6,380 research outputs found

    The performance of modified jatropha-based nanofluid during turning process

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    The industry's extensive use of petroleum-based metalworking fluid (MWF) harms the environment and humans. The production of bio-based MWF, especially from crude jatropha oil (CJO), has therefore taken numerous initiatives. This aimed to formulate newly modified jatropha oil (MJO) with the addition of 0.05wt.% hBN and 0.05wt.% MoS2 as the nanofluid for MWF. The performance of the nanofluids was determined through the turning process in terms of cutting temperature, workpiece surface roughness, tool life and tool wear of the tool lubricated by the nanofluids. The performance of the nanofluid samples was compared with the synthetic ester (SE). From the results, after conducted 100mm axial cutting length MJO+hBN+MoS2 recorded the lowest in cutting temperature and surface roughness compared to all samples. The result shows that MJO+hBN+MoS2 has longer tool life (6500mm) compared to SE (6000mm). Abrasion and adhesion were observed as the dominant tool wear mechanism. In conclusion, MJO+hBN+MoS2 shows better machining performance and has the potential to be an environmentally friendly metalworking fluid

    Corrosion study of pipeline material for seabed sediment in tropical climate

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    Corrosive environments such as marine sediments can cause corrosion to steel pipelines at any time when certain conditions are met. Seabed sediment could cause severe corrosion damage due to its corrosiveness to the pipelines buried under it. Many consequences could take place in case if there is incident in oil/gas pipelines. Successfully identifying elements of corrosion in marine sediment would enhance the future of steel structure protection and monitoring systems. This article focuses on the behaviour of corrosion rate of steel located near shore environment and the aim is to determine the effect of sediment on corrosion of steel. To investigate that, simulated near shore sediment conditions have been used where the steel coupons buried in sediments which have different characteristics. Weight loss technique has been implemented to determine the weight loss rate of the steel specimens. Based on the results of this study, metal weight loss increases as the duration of exposure to seabed sediment environment become longer. The sea sediment simulated condition has given significant levels of corrosion. Conclusively, the corrosion rate of steel in seabed sediment located in tropical region is complicated and further studies are suggested

    Beaconless Packet Forwarding Approach for Vehicular Urban Environment

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    Existing wireless technologies provide communication and information services to all fields of life. The one of the emerging and popular field is vehicular ad hoc networks, with its unique characteristics and highly mobile environment. Different types of routing protocols have been proposed to address the routing issues in network and one of the most efficient types is geographical routing. In this type of protocols, the beacon messages are using to update the node locations and positions. However, these protoocls have been suffered with high channel congestion issue in the network. To this end, we propose a beaconless packet forwarding strategy based on modified handshake messages mechanism. The protocol uses some realistic metrics to select the next forwarder node such as forward progresss and link quality. The protocol performance is evaluated with existing beacon and beaconless geographical routing protocols. The simulation results showed the better performance of the proposed protocol in terms of packet delay and data delivery ratio in realistic wireless channel conditions

    Objects detection and tracking using fast principle component purist and kalman filter

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    The detection and tracking of moving objects attracted a lot of concern because of the vast computer vision applications. This paper proposes a new algorithm based on several methods for identifying, detecting, and tracking an object in order to develop an effective and efficient system in several applications. This algorithm has three main parts: the first part for background modeling and foreground extraction, the second part for smoothing, filtering and detecting moving objects within the video frame and the last part includes tracking and prediction of detected objects. In this proposed work, a new algorithm to detect moving objects from video data is designed by the Fast Principle Component Purist (FPCP). Then we used an optimal filter that performs well to reduce noise through the median filter. The Fast Region-convolution neural networks (Fast-RCNN) is used to add smoothness to the spatial identification of objects and their areas. Then the detected object is tracked by Kalman Filter. Experimental results show that our algorithm adapts to different situations and outperforms many existing algorithms

    Influence of substrate annealing on inducing Ti3+ and oxygen vacancy in TiO2 thin films deposited via RF magnetron sputtering

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    Nano-crystalline TiO2 has been prepared by RF magnetron sputtering at varied substrate temperatures ranging from 200 to 500 °C. The alteration of oxygen and titanium atom in TiO2 at uppermost surface is clearly observed on the effect of annealing temperature by Auger Electron Spectroscopy (AES) technique. The measurement of peak to peak value of Ti and O transition line at 400 °C indicates the surface chemical state of O2 in TiO2 thin films defect at surface and Fermi level was analyzed using the X-Ray Photoelectron Spectroscopy (XPS). The Ti 2p observation of pre and post surface treatment shows the concentration of Ti3+ is seven times higher after post sputtered for sample 200 °C. Ti3+ decrease by increasing temperature. The Ti3+-oxygen vacancy which also assigned as Ti2O3 occurred in all sample, yet sample deposited at 400 °C gives nearest binding energy for Ti2O3. This observation also supported by The Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) analysis which shows highest total ion count for positive polarity is O+ for sample at 300 °C and Ti ion dominant is Ti2O3 + for sample at 400 °C. Based on the analyses, it is clearly seen that high defect of Ti3+-oxygen vacancy which is located between surface layer and fermi level state, this defect levels was created at surface layer at low annealing temperature. However, increasing temperature leads to defect creation on bellow surface layer which consider as within fermi level laye

    Differentiation of Lactobacillus-probiotic strains by visual comparison of random amplified polymorphic DNA (RAPD) profiles

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    In the present study, distinctive RAPD fingerprints were generated for 12 Lactobacillus-probiotic strains from 5 Lactobacillus species (L. brevis, L. reuteri, L. gallinarium, L. salivarius and L. panis) after optimization of the RAPD parameters such as MgCl2, Taq polymerase, primer concentration and type of primer. The strains were differentiated under the same PCR protocol but different concentration of primer OPM-05 (50 pmole to differentiate the 5 L. brevis strains and 75 pmole to differentiate 2 strains of L. gallinarium, 3 strains of L. reuteri, a strain of L. panis and L. salivarius). The RAPD fingerprints generated could be differentiated by visual comparison of the profiles, without being analysed by relevant software. This allows specific, rapid, immediate and convenient identification of the Lactobacillus strains

    Regional validation of retracked sea levels from SARAL/Altika over the South China sea and adjacent seas

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    This paper focuses on assessing the quality of sea level anomaly (SLA) data from the new generation of Ka-band SARAL/AltiKa satellite altimetry over the continental shelf of the South China Sea. The region consists of peninsulas, shallow seas, and small islands that produce complicated altimetric waveform patterns. The improved-accuracy of SLAs data from the MLE4, Ice1 and Ice2 retrackers which are provided in the AVISO-Sensor Geophysical Data Records (SGDR) were optimized in this study. The quality of retracked SLAs is assessed by making comparison with tide gauge data from six stations. In general, the percentage of data availability of Ice-1 retracker is superior ( > 68%) to those of MLE- 4 and Ice-2 retrackers. The improvement of percentage (IMP) also shows that Ice-1 retracker improves the standard deviation > 12% better than those of Ice-2 retracker. Over complex areas of Lubang and Ko Taphao Noi, the temporal correlation of Ice-1 retracker is superior (r > 0.80) to those of MLE4 and Ice-2 retrackers (r 5.8) and lower RMS error ( < 34 cm) than those of Ice-1 retracker. It can be concluded that the Ice-1 and Ice-2 retrackers were superior for the coastal region of Maritime Continent

    FSM-F: finite state machine based framework for denial of service and intrusion detection in manet

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    Due to the continuous advancements in wireless communication in terms of quality of communication and affordability of the technology, the application area of Mobile Adhoc Networks (MANETs) significantly growing particularly in military and disaster management. Considering the sensitivity of the application areas, security in terms of detection of Denial of Service (DoS) and intrusion has become prime concern in research and development in the area. The security systems suggested in the past has state recognition problem where the system is not able to accurately identify the actual state of the network nodes due to the absence of clear definition of states of the nodes. In this context, this paper proposes a framework based on Finite State Machine (FSM) for denial of service and intrusion detection in MANETs. In particular, an Interruption Detection system for Adhoc On-demand Distance Vector (ID-AODV) protocol is presented based on finite state machine. The packet dropping and sequence number attacks are closely investigated and detection systems for both types of attacks are designed. The major functional modules of ID-AODV includes network monitoring system, finite state machine and attack detection model. Simulations are carried out in network simulator NS-2 to evaluate the performance of the proposed framework. A comparative evaluation of the performance is also performed with the state-of-theart techniques: RIDAN and AODV. The performance evaluations attest the benefits of proposed framework in terms of providing better security for denial of service and intrusion detection attacks

    F3TM: flooding factor based trust management framework for secure data transmission in MANETs

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    Due to the absence of infrastructure support, secure data dissemination is a challenging task in scalable mobile ad hoc networks (MANETs) environment. In most of the traditional routing techniques for MANETs, either security has not been taken into account or only one aspect of security concern has been addressed without optimizing the routing performance. This paper proposes Flooding Factor based Framework for Trust Management (F3TM) in MANETs. True flooding approach is utilized to identify attacker nodes based on the calculation of trust value. Route Discovery Algorithm is developed to discover an efficient and secure path for data forwarding using Experimental Grey Wolf algorithm for validating network nodes. Enhanced Multi-Swarm Optimization is used to optimize the identified delivery path. Simulations are carried out in ns2 to assess and compare the performance of F3TM with the state-of-the-art frameworks: CORMAN and PRIME considering the metrics including delay, packet delivery ration, overhead and throughput. The performance assessment attests the reliable security of F3TM compared to the state-of-the-art frameworks

    Development of a nanobiodegradable drilling fluid using prosopis farcta plant and pomegranate peel powders with metal oxide nanoparticles

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    One of the inevitable problems encountered during the petroleum well drilling process is lost circulation in which part of the drilling fluid is lost into the formation. A combination of nanoparticles with their unique properties and cost-effective biodegradable materials can play an effective role in treating fluid loss. In this study, our aim was to formulate drilling fluids modified with nanoparticles, pomegranate peel powder, and Prosopis farcta plant powder. The drilling fluids were identified and recognized using scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy techniques. Furthermore, experimental tests were conducted in order to investigate the performance of the newly formulated drilling fluid in improving fluid loss characteristics. The obtaining results have shown that adding 0.3 wt % of pomegranate peel powder to the reference (base) drilling fluid reduces the filter loss volume to 7.9 mL compared to the reference fluid (11.6 mL). As the optimal concentration of TiO2 was mixed with 0.3 wt % of pomegranate peel powder then added to the reference fluid, the filter loss volume was reduced to 8.6 mL
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