Effect of homogenisation conditions on recrystallisation in the Al-Mg-Mn alloy AA5454

The purpose of the present work is to understand the microstructure development and, particularly, to control the progress of recrystallisation in hot strip in the Al-Mg-Mn alloy AA 5454, which is typically used for the manufacture of structural automotive components. The chemical composition, together with the thermomechanical processing history of this material, has a strong influence on the microstructure of the product and the resulting properties as it is supplied to the customer. Electrical conductivity measurements, thermal analysis and electron microscopy have been carried out to characterise the evolution of precipitation state at various stages in the processing route. The conditions of the homogenisation heat treatment have been varied, and the effect on subsequent recrystallisation after hot rolling has been evaluated in both the as cast and rough rolled condition by optical microscopy techniques. Results indicate that the conditions of homogenisation heat treatment and roughing rolling are critical for the generation of a suitable recrystallised microstructure in AA 5454 hot strip. A new two stage homogenisation practice has been developed to expedite post-rolling recrystallisation in this alloy

An Electronically Reconfigurable Patch Antenna Design for Polarization Diversity with Fixed Resonant Frequency

In this paper, an electronically polarization reconfigurable circular patch antenna with fixed resonant frequency operating at Wireless Local Area Network (WLAN) frequency band (2.4-2.48 GHz) is presented. The structure of the proposed design consists of a circular patch as a radiating element fed by coaxial probe, cooperated with four equal-length slits etched on the edge along x-axis and y-axis. A total of four switches was used and embedded across the slits at specific locations, thus controlled the length of the slits. By activating and deactivating the switches (ON and OFF) across the slits, the current on the patch is changed, thus modifying the electric field and polarization of the antenna. Consequently, the polarization excited by the proposed antenna can be switched into three types, either linear polarization, left-hand circular polarization or right-hand circular polarization. This paper proposes a simple approach that able to switch the polarizations and excited at the same operating frequency. Simulated and measured results of ideal case (using copper strip switches) and real case (using PIN diode switches) are compared and presented to demonstrate the performance of the antenna

Hemodynamic prediction in patent ductus arteriosus morphologies

Patent ductus arteriosus (PDA) is a condition in which the ductus arteriosus remain opened after birth, causing the blood to shunt through from the aorta to the pulmonary artery. However, due to the complicated nature of the arterial geometry, the flow characteristic inside the PDA is not fully understood, since simplified model are commonly used in researches. This study aims to identify the hemodynamic characteristic in three different patient-specific morphologies. Computational modeling via computational fluid dynamic (CFD) is implemented to predict the blood flow behavior in different PDA morphologies. The result shows that low wall shear stress is observed at the region where the flow recirculation occurs. High wall shear stress is observed in the pulmonary artery due to increase of flow velocity at the insertion point of PDA. The PDA morphologies exhibit left-to-right shunt, which diverts approximately 10% of blood flow from the aorta to the pulmonary artery. The highest shunted blood flow is found in TR LPA morphology. High value of OSI indicates the changes of wall shear stress vector. It is observed that DS LPA has the highest area covered by OSI which presents better hemodynamic characteristic as compared to other morphology

3D Object Recognition Using Multiple Views And Neural Networks.

This paper proposes a method for recognition and classification of 3D objects. The method is based on 2D moments and neural networks. The 2D moments are calculated based on 2D intensity images taken from multiple cameras that have been arranged using multiple views technique. 2D moments are commonly used for 2D pattern recognition

Comparative study ofthe computational fluid dynamics and fluid structure interaction analysis in human airways flow

Numerous studies have been done in order to get the most accurate result that represents the flow characteristics inside the human trachea. Numerical method was the most favorite type of study chosen to simulate the model due to the complexity of the geometry and difficulties to get the real trachea to do the experimental works. In this study, one actual healthy model of human trachea was reconstructed in order to compare, the different of the velocity and pressure distribution between two types of numerical modeling analysis: Computational Fluid Dynamics (CFD) and Fluid Structure Interaction (FSI) analysis. The model was extracted using the Computed Tomography (CT) scan images to maintain the realistic geometry. Velocity, 1.24 m/s was used at the inlet and the variations of the velocity and pressure distribution along the trachea were observed. The results shown that, the implementation of the FSI technique did produce different result and flexibility of the structure wall did influence the distribution of the velocity and pressure along the trachea

A Comparative Study of Some Cellular Manufacturing Techniques

Cellular manufacturing (CM) is a concept that involves processing of similar parts on dedicated cluster (or cells) of dissimilar machines or manufacturing processes. This paper concentrated on seven cell formation techniques used in Cellular Manufacturing (CM). The techniques were used to develop cells for matrices from various sizes of parts and machines. By randomly rearranging the sequence of the machines in the reference matrices (cited from published journals), 12 new matrices were developed. This paper also concentrated on performing the treatments for bottleneck, exceptional elements or voids using part subcontracting or machine duplication for the developed cells. The performance of each technique was measured using Grouping Measures (GM), where high percentage of GM indicates that the technique has high machine utilization (MU) and low percentage of exceptional elements (EE). Overall, Bond Energy Algorithm (BEA) was found to be the best cell formation technique

Storyline description of Southern Hemisphere midlatitude circulation and precipitation response to greenhouse gas forcing

As evidence of climate change strengthens, knowledge of its regional implications becomes an urgent need for decision making. Current understanding of regional precipitation changes is substantially limited by our understanding of the atmospheric circulation response to climate change, which to a high degree remains uncertain. This uncertainty is reflected in the wide spread in atmospheric circulation changes projected in multimodel ensembles, which cannot be directly interpreted in a probabilistic sense. The uncertainty can instead be represented by studying a discrete set of physically plausible storylines of atmospheric circulation changes. By mining CMIP5 model output, here we take this broader perspective and develop storylines for Southern Hemisphere (SH) midlatitude circulation changes, conditioned on the degree of global-mean warming, based on the climate responses of two remote drivers: the enhanced warming of the tropical upper troposphere and the strengthening of the stratospheric polar vortex. For the three continental domains in the SH, we analyse the precipitation changes under each storyline. To allow comparison with previous studies, we also link both circulation and precipitation changes with those of the Southern Annular Mode. Our results show that the response to tropical warming leads to a strengthening of the midlatitude westerly winds, whilst the response to a delayed breakdown (for DJF) or strengthening (for JJA) of the stratospheric vortex leads to a poleward shift of the westerly winds and the storm tracks. However, the circulation response is not zonally symmetric and the regional precipitation storylines for South America, South Africa, South Australia and New Zealand exhibit quite specific dependencies on the two remote drivers, which are not well represented by changes in the Southern Annular Mode

PREPARATION AND EVALUATION OF ANTHRALIN BIODEGRADABLE NANOPARTICLES AS A POTENTIAL DELIVERY SYSTEM FOR THE TREATMENT OF PSORIASIS

Objective: Anthralin is one of the most effective drugs in psoriasis management. However, its side effects and unfavourable physicochemical properties limit its clinical use. Therefore, the objective of this study was to prepare and evaluate poly (ethylene glycol)-block-poly (ε-caprolactone) (PEG-b-PCL) nanoparticles as a potential delivery system for anthralin.Methods: PEG-b-PCL nanoparticles were prepared by the co-solvent evaporation method and evaluated using a variety of techniques. The effect of drug/polymer weight feed ratio on the nanoparticle size, drug loading capacity and encapsulation efficiency were studied. Drug release kinetics were studied using the dialysis bag method. Nanoparticle size was measured using dynamic light scattering and confirmed by transmission electron microscopy measurements.Results: PEG-b-PCL formed spherical nanoparticles having a diameter of 40 to 80 nm based on the polymer and level of drug loading. The size observed by TEM measurements was slightly smaller than that obtained by DLS due nanoparticle dryness during measurement. Drug loading capacity increased with increasing the drug/polymer ratio and a maximum loading of ~25% was obtained. Anthralin encapsulation in the nano particles resulted in ~120-fold increase in its aqueous solubility. Anthralin was released from the nanoparticles over a prolonged period of time where ~ 45% was released in 48 h.Conclusion: These results confirm the utility of PEG-b-PCL nanoparticles in enhancing the aqueous solubility and sustaining the release of athralin. Therefore, they might be used as a potential delivery system for the treatment of psoriasis.Â

Measurements of Radar Backscatter from an Artificial Tree an Indication of Azimuthal Variations and Polarisation Sensitivity of Trees

Measurements of radar backscatter from an artificial tree were made in the laboratory at 6 and 10 GHz at horizontal incidence. The system has resolution cylinder 18 cm in diameter and 11 cm long. The tree itself was only 30.5 cm high so about half the tree was within the beam. The scattering was azimuthally uniform. Tilted polarizations gave results favoring an angle corresponding with that of the branches. Measurements were made with and without leaves