Abstract A new photoluminescence material, tris (5-Choloro 8-hydroxy quinoline) lanthanum has bee... more Abstract A new photoluminescence material, tris (5-Choloro 8-hydroxy quinoline) lanthanum has been synthesized and characterized by different techniques. The prepared material La(5-Clq) 3 was characterized for structural, thermal and photoluminescence analysis. Structural analysis of this material was done by fourier transformed infrared spectroscopy (FTIR) and mass spectroscopy. Thermal analysis of this material was done by thermal gravimetric analysis (TGA) shows the thermal stability up to 180°C.Absorption and emission spectra of the material was measured by UV-visible spectroscopy and photoluminescence spectroscopy. Solution of this material La(5-Clq) 3 in ethanol showed absorption peaks at 350nm and 395nm respectively which may be attributed due to ( π – π∗) transitions. The photoluminescence spectra of La (5-Clq) 3 in ethanol solution showed intense peak at 515 nm.
A new ceramic forming process, protein coagulation casting (PCC), has been applied for consolidat... more A new ceramic forming process, protein coagulation casting (PCC), has been applied for consolidation of green silicon carbide bodies. The process utilizes aqueous ceramic slurries based on egg white (ovalbumin). The silicon carbide powder was dispersed in an aqueous medium without any pH adjustment or addition of any dispersing agents. The ovalbumin based slurries could be gelled simply by heating without use of any chemical additives and it provided sufficient strength for handling the bodies. An addition of ovalbumin to aqueous silicon carbide slurries enhanced the viscosity and thus limited the solid loading. The ovalbumin containing slurries were thixotropic in nature. With the use of the present process, defect free near-net shaped silicon carbide bodies were prepared.
Purpose Electron beam-based additive manufacturing (EBAM) is an emerging technology to produce me... more Purpose Electron beam-based additive manufacturing (EBAM) is an emerging technology to produce metal parts layer-by-layer. The purpose of this paper is to systematically address the research and development carried out for this technology, up till now. Design/methodology/approach This paper identifies several aspects of research and development in EBAM. Findings Electron beam has several unique advantages such as high scanning speed, energy efficiency, versatility for several materials and better part integrity because of a vacuum working environment. Originality/value This paper provides information on different aspects of EBAM with the current status and future scope.
Microstructure and properties of sintered components produced from nanoparticulate materials are ... more Microstructure and properties of sintered components produced from nanoparticulate materials are critically dependent on degree of deagglomeration of particulates prior to their consolidation. While all nanoparticulate materials have an inherent tendency to agglomerate owing to attractive Van der Waals forces the impact of agglomeration on sintering behavior/sintered density of powder compacts and associated properties is significant. Although a lot of work has been carried out on developing approaches to deagglomeration of nanopowders it is a challenging task to evaluate the extent of deagglomeration by examining powder compacts. Microscopy of powders (TEM) or of compacts (SEM) is unable to provide any clear distinction between powders with different degrees of particulate agglomeration/deagglomeration. The present chapter cites two case studies from processing of dye sensitized solar cells and synthesis of nanocrystalline yttria stabilized zirconia (YSZ) powders respectively to illustrate that nanoindentation can be an effective way of characterizing the impact of deagglomeration approaches and the consequent deagglomeration extent on powders and compact characteristics. Electrical characterization of the titania based dye-sensitized solar cells, characteristics of green and sintered compacts prepared from synthesized nano YSZ powders are supported by observations from nanoindentation studies.
Synthesis of a series of new organic photosensitizers, designated as BZ1‐BZ4, was achieved by inc... more Synthesis of a series of new organic photosensitizers, designated as BZ1‐BZ4, was achieved by incorporating benzofuran core as π‐spacer, triphenylamine (TPA) and 4‐methoxy triphenylamine (4‐MeO‐TPA) as donors and cyanoacrylic acid (CAA) and rhodanine‐3‐acetic acid (RAA) as acceptor/anchoring groups. Structurally, dyes BZ1 and BZ2 carry TPA and 4‐MeO‐TPA as donors, respectively, whereas CAA constitutes as a common acceptor. On the other hand, BZ3 and BZ4 incorporate TPA and 4‐MeO‐TPA as donors, respectively, and RAA serves as a common acceptor. Key steps to access BZ1‐BZ4 involved Wittig olefination, reduction of cyano groups to aldehyde, and finally Knoevenagel condensation. In UV–visible spectra, dyes BZ1‐BZ4 exhibited intramolecular charge transfer (ICT) maxima in the range of 503 nm to 534 nm and their extinction coefficients varied from 22,600 to 40,400 M−1 cm−1. Using cyclic voltammetry and UV–visible data, we calculated the optical band gaps, (E0−0) of BZ1‐BZ4 to be 2.09, 2.00...
Abstract A new photoluminescence material, tris (5-Choloro 8-hydroxy quinoline) lanthanum has bee... more Abstract A new photoluminescence material, tris (5-Choloro 8-hydroxy quinoline) lanthanum has been synthesized and characterized by different techniques. The prepared material La(5-Clq) 3 was characterized for structural, thermal and photoluminescence analysis. Structural analysis of this material was done by fourier transformed infrared spectroscopy (FTIR) and mass spectroscopy. Thermal analysis of this material was done by thermal gravimetric analysis (TGA) shows the thermal stability up to 180°C.Absorption and emission spectra of the material was measured by UV-visible spectroscopy and photoluminescence spectroscopy. Solution of this material La(5-Clq) 3 in ethanol showed absorption peaks at 350nm and 395nm respectively which may be attributed due to ( π – π∗) transitions. The photoluminescence spectra of La (5-Clq) 3 in ethanol solution showed intense peak at 515 nm.
A new ceramic forming process, protein coagulation casting (PCC), has been applied for consolidat... more A new ceramic forming process, protein coagulation casting (PCC), has been applied for consolidation of green silicon carbide bodies. The process utilizes aqueous ceramic slurries based on egg white (ovalbumin). The silicon carbide powder was dispersed in an aqueous medium without any pH adjustment or addition of any dispersing agents. The ovalbumin based slurries could be gelled simply by heating without use of any chemical additives and it provided sufficient strength for handling the bodies. An addition of ovalbumin to aqueous silicon carbide slurries enhanced the viscosity and thus limited the solid loading. The ovalbumin containing slurries were thixotropic in nature. With the use of the present process, defect free near-net shaped silicon carbide bodies were prepared.
Purpose Electron beam-based additive manufacturing (EBAM) is an emerging technology to produce me... more Purpose Electron beam-based additive manufacturing (EBAM) is an emerging technology to produce metal parts layer-by-layer. The purpose of this paper is to systematically address the research and development carried out for this technology, up till now. Design/methodology/approach This paper identifies several aspects of research and development in EBAM. Findings Electron beam has several unique advantages such as high scanning speed, energy efficiency, versatility for several materials and better part integrity because of a vacuum working environment. Originality/value This paper provides information on different aspects of EBAM with the current status and future scope.
Microstructure and properties of sintered components produced from nanoparticulate materials are ... more Microstructure and properties of sintered components produced from nanoparticulate materials are critically dependent on degree of deagglomeration of particulates prior to their consolidation. While all nanoparticulate materials have an inherent tendency to agglomerate owing to attractive Van der Waals forces the impact of agglomeration on sintering behavior/sintered density of powder compacts and associated properties is significant. Although a lot of work has been carried out on developing approaches to deagglomeration of nanopowders it is a challenging task to evaluate the extent of deagglomeration by examining powder compacts. Microscopy of powders (TEM) or of compacts (SEM) is unable to provide any clear distinction between powders with different degrees of particulate agglomeration/deagglomeration. The present chapter cites two case studies from processing of dye sensitized solar cells and synthesis of nanocrystalline yttria stabilized zirconia (YSZ) powders respectively to illustrate that nanoindentation can be an effective way of characterizing the impact of deagglomeration approaches and the consequent deagglomeration extent on powders and compact characteristics. Electrical characterization of the titania based dye-sensitized solar cells, characteristics of green and sintered compacts prepared from synthesized nano YSZ powders are supported by observations from nanoindentation studies.
Synthesis of a series of new organic photosensitizers, designated as BZ1‐BZ4, was achieved by inc... more Synthesis of a series of new organic photosensitizers, designated as BZ1‐BZ4, was achieved by incorporating benzofuran core as π‐spacer, triphenylamine (TPA) and 4‐methoxy triphenylamine (4‐MeO‐TPA) as donors and cyanoacrylic acid (CAA) and rhodanine‐3‐acetic acid (RAA) as acceptor/anchoring groups. Structurally, dyes BZ1 and BZ2 carry TPA and 4‐MeO‐TPA as donors, respectively, whereas CAA constitutes as a common acceptor. On the other hand, BZ3 and BZ4 incorporate TPA and 4‐MeO‐TPA as donors, respectively, and RAA serves as a common acceptor. Key steps to access BZ1‐BZ4 involved Wittig olefination, reduction of cyano groups to aldehyde, and finally Knoevenagel condensation. In UV–visible spectra, dyes BZ1‐BZ4 exhibited intramolecular charge transfer (ICT) maxima in the range of 503 nm to 534 nm and their extinction coefficients varied from 22,600 to 40,400 M−1 cm−1. Using cyclic voltammetry and UV–visible data, we calculated the optical band gaps, (E0−0) of BZ1‐BZ4 to be 2.09, 2.00...
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Papers by Parag Bhargava