Experimental study on the effects of bearing wall thickness and bearing length on the frictional characteristics of sintered bearings

Experiments were conducted on bronze sintered bearings to determine the effect of bearing wall thickness and bearing length on the coefficient of friction. Parameters such as the radial clearance, the surface roughness of the shaft and the lubricating oil were kept constant in all the test bearings during the experiments. It was found that the coefficient of friction increases with the wall thickness and decreases with an increase in bearing length. It is felt that the above result will be useful for the users of sintered bearings in making a judicious selection of the wall thickness and the length of the bearing such that the selection results in a larger bearing metal volume to store more lubricating oil giving a longer life and a reduced coefficient of friction.     

A cluster prediction model-based data collection for energy efficient wireless sensor network

The Journal of Supercomputing - Wireless sensor networks (WSN) are expected to cover the major portion of the earth’s surface in the coming years. In the era of IoT, the WSN is the major data...     

Solution-processed,flexible and broadband photodetector based on CsPbBr_3/PbSe quantum dot heterostructures

Due to their promising applications in foldable displays,optical communication equipment and environmental monitoring systems,flexible and broadband optoelectronic devices have gained extensive attention in recent years.Here,a flexible and broadband photodetector based on CsPbBr₃/PbSe quantum dot(QD) heterostructures is firstly presented.The integrated QD heterostructures possess consecutive detection range from ultraviolet(UV) to long-wave length infrared(LW-IR) regions with efficient light absorption and chemical stability,in comparison with the pristine PbSe QDs.Systematic material characterizations reveal the improved exciton dissociation,carrier transport and carrier lifetime of the QD heterostructures.Flexible photodetector Ag/CsPbBr₃/PbSe/Ag demonstrate a high responsivity of 7.17 A/W with a specific detectivity of 8.97 × 10¹² Jones under 25 μW/cm² 365 nm illumination at 5 V.Furthermore,it could maintain 91.2 %(or 94.9 %) of its initial performance even after bending for thousands of times(or exposing in ambient air for 4 weeks).More importantly,its re s ponse time is shortened more than three orders of magnitude as that of pristine PbSe QDs-based photodetectors.Therefore,it provides a feasible and promising method for the next-generation high-performance broadband photodetectors via constructing heterostructures of various QDs.     

Energy efficient secured K means based unequal fuzzy clustering algorithm for efficient reprogramming in wireless sensor networks

Wireless Networks - Wireless Sensor Networks (WSNs) is a collection of tiny distributed sensor nodes that have been used to sense the physical parameters of the environment where it has been...     

A Green Metal–Organic Framework-Cyclodextrin MOF: A Novel Multifunctional Material Based Triboelectric Nanogenerator for Highly Efficient Mechanical Energy Harvesting

The naturally available cyclodextrin has opened up a wide range of research avenues because of its superior characteristics such as being non-toxic, biocompatible, and edible. The cyclodextrin is the green multifunctional material that can add to the triboelectric series and extend its self-powered applications. The ultrasonic synthesized cyclodextrin metal–organic framework (CD-MOF) designed using sodium as a metal ion and cyclodextrin as a ligand for the triboelectric nanogenerator is reported. The various detailed characterizations of the CD-MOFs give an insight into the properties of the synthesized material. The Kelvin probe force microscopy suggests three types of CD-MOFs, exhibiting a positive potential. As per the surface potential, the output of the various CD-MOF based TENG is varied as alpha CD MOF/Teflon > gamma CD-MOF/Teflon > beta CD-MOF/Teflon. The alpha CD MOF/Teflon TENG produces an electrical output of 152 V, 1.2 μA, and 14.3 nC, respectively. The fabricated device output is utilized for powering numerous low-power electronics through a capacitor and bridge rectifier circuit. The multiunit Z-shaped TENG device is attached to various surfaces such as the shoe heel and the backside of the school bag, and the corresponding energy harvesting response is demonstrated.     

A CFD study of low pressure wet gas metering using slotted orifice meters

Wet gas metering is becoming an increasingly important problem to many industries, in particular the oil and gas industry. Extensive studies have been done in the past on Venturi and standard orifice differential pressure (DP) flow meters to tackle wet gas flow problems. However in recent years, the slotted orifice flow meter has been developed in the attempt to improve the performance of the standard orifice meter. The novel flow meter is shown to be insensitive to the upstream flow profile with lower head loss and faster pressure recovery. This paper describes the numerical studies to establish the effect of different geometrical perforations on the performance of the slotted orifice. Three sets of slotted orifices with varying aspect ratios (1.5≤l/w≤3.0), of rectangular perforations and one slotted orifice with a circular perforation and a β ratio of 0.40 are simulated in a 1.6 m horizontal pipe using the k-ε turbulence model over a range of parameters, i.e. gas volume fraction (GVF) and gas mass flow rate. The commercial CFD code, FLUENT 6.3 was used to model the wet gas flow. Simulation results revealed that the shape of the perforation has no effect on the differential pressure, However, a marginally better pressure recovery was observed with rectangular perforations of l/w=3.0. The relatively higher over-reading values obtained in this work are consistent with the results of Geng et al. (2006) [1] that for a slotted orifice, a low β ratio is more sensitive to the liquid presence in the stream and hence is preferable for wet gas metering. Mass flow prediction by wet gas correlations showed that the homogeneous model, Steven’s and De Leeuw’s correlations had the best performance, with a calculated mean error of 4%-5%.     

Investigating a new approach to film casting for enhanced drug content uniformity in polymeric films

Films prepared by conventional casting onto trays such as teflon-coated perspex trays (TCPTs) suffer from poor drug content uniformity. The aim of this study was to prepare a silicone-molded tray (SMT) with individual wells for film casting and to evaluate it in terms of enhancing drug content uniformity. Films were prepared by solvent evaporation or emulsification and cast onto TCPT and SMT. Preparation of films by the SMT method was superior in terms of meeting drug content uniformity requirements. As compared with the TCPT method, the SMT casting method also reduced the variability in mucoadhesivity, drug release, and film thickness. Reproducibility of the SMT method was demonstrated in terms of drug content, mucoadhesion, and drug release.     

Ultra‐Thin Layered Ternary Single Crystals [Sn(SxSe1−x)2] with Bandgap Engineering for High Performance Phototransistors on Versatile Substrates

2D ternary semiconductor single crystals, an emerging class of new materials, have attracted significant interest recently owing to their great potential for academic interest and practical application. In addition to other types of metal dichalcogenides, 2D tin dichalcogenides are also important layered compounds with similar capabilities. Yet, multi‐elemental single crystals enable to assist multiple degrees of freedom for dominant physical properties via ratio alteration. This study reports the growth of single crystals Se‐doped SnS₂ or SnSSe alloys, and demonstrates their capability for the fabrication of phototransistors with high performance. Based on exfoliation from bulk high quality single crystals, this study establishes the characteristics of few‐layered SnSSe in structural, optical, and electrical properties. Moreover, few‐layered SnSSe phototransistors are fabricated on both rigid (SiO₂/Si) and versatile polyethylene terephthalate substrates and their optoelectronic properties are examined. SnSSe as a phototransistor is demonstrated to exhibit a high photoresponsivity of about 6000 A W^?1 with ultra‐high photogain ≈8.8 × 10⁵, fast response time ≈9 ms, and specific detectivity (D*) ≈8.2 × 10¹² J. These unique features are much higher than those of recently published phototransistors configured with other few‐layered 2D single crystals, making ultrathin SnSSe a highly qualified candidate for next‐generation optoelectronic applications.     

The journal Communications in Numerical Methods in Engineering with Biomedical Applications becomes the International Journal for Numerical Methods in Biomedical Engineering (IJNMBE) from 1st January 2010

Communications in Numerical Methods in Engineering, founded by Roland W. Lewis in 1985, will change its title to the ‘International Journal for Numerical Methods in Biomedical Engineering’ and have a revised Aims and Scope. Copyright © 2009 John Wiley & Sons, Ltd.     

Combined Effect of Mixed Convection and Surface Radiation Heat Transfer for Thermally Developing Flow in Vertical Channels

Combined effect of laminar flow mixed convection and surface radiation heat transfer for thermally developing airflow in a vertical channel heated from a side has been experimentally examined with different thermal and geometric parameters. The channel boundary is made of two isothermal walls and two adiabatic walls, the isothermal parallel wall is heated uniformly and the opposite cold wall temperature is maintained equal to the inlet conditions. The heated wall temperature ranged from 55 to 100°C, Reynolds number ranged from 800 to 2900 and the heat flux was varied from 250 to 870 W/m². To cover the wide range of Reynolds numbers, two aspect ratios of square and rectangular section were used. Surface radiation from the internal walls is considered through two emissivities i.e. 0.05 and 0.85, to represent weak and strong radiation effects, respectively. From the experiments, surface temperature and Nusselt number distributions of convection and radiation heat transfer are obtained for different heat flux values. Flow structure inside the channel is visualized to observe the flow pattern. The results show the combined effect of laminar flow mixed convection and surface radiation on the total heat transfer rate within the channel. The accumulating buoyancy force and airflow moves together vertically in the upward direction to give significant heat transfer enhancement in the vertical orientation of the channel.