterone on the knee range of motion (ROM) and the molecular mechanisms that might involve changes in the expression of relaxin receptor isoforms, Rxfp1 and Rxfp2 in the patella tendon and lateral collateral ligament of the female rat knee. Ovariectomized adult female Wistar rats received three days treatment with peanut oil (control), testosterone (125 and 250 μg/kg) and testosterone (125 and 250 μg/kg) plus flutamide, an androgen receptor blocker or finasteride, a 5α-reductase inhibitor. Duplicate groups received similar treatment however in the presence of relaxin (25 ng/kg). A day after the last drug injection, knee passive ROM was measured by using a digital miniature goniometer. Both tendon and ligament were harvested and then analysed for protein and mRNA expression for Rxfp1 and Rxfp2 respectively. Knee passive ROM, Rxfp1 and Rxfp2 expression were significantly reduced following treatment with testosterone. Flutamide or finasteride administration antagonized the testosterone effect. Concomitant administration of testosterone and relaxin did not result in a significant change in knee ROM as compared to testosterone only treatment; however this was significantly increased following flutamide or finasteride addition. Testosterone effect on knee passive ROM is likely mediated via dihydro-testosterone (DHT), and involves downregulation of Rxfp1 and Rxfp2 expression, which may provide the mechanism underlying testosterone-induced decrease in female knee laxity.     

Geometrical and structural setting of landslide dams of the Central Alborz: a link between earthquakes and landslide damming

Bulletin of Engineering Geology and the Environment - The combination of remote sensing observations, geological field investigations and geomorphological mapping and measurements along with faults...     

On the hysteretic behavior of trapezoidally corrugated steel shear walls

At present, corrugated plates have numerous applications such as web of plate girders and aerospace applications. Higher out‐of‐plane stiffness and initial elastic strength of the corrugated plates compared with flat plates are reasons for consideration. This study investigates the behavior of trapezoidally corrugated steel plate shear walls (TCSPSWs) under monotonic and cyclic loadings. Finite element analyses that include both material and geometric nonlinearities are employed for the examination. The results from finite element analysis are verified through tested specimen findings. Moreover, the behavior of the steel shear walls with the flat infill panels and the corrugated plate infill panels is compared. The results show that explicit dynamic analysis is the most suitable analysis for the TCSPSWs under quasi‐static loading. Furthermore, although strength of the TCSPSWs obtained from the finite element analysis and the test are fully coincident in elastic region, nonetheless, they are fairly coincident in elastic–plastic and plastic region. Copyright © 2012 John Wiley & Sons, Ltd.     

The Synthesis and Characterization of Hard-Soft Mn52Al45.7C2.3-α-Fe Nanocomposite Magnets

We report on the magnetic exchange coupling behavior in hard-soft Mn₅₂Al_45.7C_2.3-α-Fe nanocomposite magnets synthesized by high-energy ball milling at room temperature followed by post-annealing treatment at temperatures 300 to 600 °C. The analysis of hysteresis loops showed effective exchange coupling Mn₅₂Al_45.7C_2.3-α-Fe nanocomposite particles with smooth demagnetizing curves when annealed at 400 °C. But higher annealing temperatures pose kink in the hysteresis loop highlighting a weak exchange coupling with more magnetostatic interaction between hard and soft components. This trend was confirmed by the results on (BH)_max, which had the highest value for nanocomposite particles annealed at 400 °C. More detailed information on magnetic exchange coupling in nanocomposite particles was obtained by derivative magnetic curves and Henkel plots. Hard-soft Mn₅₂Al_45.7C_2.3-α-Fe magnets showed the sharpest high-field maximum in derivate magnetic curves when annealed at 400 °C as a signature of effective exchange coupling between Mn₅₂Al_45.7C_2.3 and α-Fe grains. In addition, Henkel plots display the dominance of positive peak for nanocomposite particles annealed at 300 and 400 °C, indicative of magnetic exchange-coupling. But the negative-peak dominated curves of those annealed at higher temperatures as well as single-phase Mn₅₂Al_45.7C_2.3 imply a significant magnetostatic interaction in the components owing to non-magnetic phases formed at elevated temperatures. Also, quantitative information obtained from recoil curve measurements assigned a higher degree of exchange coupling to nanocomposite magnets when annealed at 400 °C.

     

Combined cerium oxide nanocapping and layer-by-layer coating of porous silicon containers for controlled drug release

Local drug release in close vicinity of solid tumors is a promising therapeutic approach in cancer therapy. Implantable drug delivery systems can be designed to achieve controlled and sustained drug release. In this study, ultrathin porous membranes of silicon wafer were employed as compatible drug reservoir models. An anticancer model drug, curcumin (CUR), was successfully loaded into porous silicon containers (8.94?±?0.72% w/w), and then, cerium oxide nanocapping was performed on the open pores for drug protection and release rate prolongation. Next, layer-by-layer surface coating of the drug container with anionic (alginate) and cationic (chitosan) polymers rendered pH-responsivity to the device. The drug release profile was studied using reflectometric interference Fourier transform spectroscopy at different pH conditions. It was determined that faster decomposition of the polymeric layers and subsequent CUR release occur in acidic buffer (pH 5.5) compared to a neutral buffer. Various characterization studies, including dynamic light scattering, Fourier transform infrared spectroscopy, scanning and transmission electron microscopy, contact angle measurement, ultraviolet–visible spectroscopy, and X-ray powder diffraction revealed that our system has the required physicochemical properties to serve as a novel pH-sensitive drug delivery implant for cancer therapy.