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  • Walter de Gruyter GmbH  (5)
  • 1
    Online Resource
    Online Resource
    Novel in situ synthesis of quaternary core–shell metallic sulfide nanocomposites for degradation of organic dyes and hydrogen production
    Walter de Gruyter GmbH ; 2023
    In:  Green Processing and Synthesis Vol. 12, No. 1 ( 2023-05-08)
    Details
    In: Green Processing and Synthesis, Walter de Gruyter GmbH, Vol. 12, No. 1 ( 2023-05-08)
    Abstract: Environmental remediation of toxic organic pollutants on catalytic degradation has gained much attention. Organic dyes and fossil fuels as pollutants are the two major problems nowadays. The efficient and targeted eradication of organic dye from water systems is a critical global concern for the treatment of both drinking water and wastewater. In this study, ZnO–ZnS–CdO–CdS quaternary core–shell nanocomposites (NCs) were synthesized using Ricinus communis as a stabilizing agent and hydrazine hydrate as a reducing agent. UV-visible spectroscopy and photoluminescence confirmed the formation of NCs. Fourier transform infrared spectroscopy confirmed the presence of functional groups, while scanning electron microscopy analysis revealed that the morphology of nanomaterials was spherical and poly distributed. X-ray powder diffraction confirmed the crystalline nature of prepared samples. The prepared nanocatalysts were used in the production of hydrogen gas from green sources of the Brassica campestris leaf extract and the degradation of Congo red and methyl red dyes. Overall, the photocatalytic performance of NCs and their design was successful. The prepared catalysts were not only active in the degradation of a single substrate but also in the degradation of a mixture of dyes.
    Type of Medium: Online Resource
    ISSN: 2191-9550
    URL: Article
    DOI: 10.1515/gps-2022-8128
    Language: English
    Publisher: Walter de Gruyter GmbH
    Publication Date: 2023
    detail.hit.zdb_id: 2645923-1
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  • 2
    Online Resource
    Online Resource
    Green synthesis of manganese-doped superparamagnetic iron oxide nanoparticles for the effective removal of Pb(ii) from aqueous solutions
    Walter de Gruyter GmbH ; 2022
    In:  Green Processing and Synthesis Vol. 11, No. 1 ( 2022-04-01), p. 287-305
    Details
    In: Green Processing and Synthesis, Walter de Gruyter GmbH, Vol. 11, No. 1 ( 2022-04-01), p. 287-305
    Abstract: In the current study, pure and manganese-doped superparamagnetic iron oxide nanoparticles (Mn-doped SPIONPs) were successfully prepared by a green approach using a fresh aqueous extract of Asparagus officinalis as a reducing and stabilizing agent. Magnetic behaviors of pure and Mn-doped SPIONPs were measured at room temperature against various field strengths by a vibrating sample magnetometer (VSM). The saturation magnetization was in the range of 5.39–2.07 emu. Absorption at 340 nm in the UV-visible spectrum confirmed the presence of iron oxide nanoparticles (IONPs). The presence of plant extract as a capping agent was confirmed by Fourier transform infrared (FTIR) spectroscopy. The crystalline nature of IONPs was confirmed by X-ray diffraction. A gradual increase in size was observed with increasing concentration of Mn. The synthesized materials were applied successfully as sorbent for the effective removal of lead ions (Pb( ii )). Experimental results of adsorption were also analyzed by Langmuir and Freundlich isotherm equations at different temperatures. The results suggested that sorption processes were spontaneous, and the synthesized SPIONPs displayed Pb II removal capacity at higher loadings with q m of 21.3 and 29.56 mg·g −1 for undoped and 7% Mn-doped IOPNs, respectively, as compared to the commercial activated carbon.
    Type of Medium: Online Resource
    ISSN: 2191-9550
    URL: Article
    DOI: 10.1515/gps-2022-0030
    Language: English
    Publisher: Walter de Gruyter GmbH
    Publication Date: 2022
    detail.hit.zdb_id: 2645923-1
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  • 3
    Online Resource
    Online Resource
    Effects of Triangular Core Rotation of a Hybrid Porous Core Terahertz Waveguide
    Walter de Gruyter GmbH ; 2017
    In:  International Journal of Electronics and Telecommunications Vol. 63, No. 1 ( 2017-03-1), p. 25-31
    Details
    In: International Journal of Electronics and Telecommunications, Walter de Gruyter GmbH, Vol. 63, No. 1 ( 2017-03-1), p. 25-31
    Abstract: In this paper, we investigate the effects for rotating the triangular core air hole arrangements of a hybrid design porous core fiber. The triangular core has been rotated in anti-clockwise direction to evaluate the impact on different waveguide properties. Effective Material Loss (EML), confinement loss, bending loss, dispersion characteristics and fraction of power flow are calculated to determine the impacts for rotating the triangular core. The porous fiber represented here has a hybrid design in the core area which includes circular rings with central triangular air hole arrangement. The cladding of the investigated fiber has a hexagonal array of air hole distribution. For optimum parameters the reported hybrid porous core fiber shows a flat EML of ±0.000416 cm −1 from 1.5 to 5 terahertz (THz) range and a near zero dispersion of 0.4±0.042 ps/THz/cm from 1.25 to 5.0 THz. Negligible confinement and bending losses are reported for this new type of hybrid porous core design. With improved concept of air hole distribution and exceptional waveguide properties, the reported porous core fiber can be considered as a vital forwarding step in this field of research.
    Type of Medium: Online Resource
    ISSN: 2300-1933
    URL: Article
    DOI: 10.1515/eletel-2017-0004
    Language: Unknown
    Publisher: Walter de Gruyter GmbH
    Publication Date: 2017
    detail.hit.zdb_id: 2819080-4
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  • 4
    Online Resource
    Online Resource
    Performance Analysis of DPSK-OCDMA System for Optical Access Network
    Walter de Gruyter GmbH ; 2016
    In:  Journal of Optical Communications Vol. 37, No. 1 ( 2016-01-1)
    Details
    In: Journal of Optical Communications, Walter de Gruyter GmbH, Vol. 37, No. 1 ( 2016-01-1)
    Abstract: In this research, the performance of optical code division multiple access (OCDMA) using differential phase shift keying (DPSK) has been compared with OCDMA On-Off Keying (OOK). This comparison took place in terms of bit error rate (BER) and receiver power where two bit rates (155 Mbps and 622 Mbps) have been used for this analysis. Using of OptiSystem 7.0 simulation, comparing eye diagram and optical spectrum alongside with BER and Rx power. It is found that OCDMA-DPSK performs better in comparison to OCDMA-OOK. The performance analysis also provides parameter for designing and development of an OCDMA system for optical access network using DPSK.
    Type of Medium: Online Resource
    ISSN: 0173-4911 , 2191-6322
    URL: Article
    DOI: 10.1515/joc-2015-0014
    Language: Unknown
    Publisher: Walter de Gruyter GmbH
    Publication Date: 2016
    detail.hit.zdb_id: 2430977-1
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  • 5
    Online Resource
    Online Resource
    Performance Analysis of WDM-PON System Based on Optimized Remotely Pumped Erbium-Doped Fiber Amplifier (EDFA) Parameter
    Walter de Gruyter GmbH ; 2015
    In:  Journal of Optical Communications Vol. 36, No. 2 ( 2015-01-1)
    Details
    In: Journal of Optical Communications, Walter de Gruyter GmbH, Vol. 36, No. 2 ( 2015-01-1)
    Abstract: In this paper, the performance of wavelength division multiplexing-passive optical network (WDM-PON) system using the erbium-doped fiber amplifier (EDFA) is optimized and evaluated. The optimization is analyzed by finding the EDFA length range at which the output power produced are the highest and the pump power range at which the gain flatness produced are within the effective range (0.3 dB). After the optimization process, the optimized EDFA system produces the gain of 26.6±0.292 dB, noise figure of 3.82 dB and output power of 7 dBm and the system is then implemented into WDM system. The performance of WDM system is compared against the system without EDFA in terms of bit error rate (BER). Results obtained prove that the proposed system with the EDFA consistently performs better than the conventional system.
    Type of Medium: Online Resource
    ISSN: 0173-4911 , 2191-6322
    URL: Article
    DOI: 10.1515/joc-2014-0029
    Language: Unknown
    Publisher: Walter de Gruyter GmbH
    Publication Date: 2015
    detail.hit.zdb_id: 2430977-1
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