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Establishing empirical relationships to predict grain size and tensile strength of friction stir welded AA 6061-T6 aluminium alloy joints 被引量:18
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作者 S.rajakumar C.MURALIDHA RAN V.BALASUBRAMANIAN 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第10期1863-1872,共10页
AA 6061-T6 aluminium alloy(Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high specific strength and good corrosion resistance.Compared with the fusion welding p... AA 6061-T6 aluminium alloy(Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high specific strength and good corrosion resistance.Compared with the fusion welding processes that are routinely used for joining structural aluminium alloys,friction stir welding(FSW) process is an emerging solid state joining process in which the material welded does not melt and recast.Joint strength is influenced by the grain size and tensile strength of the weld nugget region.Hence,an attempt was made to develop empirical relationships to predict grain size and tensile strength of friction stir welded AA 6061-T6 aluminium alloy joints.The empirical relationships are developed by response surface methodology(RSM) incorporating FSW tool and process parameters.A linear regression relationship was also established between grain size and tensile strength of the weld nugget of FSW joints. 展开更多
关键词 AA 6061-T6 alloy friction stir welding analysis of variance regression analysis grain size tensile strength
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Histopathological studies and oxidative stress of synthesized silver nanoparticles in Mozambique tilapia (Oreochromis mossambicus) 被引量:14
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作者 rajakumar Govindasamy Abdul Abdul Rahuman 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2012年第6期1091-1098,共8页
To evaluate the potential environmental effects of engineered nano metals,it is important to determine the adverse effects of various nanomaterials on aquatic species.Adult tilapia (Oreochromis mossambicus) were mai... To evaluate the potential environmental effects of engineered nano metals,it is important to determine the adverse effects of various nanomaterials on aquatic species.Adult tilapia (Oreochromis mossambicus) were maintained in 10 L glass aquaria,and exposed to a graded series of synthesized silver nanoparticles (Ag-NPs) at 25,50 and 75 mg/L for eight days.The LC 50 value was 12.6 mg/L.Reduced activities of antioxidant enzymes and the contents of antioxidants were lowered in the gills and liver of fishes treated with AgNPs,which resulted in heavy accumulation of free radicals.Histopathological results imply that the balance between the oxidative and antioxidant system in the fish was broken down during Ag-NPs exposure.The principal concern related with the release of nanomaterials and their smaller particle may change the materials transport and potential toxicity to aquatic organisms compared to larger particles. 展开更多
关键词 silver nanoparticles Oreochromis mossambicus oxidative stress analysis histopathological studies toxic effect
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A review on the parasitic isopod genus Notophryxus G.O.Sars,1883(Crustacea:Isopoda),and first report of Notophryxus globularis G.O.Sars,1885 from Lakshadweep Sea(Amini Island)
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作者 Mukkattu Nazar Suhaana Jaime Gómez-Gutiérrez +2 位作者 Paravanparambil rajakumar Jayachandran Punnakkal Hari Praved Sivasankaran Bijoy Nandan 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第8期142-153,共12页
Isopod crustaceans of the family Dajidae are exclusively marine ectoparasites.The genus Notophryxus G.O.Sars,1883 currently includes nine nominal species,which are very rarely reported as the chances for encountering ... Isopod crustaceans of the family Dajidae are exclusively marine ectoparasites.The genus Notophryxus G.O.Sars,1883 currently includes nine nominal species,which are very rarely reported as the chances for encountering these specimens are unpredictable.Our comprehension of the taxonomy,biology,ecology,and life cycle of species belonging to the Notophryxus genus is notably lacking.All nominal species of Notophryxus genus are reviewed here to obtain a comprehensive and integrative taxonomic understanding of this genus,in an attempt to address the lacunae.This paper also documents the rediscovery of an ectoparasitic isopod from the genus Notophryxus in Indian waters,after 55 years.Adult isopod specimens obtained from the outer reefs of Amini Island in the Lakshadweep archipelago,Southeastern Arabian Sea,display morphological congruence to Notophryxus globularis G.O.Sars,1885.The only previous report on this species dates back to 1885 from G.O.Sars'description of N.globularis as an ectoparasite on the euphausiid Thysanoessa gregaria G.O.Sars,1883 in the North Pacific.This discovery represents a range extension of N.globularis from the North Pacific to the Arabian Sea.Two cryptoniscid larvae and three adult females of N.globularis(with dwarf males)were found attached to four adult mysid specimens of Siriella aequiremis Hansen,1910.The present study provides an improved diagnosis of N.globularis with the aid of light microscopy images and line drawings which was not given in the original G.O.Sars,1885 report.This research also provides a concise description of cryptoniscid larvae from the same sampling location and same host which is most likely to be N.globularis larvae. 展开更多
关键词 Dajiidae MYSID cryptoniscan larvae Southeastern Arabian Sea Notophryxus
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Green synthesis of titanium dioxide nanoparticles using Psidium guajava extract and its antibacterial and antioxidant properties 被引量:4
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作者 Thirunavukkarasu Santhoshkumar Abdul Abdul Rahuman +7 位作者 Chidambaram Jayaseelan Govindasamy rajakumar Sampath Marimuthu Arivarasan Vishnu Kirthi Kanayairam Velayutham John Thomas Jayachandran Venkatesan Se-Kwon Kim 《Asian Pacific Journal of Tropical Medicine》 SCIE CAS 2014年第12期968-976,共9页
Objective:To determine the efficacies of antibacterial and antioxidant activities of aqueous leaf extract of Psidium guajava mediated biosynthesis of titanium dioxide nanoparticles(TiO_2,NPs).Methods:Synthesized TiO_2... Objective:To determine the efficacies of antibacterial and antioxidant activities of aqueous leaf extract of Psidium guajava mediated biosynthesis of titanium dioxide nanoparticles(TiO_2,NPs).Methods:Synthesized TiO_2 NPs were tested by disc diffusion method against against human pathogenic bacteria.The total antioxidant activity and phenolic content(Folin—Ciocalteau method) of synthesized TiO_2 NTs and aqueous plant extract were determined.The scavenging radicals were estimated hv DPPH method.The synthesized TiO_2 NPs were characterized by XRD,FTIR.FESEM and EDX,Results:FTIR spectra of synthesized TiO_2 NPs exhibited prominent peaks at 3410 cm^(-1)(alkynes),1 578 cm^(-1).1 451 cm^(-1)(alkanes),and 1 123 cm^(-1)(C-O absorption).The morphological characterization of synthesized TiO_2 NPs was analysed by FESEM which showed spherical shape and clusters with an average size of 32.58 nm.The maximum zone of inhibition was observed in the synthesized TiO_2 NPs(20 μg/mL) against Staphylococcus aureus(25 mm) and Escherichia coli(23 mm).The synthesized TiO_2 NPs showed more antibacterial activity than the standard antibiotic disk,tetracycline which drastically reduces the chances for the development of antibiotics resistance of bacterial species.The plant aqueous extract and synthesized TiO_2NPs were found to possess maximum antioxidant activity when compared with ascorbic acid.The content of phenolic compounds(mg/g) in Leaf aqueous extract and synthesized TiO_2 NPs were found to be 85.4 and 18.3 mgTA/g,respectively.Conclusions:Green synthesized TiO_2 NPs provides a promising approach can satisfy the requirement of large-scale industrial production hearing the advantage of low—cost,eco—friendly and reproducible. 展开更多
关键词 TiO_2 nanoparticles Psidium guajava FTIR Electron microscopy Antibacterial activity Antioxidant activity
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Unlocking the diagnostic potential of vascular endothelial growth factor and interleukin-17: Advancing early detection strategies for hepatocellular carcinoma
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作者 Shanmathi Subramanian Hamrish Kumar rajakumar 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第11期3639-3642,共4页
Tian et al investigated the diagnostic value of serum vascular endothelial growth factor(VEGF)and interleukin-17(IL-17)in primary hepatocellular carcinoma(PHC).Their retrospective study,published in the World Journal ... Tian et al investigated the diagnostic value of serum vascular endothelial growth factor(VEGF)and interleukin-17(IL-17)in primary hepatocellular carcinoma(PHC).Their retrospective study,published in the World Journal of Gastrointestinal Surgery,revealed that the serum levels of VEGF and IL-17 are significantly elevated in PHC patients compared with healthy controls.These biomarkers are closely associated with pathological features such as tumor metastasis and clinical tumor node metastasis stage.A receiver operating characteristic analysis further confirmed the diagnostic efficacy thereof,suggesting that VEGF and IL-17 could serve as valuable tools for early detection and treatment guidance.This study underscores the potential of integrating these biomarkers into clinical practice to increase diagnostic accuracy and improve patient management in PHC. 展开更多
关键词 Hepatocellular carcinoma Biomarkers Early detection Diagnostic accuracy Treatment strategies Therapeutic targets
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2002~2005年期间萨斯喀彻温省儿科三级医疗中心因呼吸道合胞病毒感染住院的儿童病例分析(英文) 被引量:3
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作者 Ayisha Kurji Ben Tan +6 位作者 Jaya Bodani Bonnie Janzen Athena McConnell Rachana Bodani Derek rajakumar Anil Sharma Koravangattu Sankaran 《中国当代儿科杂志》 CAS CSCD 北大核心 2014年第10期1005-1013,共9页
中文概呼吸道合胞病毒(RSV)是2岁以下儿童呼吸道感染最常见的病原体,也是引起婴儿病毒感染所致死亡的主要原因。到目前为止,尚未见加拿大萨斯喀彻温省RSV流行病学的研究报道。本研究的目的是描述2002年7月至2005年6月期间在萨斯喀... 中文概呼吸道合胞病毒(RSV)是2岁以下儿童呼吸道感染最常见的病原体,也是引起婴儿病毒感染所致死亡的主要原因。到目前为止,尚未见加拿大萨斯喀彻温省RSV流行病学的研究报道。本研究的目的是描述2002年7月至2005年6月期间在萨斯喀彻温省的两个儿科三级医疗中心,即皇家大学医院(RUH)和萨斯卡通和里贾纳总医院(RGH),因RSV感染住院的儿童的流行病学特点及疾病严重程度,其中部分患儿有帕利珠单抗(palivizumab)预防史。 在上述2个医疗中心住院时间≥24h的儿童(年龄:从出生到16岁11个月)经实验室病毒鉴定确诊为RSV感染的儿童纳入本研究。在RUH中心,患儿鼻咽部分泌物经直接荧光抗体(DFA)检测阳性者确诊为RSV感染。如果DFA为阴性,则对该标本进行病毒培养。在RGH中心,所有患儿鼻咽部分泌物标本均进行DFA检测和病毒培养。确诊后对患儿的健康记录进行回顾性分析,内容包括患儿的人口统计信息、转诊模式、帕利珠单抗预防史、感染严重程度及转归。目前尚无统一的感染严重程度的判断标准,本研究根据住院时间、是否需要小儿重症监护及持续时间、是否机械通气等进行评估。在研究期间,萨斯喀彻温省的帕利珠单抗预防的标准与加拿大儿科学会(CPS)的建议一致。 2002年7月至2005年6月3年期间,总共有590名RSV儿童(包括324名男童)住院治疗,共602次住院记录,其中12名儿童住院1次以上。入院时患儿中位实足年龄为5.3个月,平均住院时间为4.0d(范围:〈1d至121.2个月)。82.4%的患儿出生时胎龄≥36周,7.5%为33-35周,9.5%≤32周。RSV感染住院情况呈现季节性模式,其中大部分发生在三月和六月。患儿最常见的临床表现为细支气管炎(70.2%),38.1%表现为肺炎,17.3%为上呼吸道感染,0.5%表现为哮吼(患儿可能同时� 展开更多
关键词 呼吸道合胞病毒 帕利珠单抗 儿童
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Oxygen sufficiency controls TOP mRNA translation via the TSC-Rheb-mTOR pathway in a 4E-BP-independent manner 被引量:3
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作者 Rachel Miloslavski Elad Cohen +12 位作者 Adam Avraham Yifat I luz Zvi Hayouka Judith Kasir Rajini Mudhasani Stephen N. Jones Nadine Cybulski Markus A. Ruegg Ola Larsson Valentina Gandin Arjuna rajakumar Ivan Topisirovic Oded Meyuhas 《Journal of Molecular Cell Biology》 SCIE CAS CSCD 2014年第3期255-266,共12页
Cells encountering hypoxic stress conserve resources and energy by downregulating the protein synthesis. Here we demonstrate that one mechanism in this response is the translational repression of TOP mRNAs that encode... Cells encountering hypoxic stress conserve resources and energy by downregulating the protein synthesis. Here we demonstrate that one mechanism in this response is the translational repression of TOP mRNAs that encode components of the translational apparatus. This mode of regulation involves TSC and Rheb, as knockout of TSC1 or TSC2 or overexpression of Rheb rescued TOP mRNA translation in oxygen-deprived celts. Stress-induced translational repression of these mRNAs closely correlates with the hypophosphorylated state of 4E-BP, a translational repressor. However, a series of 4E-BP loss- and gain-of-function experiments disprove a cause-and- effect relationship between the phosphorylation status of 4E-BP and the translational repression of TOP mRNAs under oxygen or growth factor deprivation. Furthermore, the repressive effect of anoxia is similar to that attained by the very efficient inhibition of mTOR activity by Torin 1, but much more pronounced than roptor or rictor knockouL Likewise, deficiency of raptor or rictor, even though it mildly downregulated basal translation efficiency of TOP mRNAs, failed to suppress the oxygen-mediated translational activation of TOP mRNAs. Finally, co-knockdown of TIA-1 and TIAR, two RNA-binding proteins previously implicated in translational repression of TOP mRNAs in amino acid-starved cells, failed to relieve TOP mRNA translation under other stress conditions. Thus, the nature of the proximal translational regulator of TOP m RNAs remains elusive. 展开更多
关键词 HYPOXIA roTOR TOP mRNAs translational control 4E-BP
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Study on the Performance Deterioration of Mixed Flow Impeller due to Change in Tip Clearance 被引量:3
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作者 Ramesh rajakumar.D Ramamurthy.S Govardhan.M 《Journal of Thermal Science》 SCIE EI CAS CSCD 2013年第6期532-538,共7页
Performance of mixed flow compressor with un-shrouded impeller strongly depends upon unsteady, asymmetrical flow fields in the axial directions. The flow through the mixed flow impeller is complex due to three-dimensi... Performance of mixed flow compressor with un-shrouded impeller strongly depends upon unsteady, asymmetrical flow fields in the axial directions. The flow through the mixed flow impeller is complex due to three-dimensional nature of geometry. In mixed flow impeller, there are clearances between the rotating impeller blades and the casing as the high pressure ratio compressors are usually open shrouded impellers. As a result, certain amount of reduction in the performance is unavoidable due to clearance flows. In the present investigations, numerical analysis is performed using a commercial code to investigate tip clearance effects on through flow. The performance of mixed flow impeller with four different clearances between impeller and stationary shroud are evaluated and compared with experimental results. The impeller performance map was obtained for different operating speeds and mass flow rates with different tip clearances. The result shows that the tip leakage flow strongly interacts with mainstream and contributes to total pressure loss and performance reduction. The pressure and performance decrement are approximately linearly proportional to the gap between impeller and stationary shroud.The analysis showed scope for improvement in design of the compressor for better performance in terms of efficiency and operating range. 展开更多
关键词 Mixed Flow Compressor SURGE STALL CHOKE CFD Tip Clearance Compressible Flow Periodic Grids and Jet-Wake
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Multi-objective optimization of friction stir welding parameters using desirability approach to join Al/SiC_p metal matrix composites 被引量:3
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作者 P.PERIYASAMY B.MOHAN +2 位作者 V.BALASUBRAMANIAN S.rajakumar S.VENUGOPAL 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第4期942-955,共14页
Silicon carbide particulate (SiCp) reinforced cast aluminium (A1) based metal matrix composites (MMCs) have gained wide acceptance in the fabrication of light weight structures requiring high specific strength, ... Silicon carbide particulate (SiCp) reinforced cast aluminium (A1) based metal matrix composites (MMCs) have gained wide acceptance in the fabrication of light weight structures requiring high specific strength, high temperature capability and good wear resistance. Friction stir welding (FSW) process parameters play major role in deciding the performance of welded joints. The ultimate tensile strength, notch tensile strength and weld nugget hardness of friction stir butt welded joints of cast A1/SiCp MMCs (AA6061 with 20% (volume fraction) of SiCp) were investigated. The relationships between the FSW process parameters (rotational speed, welding speed and axial force) and the responses (ultimate tensile strength, notch tensile strength and weld nugget hardness) were established. The optimal welding parameters to maximize the mechanical properties were identified by using desirability approach. From this investigation, it is found that the joints fabricated with the tool rotational speed of 1370 r/min, welding speed of 88.9 mm/min, and axial force of 9.6 kN yield the maximum ultimate tensile strength, notch tensile strength and hardness of 265 MPa, 201 MPa and HV 114, respectively. 展开更多
关键词 metal matrix composites friction stir welding A1/SiCp composites microstructure
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Plant growth-promoting rhizobacteria(PGPR)and its mechanisms against plant diseases for sustainable agriculture and better productivity 被引量:2
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作者 PRANAB DUTTA GOMATHY MUTHUKRISHNAN +12 位作者 SABARINATHAN KUTALINGAM GOPALASUBRAMAIAM rajakumar DHARMARAJ ANANTHI KARUPPAIAH KARTHIBA LOGANATHAN KALAISELVI PERIYASAMY MARUMUGAM PILLAI GK UPAMANYA SARODEE BORUAH LIPA DEB ARTI KUMARI MADHUSMITA MAHANTA PUNABATI HEISNAM AK MISHRA 《BIOCELL》 SCIE 2022年第8期1843-1859,共17页
Plant growth-promoting rhizobacteria(PGPR)are specialized bacterial communities inhabiting the root rhizosphere and the secretion of root exudates helps to,regulate the microbial dynamics and their interactions with t... Plant growth-promoting rhizobacteria(PGPR)are specialized bacterial communities inhabiting the root rhizosphere and the secretion of root exudates helps to,regulate the microbial dynamics and their interactions with the plants.These bacteria viz.,Agrobacterium,Arthobacter,Azospirillum,Bacillus,Burkholderia,Flavobacterium,Pseudomonas,Rhizobium,etc.,play important role in plant growth promotion.In addition,such symbiotic associations of PGPRs in the rhizospheric region also confer protection against several diseases caused by bacterial,fungal and viral pathogens.The biocontrol mechanism utilized by PGPR includes direct and indirect mechanisms direct PGPR mechanisms include the production of antibiotic,siderophore,and hydrolytic enzymes,competition for space and nutrients,and quorum sensing whereas,indirect mechanisms include rhizomicrobiome regulation via.secretion of root exudates,phytostimulation through the release of phytohormones viz.,auxin,cytokinin,gibberellic acid,1-aminocyclopropane-1-carboxylate and induction of systemic resistance through expression of antioxidant defense enzymes viz.,phenylalanine ammonia lyase(PAL),peroxidase(PO),polyphenyloxidases(PPO),superoxide dismutase(SOD),chitinase andβ-glucanases.For the suppression of plant diseases potent bio inoculants can be developed by modulating the rhizomicrobiome through rhizospheric engineering.In addition,understandings of different strategies to improve PGPR strains,their competence,colonization efficiency,persistence and its future implications should also be taken into consideration. 展开更多
关键词 Plant growth-promoting rhizobacteria BIOCONTROL Plant diseases PGPR mechanisms Sustainable agriculture
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Fracture strength of centre surface cracked tensile specimens made of 2219-T87 Al alloy welding 被引量:2
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作者 S. rajakumar T. CHRISTOPHER 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第12期2568-2575,共8页
Fracture data of both parent metal and weldment metals from surface cracked tensile plates made of 2219-T87 Al alloy at cryogenic temperatures were correlated using a modified inherent flaw model. Fracture parameters ... Fracture data of both parent metal and weldment metals from surface cracked tensile plates made of 2219-T87 Al alloy at cryogenic temperatures were correlated using a modified inherent flaw model. Fracture parameters to generate the failure assessment diagram were determined for the material. Fracture analysis was carried out considering the ultimate tensile strength value and the fracture data of aluminium base metal and weldment metal generated from center–surface cracked tensile specimens having different thicknesses. The failure assessment diagram of a material generated from tensile fracture plate configuration can be applied to failure pressure estimation of any cracked component, made of the same material. 展开更多
关键词 centre through crack tensile specimen failure assessment diagram fracture strength inherent flaw model 2219-T87 Al alloy
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Larvicidal activity of green synthesized silver nanoparticles using bark aqueous extract of Ficus racemosa against Culex quinquefasciatus and Culex gelidus 被引量:2
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作者 Kanayairam Velayutham Abdul Abdul Rahuman +8 位作者 Govindasamy rajakumar Selvaraj Mohana Roopan Gandhi Elango Chinnaperumal Kamaraj Sampath Marimuthu Thirunavukkarasu Santhoshkumar Moorthy Iyappan Chinnadurai Siva 《Asian Pacific Journal of Tropical Medicine》 SCIE CAS 2013年第2期95-101,共7页
Objective:To investigate the larvicidal activity of synthesized silver nanoparticles(Ag NPs) utilizing aqueous bark extract of Ficus racemosa(F.racemosa) was tested against fourth instar larvae of filariasis vecto... Objective:To investigate the larvicidal activity of synthesized silver nanoparticles(Ag NPs) utilizing aqueous bark extract of Ficus racemosa(F.racemosa) was tested against fourth instar larvae of filariasis vector,Culex quinquefasciatus(Cx.quinquefasciatus) and japanese encephalitis vectors,Culex gelidus(Cx.gelidus).Methods:The synthesized Ag NPs was characterized by UV-vis spectrum,X-ray diffraction(XRD),Scanning electron microscopy(SEM) and Fourier transform infrared(FTIR).The larvicidal activities were assessed for 24 h against the larvae of Cx.quinquefasciatus and Cx.gelidus with varying concentrations of aqueous bark extract off.racemosa and synthesized Ag NPs.LC<sub>50</sub> and r<sup>2</sup> values were calculated.Results:The maximum efficacy was observed in crude aqueous extract of F.racemosa against the larvae of Cx.quinquefasciatus and Cx.gelidus(LC<sub>50</sub>=67.72 and 63.70 mg/L;r<sup>2</sup>=0.995 and 0.985) and the synthesized Ag NPs(LC<sub>50</sub>=12.00 and 11.21 mg/L;r<sup>2</sup>=0.997 and 0.990).respectively.Synthesized Ag NPs showed the XRD peaks at 2θvalues of 27.61,29.60,35.48,43.48 and 79.68 were identified as (210),(121),(220),(200) and(311) reflections,respectively.The FTIR spectra of Ag NPs exhibited prominent peaks at 3 425,2 878,1 627 and 1 382 in the region 500-3 000 cm<sup>-1</sup>.The peaks correspond to the presence of a stretching vibration of(NH) C=O group.SEM analysis showed shape in cylindrical,uniform and rod with the average size of 250.60 nm.Conclusions:The biosynthesis of silver nanoparticles using bark aqueous extract of F.racemosa and its larvicidal activity against the larvae of disease spreading vectors.The maximum larvicidal efficacy was observed in the synthesized Ag NPs. 展开更多
关键词 FICUS racemosa CULEX quinquefasciatus CULEX gelidus Electron MICROSCOPIC study
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Electrocatalytic reduction of ortho nitrobenzaldehyde using modified aluminum electrode and its determination
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作者 Vairamuthu Raj Jayachandran Silambarasan Panchanathan rajakumar 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2014年第7期1531-1539,共9页
A simple, cost effective and rapid electrochemical method has been developed for the determination of micro level ortho nitrobenzaldehyde(ONB) based on outstanding properties of modified aluminum electrode tin nanor... A simple, cost effective and rapid electrochemical method has been developed for the determination of micro level ortho nitrobenzaldehyde(ONB) based on outstanding properties of modified aluminum electrode tin nanorods/anodic aluminum oxide/aluminum(SnNR/AAO/Al) for the first time. The SnNR/AAO/Al electrode was fabricated by a second step anodization, followed by electrodeposition and its electrochemical behavior was investigated in detail. The cyclic voltammetry results indicated that the SnNR/AAO/Al electrode exhibited efficient electrocatalytic activity toward reduction of ONB in the acidic solution. It provides an appreciable improvement of reduction peak for ONB at-0.721 V.Furthermore, various kinetic parameters such as transfer electron number, transfer proton number and standard heterogeneous rate constant were calculated from the scan rates.The electrocatalytic behavior was further exploited as a sensitive detection scheme for the ONB determination by differential pulse voltammetry. Under the optimized conditions, the concentration range and detection limit are 0.1-100 μmol/L and 0.05 μmol/L, respectively,for ONB. The analytical performance of this modified sensor has been evaluated for detection of real sample such as river water and recovery of ONB was achieved all-out up to102.3% under standard addition method. 展开更多
关键词 Electrochemical sensor Organic pollutant Aluminum electrode Anodic aluminum oxide Tin nanorods Ortho nitrobenzaldehyde Cyclic voltammetry
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Stress corrosion cracking behaviour of gas tungsten arc welded super austenitic stainless steel joints
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作者 M.VINOTH KUMAR V.BALASUBRAMANIAN +1 位作者 S.rajakumar SHAJU K.ALBERT 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2015年第3期282-291,共10页
Super 304 H austenitic stainless steel with 3% of copper posses excellent creep strength and corrosion resistance, which is mainly used in heat exchanger tubing of the boiler. Heat exchangers are used in nuclear power... Super 304 H austenitic stainless steel with 3% of copper posses excellent creep strength and corrosion resistance, which is mainly used in heat exchanger tubing of the boiler. Heat exchangers are used in nuclear power plants and marine vehicles which are intended to operate in chloride rich offshore environment. Chloride stress corrosion cracking is the most likely life limiting failure with austenitic stainless steel tubing. Welding may worsen the stress corrosion cracking susceptibility of the material. Stress corrosion cracking susceptibility of Super 304 H parent metal and gas tungsten arc(GTA) welded joints were studied by constant load tests in 45% boiling Mg Cl2 solution. Stress corrosion cracking resistance of Super 304 H stainless steel was deteriorated by GTA welding due to the formation of susceptible microstructure in the HAZ of the weld joint and the residual stresses. The mechanism of cracking was found to be anodic path cracking, with transgranular nature of crack propagation. Linear relationships were derived to predict the time to failure by extrapolating the rate of steady state elongation. 展开更多
关键词 奥氏体不锈钢管 应力腐蚀裂纹 钨极氩弧焊 开裂行为 钢接头 开裂敏感性 焊接接头 应力腐蚀开裂
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Fingerprint Agreement Using Enhanced Kerberos Authentication Protocol on M-Health
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作者 A.S.Anakath S.Ambika +2 位作者 S.rajakumar R.Kannadasan K.S.Sendhil Kumar 《Computer Systems Science & Engineering》 SCIE EI 2022年第11期833-847,共15页
Cloud computing becomes an important application development platform for processing user data with high security.Service providers are accustomed to providing storage centers outside the trusted location preferred by... Cloud computing becomes an important application development platform for processing user data with high security.Service providers are accustomed to providing storage centers outside the trusted location preferred by the data owner.Thus,ensuring the security and confidentiality of the data while processing in the centralized network is very difficult.The secured key transmission between the sender and the receiver in the network is a huge challenge in managing most of the sensitive data transmission among the cloud network.Intruders are very active over the network like real authenticated user to hack the personal sensitive data,such as bank balance,health data,personal data,and confidential documents over the cloud network.In this research,a secured key agreement between the sender and the receiver using Kerberos authentication protocol with fingerprint is proposed to ensure security in M-Healthcare.Conditions of patients are monitored using wireless sensor devices and are then transferred to the server.Kerberos protocol helps in avoiding unnecessary communication of authenticated data over the cloud network.Biometric security process is a procedure with the best security in most of the authentication field.Trust node is responsible in carrying data packets from the sender to the receiver in the cloud network.The Kerberos protocol is used in trust node to ensure security.Secured communication between the local health center and the healthcare server is ensured by using a fingerprint feature called minutiae form,which refers to the fingerprint image of both sender and receiver.The computational and communicational cost of the proposed system is lesser when compared with other existing authentication methods. 展开更多
关键词 Protocol security m-health cloud computing BIOMETRIC FINGERPRINT kerberos protocol
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Web-based remote sensing image retrieval using multiscale and multidirectional analysis based on Contourlet and Haralick texture features
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作者 rajakumar Krishnan Arunkumar Thangavelu +3 位作者 P.Prabhavathy Devulapalli Sudheer Deepak Putrevu Arundhati Misra 《International Journal of Intelligent Computing and Cybernetics》 EI 2021年第4期533-549,共17页
Purpose-Extracting suitable features to represent an image based on its content is a very tedious task.Especially in remote sensing we have high-resolution images with a variety of objects on the Earth’s surface.Maha... Purpose-Extracting suitable features to represent an image based on its content is a very tedious task.Especially in remote sensing we have high-resolution images with a variety of objects on the Earth’s surface.Mahalanobis distance metric is used to measure the similarity between query and database images.The low distance obtained image is indexed at the top as high relevant information to the query.Design/methodology/approach-This paper aims to develop an automatic feature extraction system for remote sensing image data.Haralick texture features based on Contourlet transform are fused with statistical features extracted from the QuadTree(QT)decomposition are developed as feature set to represent the input data.The extracted features will retrieve similar images from the large image datasets using an image-based query through the web-based user interface.Findings-The developed retrieval system performance has been analyzed using precision and recall and F1 score.The proposed feature vector gives better performance with 0.69 precision for the top 50 relevant retrieved results over other existing multiscale-based feature extraction methods.Originality/value-The main contribution of this paper is developing a texture feature vector in a multiscale domain by combining the Haralick texture properties in the Contourlet domain and Statistical features using QT decomposition.The features required to represent the image is 207 which is very less dimension compare to other texture methods.The performance shows superior than the other state of art methods. 展开更多
关键词 Image retrieval Remote sensing CONTOURLET Texture features Web-based search CBIR Multiscale texture
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Antioxidant and Cytotoxic Activities of A Novel Isomeric Molecule(PF5)Obtained from Methanolic Extract of Pleurotus Florida Mushroom
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作者 D.Menaga Pattanathu K.S.M.Rahman +1 位作者 S.rajakumar P.M.Ayyasamy 《Journal of Bioresources and Bioproducts》 EI 2021年第4期338-349,共12页
The Pleurotus florida is recognized as a medicinal and edible mushroom and the present study intends to reveal the active isomeric molecules from this mushroom.The P.florida was cultivated using different nutrient sup... The Pleurotus florida is recognized as a medicinal and edible mushroom and the present study intends to reveal the active isomeric molecules from this mushroom.The P.florida was cultivated using different nutrient supplements:groundnut husk,maize powder,horse gram powder and coconut oil-cake powder.Horse gram supplement showed the higher mushroom yield and henceit was used for the cultivation of P.florida.Methanolic extract of P.florida was found to be efficient in antioxidant activity among ethanol,aqueous,ethyl acetate and hexane extracts.The bioactive fraction 3-methoxy-4-hydroxy cinnamic acid(PF5)was isolated and purified from the methanolic extract of P.florida by column chromatography,thin layer chromatography(TLC)and gas chromatography-mass spectrum(GC-MS)and further it was characterized by Nuclear magnetic resonance(NMR).The PF5 was tested for its DPPH and reducing power assays,and the IC_(50) values were found to be 21.7μg/mL and 105μg/mL,respectively.We found that the cytotoxic effect of 3-methoxy-4-hydroxy cinnamic acid was tested against the lung cancer cell line using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT),sulphorodamine B(SRB)and trypan blue assays which exhibited a higher cytotoxic effect(CTC_(50),645μg/mL).These results suggested that 3-methoxy-4-hydroxy cinnamic acid from P.florida could be explored as a novel and potent natural antioxidant and cancer preventive agent,alternative to existing synthetic molecules. 展开更多
关键词 Pleurotus florida Methanolic extract Isomeric molecule Antioxidant activity Cytotoxic activity
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An Efficient Modelling of Oversampling with Optimal Deep Learning Enabled Anomaly Detection in Streaming Data
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作者 R.rajakumar S.Sathiya Devi 《China Communications》 SCIE CSCD 2024年第5期249-260,共12页
Recently,anomaly detection(AD)in streaming data gained significant attention among research communities due to its applicability in finance,business,healthcare,education,etc.The recent developments of deep learning(DL... Recently,anomaly detection(AD)in streaming data gained significant attention among research communities due to its applicability in finance,business,healthcare,education,etc.The recent developments of deep learning(DL)models find helpful in the detection and classification of anomalies.This article designs an oversampling with an optimal deep learning-based streaming data classification(OS-ODLSDC)model.The aim of the OSODLSDC model is to recognize and classify the presence of anomalies in the streaming data.The proposed OS-ODLSDC model initially undergoes preprocessing step.Since streaming data is unbalanced,support vector machine(SVM)-Synthetic Minority Over-sampling Technique(SVM-SMOTE)is applied for oversampling process.Besides,the OS-ODLSDC model employs bidirectional long short-term memory(Bi LSTM)for AD and classification.Finally,the root means square propagation(RMSProp)optimizer is applied for optimal hyperparameter tuning of the Bi LSTM model.For ensuring the promising performance of the OS-ODLSDC model,a wide-ranging experimental analysis is performed using three benchmark datasets such as CICIDS 2018,KDD-Cup 1999,and NSL-KDD datasets. 展开更多
关键词 anomaly detection deep learning hyperparameter optimization OVERSAMPLING SMOTE streaming data
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A Novel Outlier Detection with Feature Selection Enabled Streaming Data Classification
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作者 R.rajakumar S.Sathiya Devi 《Intelligent Automation & Soft Computing》 SCIE 2023年第2期2101-2116,共16页
Due to the advancements in information technologies,massive quantity of data is being produced by social media,smartphones,and sensor devices.The investigation of data stream by the use of machine learning(ML)approach... Due to the advancements in information technologies,massive quantity of data is being produced by social media,smartphones,and sensor devices.The investigation of data stream by the use of machine learning(ML)approaches to address regression,prediction,and classification problems have received consid-erable interest.At the same time,the detection of anomalies or outliers and feature selection(FS)processes becomes important.This study develops an outlier detec-tion with feature selection technique for streaming data classification,named ODFST-SDC technique.Initially,streaming data is pre-processed in two ways namely categorical encoding and null value removal.In addition,Local Correla-tion Integral(LOCI)is used which is significant in the detection and removal of outliers.Besides,red deer algorithm(RDA)based FS approach is employed to derive an optimal subset of features.Finally,kernel extreme learning machine(KELM)classifier is used for streaming data classification.The design of LOCI based outlier detection and RDA based FS shows the novelty of the work.In order to assess the classification outcomes of the ODFST-SDC technique,a series of simulations were performed using three benchmark datasets.The experimental results reported the promising outcomes of the ODFST-SDC technique over the recent approaches. 展开更多
关键词 Streaming data classification outlier removal feature selection machine learning metaheuristics
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