Combined influence of throughflow and Soret effect on the onset of Marangoni convection

The onset of Marangoni convection with throughflow and the Soret effect in a top-free and bottom-rigid horizontal fluid layer is studied using the normal mode method for different types of thermal and solutal boundary combinations. The bottom surface is either conducting or insulating to temperature and solute concentration perturbations. The resulting eigenvalue problem is solved exactly by assuming that stationary convection is exhibited at the neutral state. It is found that the destabilizing behavior of a small amount of throughflow described by Nield (J Fluid Mech 185:353–360, 1987) becomes more significant in the presence of Soret effect for some boundary combinations. The results are consistent with the existing results in the literature.     

Effect of salt concentration on poly (vinyl chloride)/poly (acrylonitrile) based hybrid polymer electrolytes

Hybrid, solid polymer electrolyte films consisting of poly (vinyl chloride) (PVC), poly (acrylonitrile) (PAN) and, propylene carbonate (PC) with different concentrations of LiClO₄ are prepared by means of a using solvent-casting technique. The structure and complex formation are studied by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The temperature dependence of the ionic conductivities of the polymer films is explained in terms of a free volume model. The conductivities of PVC–PAN–LiClO₄–PC complexes are determined at different salt concentrations. The highest ionic conductivity (8.35 × 10⁻⁵ S cm⁻¹) is obtained for 8 wt.% LiClO₄ in the polymer complex at 304 K. The thermal stability of the electrolyte is examined by thermogravimetric/differential thermal analysis (TG/DTA).     

Cue-based networking

In this paper we present a new approach called cue-based networking that uses hints or cues about the physical environment to optimize networked application behavior. We define the notion of cues and describe how cues can be obtained using wireless sensor networks as the underlying platform. We identify both the research and system challenges that need to be addressed to realize benefits of the approach under a target application of video delivery over IP networks. In the process, we identify key challenges of wireless sensor networks, namely timeliness and robustness. We design an adaptive algorithm that balances the tradeoff between them satisfying both timeliness and robustness requirements. Through an implementation of the video delivery application using the proposed algorithm in a real home environment, we highlight the practical benefits of the proposed approach.     

Flow-through microvial facilitating interface of capillary isoelectric focusing and electrospray ionization mass spectrometry

A capillary electrophoresis mass spectrometry (CE-MS) interface utilizing a flow-through microvial is used to ensure the electric continuity and supply the catholyte and mobilizer solutions during the capillary isoelectric focusing (cIEF) and mobilization process. The flow-through microvial provides a stable chemical environment and helps to improve the ionization efficiency without significantly diluting the analyte. The CE-MS interface facilitates the transfer of the mobilized cIEF effluent to the site of electrospray ionization, and the gaseous ions can be detected directly by a mass spectrometer. It also allows for complete focusing and mobilization processes to be performed automatically in programmed sequences with commercial CE systems. Two different strategies, using either a part of the capillary or the flow-through microvial of the CE-MS interface as the catholyte reservoir for bare fused silica capillaries or neutral coated capillaries, respectively, were developed for automated cIEF-electrospray ionization (ESI)-MS. Reasonable separation efficiency was achieved using proper concentration of carrier ampholytes and suitable strategies of electroosmotic/electrophoretic mobilization.     

Close-range blast loading on empty recyclable metal beverage cans for use in sacrificial cladding structure

This article deals with the experimental and numerical blast study on a single empty recyclable metal beverage can. The idea is to make a macro-foam (sacrificial cladding structure) out of these cans to protect the main load bearing members of civil engineering structures from the air blast load. Close-range free air blast tests have been conducted to understand the crushing behaviour and the energy absorption of a single empty beverage can in detail. To conduct such an air blast test a special small-scale test set-up was designed and manufactured. The effect of skin plate surface area and its nature on the blast parameters is studied. Furthermore, the effect of inertia of the skin plate on the crushing performance of the beverage can is evaluated. Tests have been conducted with different plates (made of aluminium and sandwich composite materials) with different masses which represent the skin plate of the proposed sacrificial structure. The measured blast parameters from the experimental tests were compared with ConWep predicted data. Furthermore, the influence of the finite surface area of the skin plate on the clearing of the reflected pressure waves was also studied. The deformation behaviour and the corresponding energy absorption of empty beverage cans were captured. During the experimental blast tests it was observed that a part of the total reflected impulse (∼30%) was lost before it transfers to the non-sacrificial structure. Hence, in order to investigate this phenomenon Eulerian-Lagrangian coupled analyses were conducted using Hydrocodes. The results from these analyses showed that the diffraction and ground reflected pressure wave caused the loss in impulse. The results from the numerical studies have been compared and validated with the experimental results.     

Enabling Energy Efficient Sensory Data Collection Using Multiple Mobile Sink

Mobile sink is the challenging task for wireless sensor networks （WSNs）. In this paper we propose to design an efficient routing protocol for single mobile sink and multiple mobile sink for data gathering in WSN. In this process, a biased random walk method is used to determine the next position of the sink. Then, a rendezvous point selection with splitting tree technique is used to find the optimal data transmission path. If the sink moves within the range of the rendezvous point, it receives the gathered data and if moved out, it selects a relay node from its neighbours to relay packets from rendezvous point to the sink. Proposed algorithm reduces the signal overhead and improves the triangular routing problem. Here the sink acts as a vehicle and collect the data from the sensor. The results show that the proposed model effectively supports sink mobility with low overhead and delay when compared with Intelligent Agent-based Routing protocol （IAR） and also increases the reliability and delivery ratio when the number of sources increases.     

A combined r-h adaptive strategy based on material forces and error assessment for plane problems and bimaterial interfaces

An r-h adaptive scheme has been proposed and formulated for analysis of bimaterial interface problems using adaptive finite element method. It involves a combination of the configurational force based r-adaption with weighted laplacian smoothing and mesh enrichment by h-refinement. The Configurational driving force is evaluated by considering the weak form of the material force balance for bimaterial inerface problems. These forces assembled at nodes act as an indicator for r-adaption. A weighted laplacian smoothing is performed for smoothing the mesh. The h-adaptive strategy is based on a modifed weighted energy norm of error evaluated using supercovergent estimators. The proposed method applies specific non sliding interface strain compatibility requirements across inter material boundaries consistent with physical principles to obtain modified error estimators. The best sequence of combining r- and h-adaption has been evolved from numerical study. The study confirms that the proposed combined r-h adaption is more efficient than a purely h-adaptive approach and more flexible than a purely r-adaptive approach with better convergence characteristics and helps in obtaining optimal finite element meshes for a specified accuracy.     

Multiobjective optimization and analysis of copper–titanium diboride electrode in EDM of monel 400™ alloy

Electrical discharge machining (EDM) is one of the most accepted machining processes in the precision manufacturing industry. In EDM process, finding an alternative tool material is the demand in modern manufacturing industry. Therefore, an attempt had been made to fabricate copper–titanium diboride powder metallurgy electrode to test in EDM on monel 400? material. The experiments are planned using center composite second-order rotatable design and the model is developed by response surface methodology. The machining characteristics have analyzed using the developed model. In this study, four input parameters such as titanium diboride percentage, pulse current, pulse on time, and flushing pressure are selected to evaluate the material removal rate (MRR) and tool wear rate (TWR). The adequacy of the developed regression model has tested through analysis of variance test. The desirability-based multiobjective optimization is used to find the optimal process parameter which has given maximum MRR and minimum TWR. The optimum process parameters obtained were titanium diboride of 16%, pulse current of 6 A, flushing pressure of 1 Mpa, and pulse on time of 35?µs. The validity of the response surface model is further verified by conducting confirmation experiments.     

Drying and energy aspects of tapioca sago processing-an experimental field study

Journal of Mechanical Science and Technology - The drying characteristics of tapioca sago were studied using four different drying methods—Open sun drying (OSD), Conveyor belt drying (CBD),...