Advanced Materials Research Vol. 856

Abstract: LiCrO₂ is a triangular lattice antiferromagnetic compound exhibiting geometrically frustrated two dimensional arrangement of Cr ions with T_N = 62 K at which an isostructural transition occurs. We show, using temperature dependent high energy synchrotron X-ray diffraction studies, that upon a nominal 1% Cu doping at the Li site, there are large changes in structural parameters and the (coupled) magnetic and dielectric properties.

Abstract: Abstract. In this research experimental investigation of the influence of copper introduction on some relevant parameters in As-S-Se amorphous thin films is performed. Copper is introduced into As₂(S_0.5Se_0.5)₃ amorphous thin film in concentration of 3 at.%. Samples of As₂(S_0.5Se_0.5)₃ and Cu₃(As₂(S_0.5Se_0.5)₃)₉₇ amorphous thin films are prepared by the vacuum thermal evaporation technique from previously synthesized bulk samples. Envelope method is applied for the determination of the optical constants, using the transmission and reflection spectra. The dispersion of the refractive index is discussed in terms of the single oscillator model proposed by Wemple–DiDomenico. Values of absorption coefficients in the high absorption region are discussed according to Tauc's law.Instrumented indentation testing is performed, using the Berkovich geometry indenter, for obtaining the value of nano-hardness.All the determined parameters have shown the increase with introduction of copper into amorphous thin film.

Abstract: India has the highest incidences of prostate cancer in the world. The elevated occurrence of prostate cancer in India has long been linked with the lifestyle and family history. The survival rate of prostate cancer is 6080% when detected during its early stages; however, this number drops to 3040% when the cancer is diagnosed during the advanced stages. A sol-gel based nanobio sensor can be developed for the detection of prostate cancer from blood using Prostate Specific Antigen (PSA), a prostate cancer marker. Solgel-derived materials can be exploited for the manufacturing of various optoelectronic devices, including sensors optodes and their protective layers, as well as other kinds of coatings. One of the objectives of present study is to explicate the changes in the internal environment of the sol-gel.

Abstract: The aim of this paper is to study the performance of infused nanoSiO₂ gel (NSG) on the developed alkaline activated binary blending of ground blast furnace slag (GBFS) and ultrafine palm oil fuel ash (UPOFA) based mortar (AAGU) using the constant mass of combined activators (10 M NaOH_aq+Na₂SiO_3aq (Ms = SiO₂/Na₂O=3.3)). The methods include using the 3-day compressive strength results and microstructural characterization (SEM+EDX and FTIR). The finding revealed that the compressive strength of the mortar increased with NSG and the maximum strength achieved was 57.3 MPa signifying 21% strength gain compared to NSG-free sample. The NSG also played the role of microcracks and pore fillings, increased the product homogeneity and reduced its amorphousity due to silicate re-organization but has no effects on Si-Al substitution.

Abstract: Nano kaolin is product from kaolin also known as white clay. Kaolin was established as supplementary cementitious materials in concrete. The inclusion of kaolin in concrete enhances strength and durability properties and prolongs concrete life span. In this research, nanokaolin will be develop by using sol gel technique by that involves high energy milling. The process of milling been influenced by time of milling, ball and jar type. Ceramic type Zirconia (Zi) is been used as jar and ball type in this process. Time of milling was set from four (4) hours and one (1) days. Sample will be analyse by using particle size analyser to see the particle size and surface area of kaolin. From the result shows the optimum milling period for nanokaolin is one day base on particle size compare to 4 hours. Furthermore, one day milling produces a massive increment of surface area compare to others. In conclusion, one day can be considered as the optimum cycle time in the production of nano kaolin.

Abstract: This study presents a method for the fabrication of ultrafine polymeric nanofibers utilizing centrifugal and electrostatic forces simultaneously. To reduce the diameter and variability of nanofibers produced from solid state polymerized PA66 (SSP PA66), a unique electro-centrifuge spinning device was designed using rotating nozzle and collector, whereas the fabrication process (spinning head) was skillfully sealed from ambient airflow. An electric field is applied between the nozzle containing the polymer solution and cylindrical collector. Due to centrifugal force, polymer solution is ejected from the nozzle tip and extended by centrifugal force as well as electrical force. The diameters of nanofibers were controlled by adjusting the selected affecting parameters such as solution concentration, rotational speed of spinning head, syringe content as well as applied voltage. With this new technique, nanofibers were electrospun from SSP PA66 solutions. Field emission scanning electron microscope (FESEM) results demonstrated that ASCES has the unique ability to produce high quality ultrafine nanofibers from SSP PA66 polymer. Well control of parameters was tended to produce the thinnest fibers with mean diameter of 63 nm.

Abstract: Synchrotron based X-ray diffraction (XRD) and X-ray reflectivity (XRR) were used to study the structural and magnetic properties of ion beam sputtered Fe/Al multilayer sample (MLS) as a function of annealing temperature. The structural studies show substantial intermixing between the layers which results in multilayer of complicated structures i.e. formation of thin intermixed FeAl layer at the interface during deposition, the nucleation and precipitation of disordered FeAl layer, and its subsequent growth to Fe₃Al at higher temperature. The results were also supported by TEM measurements. Magnetization decreases with increase in temperature and Curie temperature (T_c) is found to be much less than that of bulk bcc Fe.

Abstract: We report a novel approach of designing ordered arrangement of disorder on the extended structures of graphene. We prepared single phase nanoparticles of Co₈₀Ni₂₀ alloy embedded in Reduced Graphene Oxide (RGO). Co₈₀Ni₂₀ shows a large moment and a soft ferromagnetic character like permalloy at room temperature. Temperature dependence of permittivity shows a behavior quite contrary to usual ceramic materials showing an increase with decreasing temperature, exhibiting a maximum. A very large magnitude of permittivity ~ 5000 is observed, which is possibly related to an interesting Maxwell-Wagner type effect arising from the charge localization in the graphene sheets. For a deeper insight of the mechanism, correlations with other phenomena are studied through magnetization, dc resistivity, I-V etc. investigations. Temperature dependent magnetization indicates toward strong ferromagnetic interaction and MH loop shows low coercivity ferromagnetic interaction at 4 K and even at room temperature.

Abstract: Nanoscale zinc substituted hydroxyapatite has been synthesized by solgel technique at 70 C using an aqueous solution of calcium nitrate tetrahydrate (CNT), zinc nitrate tetrahydrate (ZNT) and potassium dihydrogen phosphate (KDP) as starting materials with or without a capping agent, triethanolamine (TEA). The synthesized nanopowders were calcined at two temperatures 800 C and 1000 C for 1 hr. The morphology and size of nanopowders were characterized by transmission electron microscopy. The BET surface area was evaluated from N₂ adsorption isotherms. Structural analysis and thermal behavior were investigated by means of Fourier transform infrared spectroscopy, x-ray diffraction and thermogravimetry. The results of TEM confirmed that TEA is effective in reducing average crystallite size from 15 nm in case of zinc substituted hydroxyapatite without TEA (ZnHA) to 9 nm in case of zinc substituted hydroxyapatite with TEA (ZnHA-TEA). FTIR spectra showed the presence of weaker HPO₄ bands and stronger O-H bands in case of ZnHA as compared to ZnHA-TEA, which indicated that the formation of the latter is delayed due to TEA assistance. TGA study revealed that ZnHA is thermally more stable as compared to ZnHA-TEA. These results show that the introduction of capping agent effectively restricts the particle growth during precipitation as well as on calcination.

Abstract: In this study the castor oil based polyurethane (PU) nanocomposites were prepared by dispersing the cellulose nanocrystallites (CNC) isolated from cotton linters. CNC was dispersed in PU matrix using ultrasonicator coupled with high shear homogenizer. The filler loading was varied from 0-10% of the total weight of the mixture. The PU/CNC nanocomposites were characterized by SEM, XRD, FTIR, mechanical and barrier properties. SEM confirmed homogeneous dispersion of CNCs in polyurethane matrix with small agglomerates at certain places. Improvement in mechanical properties was observed as compared to neat PU. Diffusivity and permeability of the nanocomposites was reduced at higher loadings of CNC.