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Design and analysis of high birefringence and nonlinearity with small confinement loss photonic crystal fiber

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Frontiers of Optoelectronics 2019年第2期12卷 165-173页

作者： Rekha SAHA Md.Mahbub HOSSAIN Md. Ekhlasur RAHAMAN Himadri shekhar mondal Electronics and Communication Engineering Discipline Khulna UniversityKhulna 9208Bangladesh

High birefringence with low confinement loss photonic crystal fiber (PCF) has significant advantages in the field of sensing, dispersion compensation devices, nonlinear applications, and polarization filter. In this report, two different models of PCFs are presented and compared. Both the models contain five air holes rings with combination of circular and elliptical air holes arrangement. Moreover, the elliptical shaped air holes polarization and the third ring air holes rotational angle are varied. To examine different guiding characteristics, finite element method (FEM) with perfectly matched layer (PML) absorbing boundary condition is applied from 1.2 to 1.8 |im wavelength range. High birefringence, low confinement loss, high nonlinearity, and moderate disper-sion values are successfully achieved in both the PCFs models. Numeric analysis shows that model-1 gives higher birefringence (2.75 ×10^-2) and negative dispersion (-540.67 ps/(nm ·km)) at 1.55 |im wavelength. However, model-2 gives more small confinement loss than model-1 at the same wavelength. In addition, the proposed design demonstrates the variation of rotation angle has great impact to enhance guiding properties especially the birefringence.

关键词： birefringence dispersion polarization main-taining photonic crystal fiber (PCF) polarization-selective devices polarization

Chemical sensing through photonic crystal fiber:sulfuric acid detection

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Frontiers of Optoelectronics 2019年第4期12卷 372-381页

作者： Etu PODDER Md.Belial HOSSAIN Rayhan Habib JIBON Abdullah Al-Mamun BULBUL Himadri shekhar mondal Electronics and Communication Engineering Discipline Khulna UniversityKhulna-9208Bangladesh Department of Electronics and Telecommunication Engineering(ETE) Bangabandhu Sheikh Mujibur Rahman Science and Technology UniversityGopalganjBangladesh

A photonic crystal fiber(PCF)for sensing of sulfuric acid is designed and analyzed using Comsol *** analyze the sensor performance,0%,10%,20%,30%,40%H2SO4 solution is placed into the fiber separately and then relative sensitivity,confinement loss,birefringence,effective area *** investigated for each solution over wavelength ranging from 0.8 to 1.8μ*** sensor structure affords moderately high relative sensitivity and around 63.4%sensitivity is achieved for the highest concentration of H2SO4 at the wavelength 1.5|im inxpolarization *** PCF model also shows zero confinement loss for all solutions of H2SO4 over wavelength ranging from 1 to 1.35μm and later on approximately 1.422×10^-17 dB/km confinement loss is found for the highest concentration of H2SO4 at 1.5|im ***,higher birefringence is attained when the concentration of sulfuric acid is lower and it is achieved 7.5×10^-4 at 1.5μm ***,higher sensing area is achieved at high concentration of sulfuric acid.

关键词： refractive index confinement loss birefri gence relative sensitivity

Clinical profile and outcomes of hepatocellular carcinoma in primary Budd-Chiari syndrome

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World Journal of Gastrointestinal Oncology 2024年第3期16卷 699-715页

作者： Ankit Agarwal Sagnik Biswas shekhar Swaroop Arnav Aggarwal Ayush Agarwal Gautam Jain Anshuman Elhence Arun Vaidya Amit Gupte Ravi Mohanka Ramesh Kumar Ashwani Kumar Mishra Shivanand Gamanagatti Shashi Bala Paul Subrat Kumar Acharya Akash Shukla Shalimar Department of Gastroenterology and Human Nutrition All India Institute of Medical SciencesNew Delhi 110029DelhiIndia Department of Gastroenterology Seth Gordhandas Sunderdas Medical College and KEM HospitalMumbai 400012MaharashtraIndia Department of Gastroenterology Sir HN Reliance Foundation HospitalMumbai 400004India Department of Liver Transplant and HPB Sir HN Reliance Foundation HospitalMumbai 400004India Department of Gastroenterology All India Institute of Medical SciencesPatna 801507India Professor of Biostatistics National Drug Dependence Treatment Centre(NDDTC)All India Institute of Medical SciencesNew Delhi 110029India Department of Radiodiagnosis All India Institute of Medical SciencesNew Delhi 110029DelhiIndia

BACKGROUND There is scant literature on hepatocellular carcinoma(HCC)in patients with Budd-Chiari syndrome(BCS).AIM To assess the magnitude,clinical characteristics,feasibility,and outcomes of treatment in *** A total of 904 BCS patients from New Delhi,India and 1140 from Mumbai,India were *** prevalence and incidence of HCC were determined,and among patients with BCS-HCC,the viability and outcomes of interventional therapy were *** In the New Delhi cohort of 35 BCS-HCC patients,18 had HCC at index presentation(prevalence 1.99%),and 17 developed HCC over a follow-up of 4601 person-years,[incidence 0.36(0.22-0.57)per 100 person-years].BCS-HCC patients were older when compared to patients with BCS alone(P=0.001)and had a higher proportion of inferior vena cava block,cirrhosis,and long-segment vascular *** median alpha-fetoprotein level was higher in patients with BCS-HCC at first presentation than those who developed HCC at follow-up(13029 ng/mL vs 500 ng/mL,P=0.01).Of the 35 BCS-HCC,26(74.3%)underwent radiological interventions for BCS,and 22(62.8%)patients underwent treatment for HCC[transarterial chemoembolization in 18(81.8%),oral tyrosine kinase inhibitor in 3(13.6%),and transarterial radioembolization in 1(4.5%)].The median survival among patients who underwent interventions for HCC compared with those who did not was 3.5 years vs 3.1 mo(P=0.0001).In contrast to the New Delhi cohort,the Mumbai cohort of BCS-HCC patients were predominantly males,presented with a more advanced HCC[Barcelona Clinic Liver Cancer C and D],and 2 patients underwent liver *** HCC is not uncommon in patients with *** interventions and liver transplantation are feasible in select primary BCS-HCC patients and may improve outcomes.

关键词： Budd chiari syndrome Cancer Cirrhosis Thrombosis Liver Varices Transarterial chemoembolization Hepatic venous outflow tract obstruction

Applicability of unique scarf joint configuration in friction stir welding of AA6061-T6:Analysis of torque,force,microstructure and mechanical properties

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Defence Technology（防务技术） 2022年第4期18卷 567-582页

作者： Durjyodhan Sethi Uttam Acharya Shashank shekhar Barnik Saha Roy Department of Mechanical Engineering National Institute of Technology AgartalaBarjalaJiraniaWest TripuraPin-799046India Department of Materials Science and Engineering Indian Institute of Technology KanpurKanpur208016India

The present research introduces a unique concept of scarf joint technique in friction stir welding(FSW) of aluminum alloy AA 6061-T6 plates and an investigation on weld quality.A new joint configuration with two distinct scarf angles(75°and 60°) was considered in this *** various aspects of welding were compared with contemporary simple square butt(SSB) joint *** was carried out at a constant tool rotation speed(TRS),tool traverse speed(TTS) and tool tilt angle of 1100 rpm,2 mm/s and2°,*** results are analyzed in terms of force and torque distribution,microstructure,macrostructure,and mechanical property perspective for different joint *** study reveals the minimum amount of force and torque at 60°scarf angle joint configuration compared to that of square butt joint *** study shows that all the joints were defect-free,and a prominent onion ring was present in the lower portion of the weld nugget(WN).Fine equiaxed grains with a minimum average grain size diameter of 6.82 μm were obtained in the WN of scarf joint configuration(SJC).The maximum ultimate tensile strength(UTS) and maximum average NZ hardness of 267 MPa and83.82 HV0.1were obtained in SJC3 at a scarf angle of 60°.It has been observed from the investigation that the joint efficiency increases from 72.5%(SSB) to 86%(SJC3) at a 60° scarf *** unique characteristic may lay an impetus on probable joint strength enhancement technique without increasing the production cost.

关键词： Friction stir welding Joint configuration Al alloys Force and torque Microstructure Mechanical property

Vertical impedance functions of pile groups under low-to-high loading amplitudes:numerical simulations and experimental validation

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Earthquake Engineering and Engineering Vibration 2023年第3期22卷 647-666页

作者： Usama Zafar Chandra shekhar Goit Masato Saitoh Riku Fukuda School of Science and Engineering Saitama University255 Shimo-OkuboSaitamaJapan

Piles in a group experience additional displacements in soil due to pile-to-pile interactions apart from those resulting from the external *** effect of these interactions determined assuming soil as an elastic and/or viscoelastic material on pile head impedance functions of the pile group is studied by relating the group stiffness to the static stiffness of a single ***,the prevailing elastic solutions may misestimate the resulting pile group response due to the lack of consideration for either soil(material)and/or soil-pile interface *** is well established that soil behaves nonlinearly under moderate-to-high loading amplitudes,and besides,the soil-pile interface nonlinearity can exist even at small loading *** study addresses the effects of these nonlinearities on the vertical impedance functions of a 3×3-pile group using numerical methods by direct analyses and superposition using pile-to-pile interaction *** numerical results are validated using scaled model tests under 1 g *** results highlight the overestimation of pile-to-pile interactions in the pile group when assuming elastic soil *** cases either by direct analyses or superposition approach involving soil and soil-pile interface nonlinearities agree well with the experimental pile group responses under close-to-elastic and nonlinear conditions.

关键词： impedance functions numerical simulations model-scale experiment superposition approach soil-pile interface nonlinearity

Enhanced microbial degradation of pyrene using biosurfactant isolated from Bacillus ***105

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Systems Microbiology and Biomanufacturing 2022年第4期2卷 723-731页

作者： Neha Maheshwari Indu shekhar Thakur Shaili Srivastava Amity School of Earth and Environmental Science Amity UniversityGurugramHaryanaIndia School of Environmental Sciences Jawaharlal Nehru UniversityNew Delhi 110067India

The present research work highlights the biosurfactant application toward enhanced pyrene degradation by Pseudomonas ***-type biosurfactant was produced from Free Air CO_(2) Enriched(FACE)soil bacterium Bacillus *** different concentrations of biosurfactant at different time intervals were optimized for maximum pyrene degradation and quantified through analytical methods such as the scanning process of UV-Vis spectrophotometer and GC-MS *** the absence of biosurfactant,Pseudomonas *** degrade only 8%of pyrene at the concentration of 5 mg per 100 ml,while the degradation rate enhanced by 95%in presence of biosurfactant(5 mg/100 ml of culture).This result demonstrated that biosurfactant produced from Bacillus ***105 has potential to enhance the bioavailability and biodegradation of pyrene by Pseudomonas sp.

关键词： Bacillus sp. Biosurfactant Degradation Pyrene

Exploring the potential of artificial intelligence techniques in prediction of the removal efficiency of vortex tube silt ejector

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International Journal of Sediment Research 2023年第4期38卷 615-627页

作者： Sanjeev Kumar Chandra shekhar Prasad Ojha Nand Kumar Tiwari Subodh Ranjan Department of Civil Engineering Indian Institute of Technology Department of Civil Engineering National Institute of Technology

A vortex tube silt ejector is a curative hydraulic structure used to remove sediment deposits from canals and is recognized as one of the most efficient substitutes for physically removing canal sediment. The spatially varied flow in the channel and the rotational flow behavior in the tube make the silt removal process complex. It is even harder to accurately predict the silt removal efficiency by traditional models accurately. However, artificial intelligence(AI) and machine learning approaches have emerged as robust substitutes for studying complex processes. Therefore, this research makes use of AI approaches; support vector machine(SVM), random forest(RF), random tree(RT), and multivariate adaptive regression spline(MARS) to compute the vortex tube silt ejection efficiency using the laboratory data sets. The outcomes of the artificial intelligence(AI)-based techniques also were compared with traditional models. It was found that the RT model(root mean square error, RMSE = 2.165, Nash Sutcliffe efficiency, NSE = 0.98) outperforms the other applied approaches which had relatively more significant result errors. The sensitivity analysis of the process depicts the extraction ratio as the key parameter in the computation of vortex tube silt ejector removal efficiency. The findings of the AI-based approaches discussed in the current study might be helpful for hydraulic engineers as well as researchers in the assessment of the removal efficiency of vortex tube silt ejectors.

关键词： Vortex tube silt ejector Support vector machine Random forest Random tree Multivariate adaptive regression spline

Identification and characterization of integron mediated antibiotic resistance in pentachlorophenol degrading bacterium isolated from the chemostat

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Journal of Environmental Sciences 2009年第6期21卷 858-864页

作者： SHARMA Ashwani THAKUR Indu shekhar Environmental Biotechnology Laboratory School of Environmental SciencesJawaharlal Nehru UniversityNew Mehrauli Road

A bacterial consortium was developed by continuous enrichment of microbial population isolated from sediment core of pulp and paper mill effluent in mineral salts medium（MSM） supplemented with pentachlorophenol（PCP） as sole source of carbon and energy in the *** consortia contained three bacterial *** were identified as Escherichia coli,Pseudomonas aeruginosa and Acinetobacter *** 16S rRNA gene sequence *** *** degraded PCP through the formation of tetrachloro-p-hydroquinone（TecH）,2-chloro-1,4-benzenediol and products of ortho ring cleavage detected by gas chromatograph/mass spectrometer（GC-MS）.Out of the three acclimated PCP degrading bacterial strains only one strain,Acinetobacter *** the presence of integron gene cassette as a marker of its stability and antibiotic *** strain possessed a 4.17 kb amplicon with 22 ORF＇*** plasmid isolated from the Acinetobacter *** subjected to shotgun cloning through restriction digestion by BamHI,HindIII and SalI,ligated to pUC19 vector and transformed into *** XLBlue1α,and finally selected on MSM containing PCP as sole source of carbon and energy with ampicillin as antibiotic *** sequence analysis of recombinant clones indicated homology with integron gene cassette and multiple antibiotic resistance genes.

关键词： Acinetobacter sp. antibiotic resistance gene chemostat integron gene cassette pentachlorophenol recombinant clone

Model tests and numerical analyses on horizontal impedance functions of inclined single piles embedded in cohesionless soil

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Earthquake Engineering and Engineering Vibration 2013年第1期12卷 143-154页

作者： Chandra shekhar Goit Masato Saitoh Department of Civil and Environmental Engineering Saitama University

Horizontal impedance functions of inclined single piles are measured experimentally for model soil-pile systems with both the effects of local soil nonlinearity and resonant *** practical pile inclinations of 5掳 and 10掳 in addition to a vertical pile embedded in cohesionless soil and subjected to lateral harmonic pile head loadings for a wide range of frequencies are *** obtained with low-to-high amplitude of lateral loadings on model soil-pile systems encased in a laminar shear box show that the local nonlinearities have a profound impact on the horizontal impedance functions of *** impedance functions of inclined piles are found to be smaller than the vertical pile and the values decrease as the angle of pile inclination *** values of horizontal impedance functions are obtained for the ＇positive＇ and ＇negative＇ cycles of harmonic loadings,leading to asymmetric force-displacement relationships for the inclined *** of these experimental results is carried out through three-dimensional nonlinear finite element analyses,and the results from the numerical models are in good agreement with the experimental *** analyses conducted on the numerical models suggest that the consideration of local nonlinearity at the vicinity of the soil-pile interface influence the response of the soil-pile systems.

关键词： inclined single piles harmonic loads horizontal impedance functions local nonlinearity finite element model