1 diacetate Under Solvent free Condition Shelke

Siliceous mesoporous materials with pores of ordered 2-D hexagonal structure were successfully prepared without hydrothermal treatment from condensation-polymerization of various concentration of quaternary ammonium salt as structure directing agents and silica precursor from the supernatant of coal fly ash (CFA) in the presence of catalyst. The synthesized materials had high surface area of ca. 740 m2 g-1 and pore volume of ca. 0.42 mL g-1. The synthesized material exhibited a narrow size pore distribution and the mean pore diameter as measured by Dollimore-Heal method was about 2.3 nm. The formation of ammonium salt that act as precipitant during the synthesis enable the hydrolysis and co-condensation of the sodium silicate at room temperature.

http://ac.els-cdn.com/S0254058406001957/1-s2.0-S0254058406001957-main.pdf?_tid=94fbfb08-e777-11e2-8c2f-00000aacb361&acdnat=1373251336_eadd3997df60cb3e1b7112b8859a6a6b

The effect of cold isostatic pressing (CIP) on the sinterability of a laboratory synthesized hydroxyapatite (HA) powder was investigated. The starting powder was initially uniaxially diepressed at about 6 kN force to form disk and rectangular green compacts. Two batches of green samples were prepared, i.e. one batch was in the as-compacted state (Un-CIP) and another batch samples was subjected to cold isostatic press at 200 MPa (CIP). The latter samples exhibited a linear shrinkage of ∼16% prior to sintering. All the samples were sintered in air at temperatures ranging from 700°C to 1400°C. The densification behaviour of HA was evaluated in terms of linear shrinkage, phase stability, bulk density, Vickers hardness and Young's modulus. The results revealed that green samples subjected to cold isostatic pressing exhibited better sinterability and possessed excellent mechanical properties. This effect is more pronounced particularly for the low temperature sintering regime i.e. ≤ 1100°C.

http://www.worldscientific.com/doi/abs/10.4015/s101623720400027x

There are several possible methods by which amine groups can be grafted on the surface of activated carbon (AC) to improve their capacity for CO 2 adsorption. Ethylenediamine and diethylenetriamine were selected as amino compounds for anchoring on the surface of an oxidized AC. Oxidation of AC was carried out by concentrated nitric acid. For each amino compound, two "in-solvent" and "solventfree" methods with a number of grafting times were studied. Nitrogen adsorption-desorption at 77 K and proximate and ultimate analysis were used to determine physical and chemical characteristics of the samples. Temperature-programmed (TP) CO 2 adsorption test from 30°C to 120°C were performed to investigate the effect of modification on CO 2 capture. The modification clearly had a negative effect on the textural characteristics of the samples, so the samples showed a less CO 2 uptake at lower temperatures. However, the decrease of capture capacity with increasing temperature is to somewhat softer for amine-grafted samples, so that they have a capacity comparable to the parent sample or even more than that at elevated temperatures. This property may give the new adsorbents this opportunity to be used at flue gas temperature with a higher efficiency. CO 2 capture capacity per unit surface area of all the amine-modified samples, however, was significantly improved, compared to the parent sample presenting a great influence of amino groups on the CO 2 capture capacity. Moreover, the used amine compounds and grafting methods were compared in terms of adsorbent characteristics and CO 2 uptake curves. Cyclic adsorption-desorption tests showed a satisfactory regeneration for the modified samples. © Springer Science+Business Media B.V. 2011.

http://link.springer.com/article/10.1007/s11270-011-0905-7

Bu patent PVA, PEG, PPG gibi polimer malzemeyi ve tercihan borik asit vb bir bor bileşiği belirli oranlarda karıştırıp reaksiyon ürünü hibrit polimeri 400-700 oC kalsinasyon ve 1000-1600 oC sinterleme işlemine tabi tutarak bor karbür üretim yöntemi ile ilgilidir. Bu yöntemin en büyük özelliği ısıl işlem sırasında isteğe bağlı olarak mikro dalga fırın kullanarak enerjiden ve zamandan büyük tasarruf edilmesini sağlamasıdır. Ayrıca bu yöntemle kalsinasyon sonrası öğütme işleminden sonra pelet aşamasında sinterlenecek malzemeye elementel bor yada borik asit katarak bor karbürün borca daha zengin olması veya aluminyum yada mağnezyum katarak değişik bor karbür alaşımlarının hazırlanması mümkün olabilmektedir.

A new framework type LixNi2(MoO4) 3 [0 ≤ x ≤ 4] polyanion compound was synthesized via a glycine-nitrate soft-combustion process at low temperature. The annealed powders were characterized by XRD to confirm the phase formation of the stoichiometric product, Ni2(MoO4)3 in its non-lithiated state. The morphology of the annealed product was found to be composed of soft agglomerates embedded by ultrafine spherical grains. Electrochemical redox properties of the synthesized product were confirmed by employing the new material as a cathode in lithium-containing test cells in an aprotic electrolyte environment (1 M LiPF6 in EC+DMC). Slow scan cyclic voltammetry (SSCV) confirmed the redox behavior corresponding to the reduction/oxidation of the transition metals, Ni and Mo between the potential window of 3.5-1.5 V. The lithium insertion/extraction process was confirmed by galvanostatic measurements on the test cells and they exhibited well discernible discharge/charge profiles with a reversible capacity of 170 mAh/g over the potential window of 3.5-1.5 V after the first charge/discharge cycle. Nevertheless, the discharge capacity was found to deteriorate slowly upon repeated cycling, which might presumably be due to disproportion reaction of the host structure beyond the extent of insertion of two lithium ions.

http://www.sciencedirect.com/science/article/pii/S0022072804001779

The objective of this work is to utilize a low-grade synthetic rutile to produce high-grade titania nanoparticles. Due to the nature of the precursor, the hydrothermal method needs modification in order to accommodate the precursors and chemical reagents. The product will be characterized with the XRD (crystallite size and crystallinity), EDXRF (chemical composition), SEM (Morphology), N2 adsorption-desorption (Surface Area) and UV-Vis-NIR. Results revealed a crystallite size of less than 20 nm, a surface area of 186.8 m 2/g, a morphology that is a combination of agglomeration and particles, and an optical band gap of 3.23 eV. It is concluded that synthetic rutile is a viable precursor to produce high quality titania nanoparticles.

http://www.scientific.net/JNanoR.21.71

"Mesoporous silica is an important material which has various industrial applications. Currently, it is produced from precursors that are costly. In this paper, the successful preparation of siliceous mesoporous materials MCM-41 with pores of ordered 2-dimensional hexagonal structure by condensation-polymerization using quaternary ammonium salt as structure directing agent and supernatant of the coal fly ash (CIA) as silica precursor is described. The synthesized materials had high surface area of 732 m(2)/g and median pore diameter of 2.5 nm. X-ray diffraction analyses revealed that fusion processes are important in extracting silica from quartz in CFA. SEM images of fused CIA revealed two different morphologies of agglomerated spheres attributable to the fused CFA and distorted octahedral grains to the faujasite phase in comparison to the cenospheres morphology of the as-received CFA. MCM-41 was also produced from pure silica source for comparison. The results obtained in the present work demonstrate the feasibility of employing coal fly ash as a potential source of silica to produce MCM-41 mesoporous materials.

http://ac.els-cdn.com/S0924013606008909/1-s2.0-S0924013606008909-main.pdf?_tid=99ca21a0-e777-11e2-afbb-00000aab0f02&acdnat=1373251344_48cf81e6f8a3f55591ed0bea6c814b7a

In this work, castor oil was blended with palm and jatropha oils to improve the yield of solvent-free enzymatic methanolysis reaction. Transesterification reactions were carried out with stoichiometric ratio of methanol to oil and using lipozyme TL IM as catalyst at 45 °C and 200 rpm for 24 h. By adding only 10% castor oil to the reaction medium a surge in the yield of methanolysis of jatropha oil was observed (i.e. from 21.9% to 65.5%). Increasing the amount of castor oil to 20% raised the yield of methanolysis of jatropha oil to 78.3%. Blending 50% castor oil with palm oil increased the yield of enzymatic methanolysis from 11.9% to 76.2%. Mixing castor oil with jatropha and palm oils improved the yield of solvent free single-step methanolysis reaction to the higher amounts than the maximum theoretical yield of lipozyme TL IM (i.e. 67%). © 2012 Elsevier Ltd.

http://ac.els-cdn.com/S0306261912008914/1-s2.0-S0306261912008914-main.pdf?_tid=5c9e2134-025e-11e4-bf45-00000aacb362&acdnat=1404356683_95875bbf37586ed96f2110583ae53ea9 
http://www.sciencedirect.com/science/article/pii/S0306261912008914

The effect of sintering temperature on the sinterability of synthesized nanocrystalline hydroxyapatite (HA) was investigated. The starting powder was synthesized via a novel wet chemical route. HA green compacts were prepared and sintered in atmospheric condition at various temperatures ranging from 900-1300 °C. The results revealed that the thermal stability of HA phase was not disrupted throughout the sintering regime employed. In general, the results showed that above 98% of theoretical density coupled with hardness of 7.21 GPa, fracture toughness of 1.17 MPa m 1/2 and Young's modulus of above 110 GPa were obtained for HA sintered at temperature as low as 1050 °C. Although the Young's modulus increased with increasing bulk density, the hardness and fracture toughness of the sintered material started to decline when the temperature was increased beyond 1000-1050 °C despite exhibiting high densities >98% of theoretical value. The occurrence of this phenomenon is believed to be associated with a thermal-activated grain growth process.

www.sciencedirect.com/science/article/pii/S1468699606002324

One-dimensional CuO nanocrystals with spindly structure were successfully synthesized using pulsed wire explosion technique in deionized water. By modulating the exploding medium temperature spherical Cu nanoparticles and one-dimensional CuO nanocrystals can be selectively synthesized. At low temperature (1 C) the particle growth is governed by Ostwald ripening resulting in formation of equidimensional crystals (spherical). As the exploding temperature increases (60 C), oriented aggregation in a preferential direction resulted in unique spindly nanostructure. A possible crystal growth mechanism for these nanostructures with various morphologies at different exploding temperature is proposed. Particle growth by Ostwald ripening or orientated aggregation is highly dependent on exploding medium temperature. This technique uses pulsed power, hence the energy consumption is low and it does not produce any process byproducts. This study will provide a mean by which a most energy efficient and eco-friendly synthesis of one-dimensional CuO nanocrystals can be realized.

http://link.springer.com/content/pdf/10.1007%2Fs11051-012-1410-7.pdf

A new framework type LixNi2(MoO4) 3 [0 ≤ x ≤ 4] polyanion compound was synthesized via a glycine-nitrate soft-combustion process at low temperature. The annealed powders were characterized by XRD to confirm the phase formation of the stoichiometric product, Ni2(MoO4)3 in its non-lithiated state. The morphology of the annealed product was found to be composed of soft agglomerates embedded by ultrafine spherical grains. Electrochemical redox properties of the synthesized product were confirmed by employing the new material as a cathode in lithium-containing test cells in an aprotic electrolyte environment (1 M LiPF6 in EC+DMC). Slow scan cyclic voltammetry (SSCV) confirmed the redox behavior corresponding to the reduction/oxidation of the transition metals, Ni and Mo between the potential window of 3.5-1.5 V. The lithium insertion/extraction process was confirmed by galvanostatic measurements on the test cells and they exhibited well discernible discharge/charge profiles with a reversible capacity of 170 mAh/g over the potential window of 3.5-1.5 V after the first charge/discharge cycle. Nevertheless, the discharge capacity was found to deteriorate slowly upon repeated cycling, which might presumably be due to disproportion reaction of the host structure beyond the extent of insertion of two lithium ions.

http://www.sciencedirect.com/science/article/pii/S0022072804001779