Densification and microstructure development in spark plasma sintered WC-6 wt% ZrO<SUB>2</SUB> nanocomposites

In this paper, we report the results of a transmission electron microscopy investigation on WC-6 wt% Zr02 nanocomposite, spark plasma sintered at 1300 &#176; C, for varying times of up to 20 min. The primary aim of this work was to understand the evolution of microstructure during such a sintering process. The investigation revealed the presence of nanocrystalline Zr02 particles (30-50 nm) entrapped within submicron WC grains. In addition, relatively coarser Zr02 (60-100 nm) particles were observed to be either attached to WC grain boundaries or located at WC triple grain junctions. The evidence of the presence of a small amount of W2C, supposed to have been formed due to sintering reaction between WC and Zr02, is presented here. Detailed structural investigation indicated that Zr02 in the spark plasma sintered nanocomposite adopted an orthorhombic crystal structure, and the possible reasons for o- Zr02 formation are explained. The increase in kinetics of densification due to the addition of is believed to be caused by the enhanced diffusion kinetics in the presence of nonstoichiometric nanocrystalline Zr02

The use of a blood conservation device to reduce red blood cell transfusion requirements: a before and after study

10.1186/cc8859Critical Care141R

Nutritional risk assessment at admission can predict subsequent muscle loss in critically ill patients

The study was supported with National University Health System Clinician Grant 2013

"The fruits of independence": Satyajit Ray, Indian nationhood and the spectre of empire

Challenging the longstanding consensus that Satyajit Ray's work is largely free of ideological concerns and notable only for its humanistic richness, this article shows with reference to representations of British colonialism and Indian nationhood that Ray's films and stories are marked deeply and consistently by a distinctively Bengali variety of liberalism. Drawn from an ongoing biographical project, it commences with an overview of the nationalist milieu in which Ray grew up and emphasizes the preoccupation with colonialism and nationalism that marked his earliest unfilmed scripts. It then shows with case studies of Kanchanjangha (1962), Charulata (1964), First Class Kamra (First-Class Compartment, 1981), Pratidwandi (The Adversary, 1970), Shatranj ke Khilari (The Chess Players, 1977), Agantuk (The Stranger, 1991) and Robertsoner Ruby (Robertson's Ruby, 1992) how Ray's mature work continued to combine a strongly anti-colonial viewpoint with a shifting perspective on Indian nationhood and an unequivocal commitment to cultural cosmopolitanism. Analysing how Ray articulated his ideological positions through the quintessentially liberal device of complexly staged debates that were apparently free, but in fact closed by the scenarist/director on ideologically specific notes, this article concludes that Ray's reputation as an all-forgiving, ‘everybody-has-his-reasons’ humanist is based on simplistic or even tendentious readings of his work

National survey of outcomes and practices in acute respiratory distress syndrome in Singapore

The authors acknowledge the following as the total funding sources for this study: 1. SICM NICER grant: logistical, non-monetary, support from the Society of Intensive Care Medicine Singapore. This was in the form of Ngee Ann Polytechnic students (8) who collected the data for the study for one month. 2. NMRC (National medical research council) grant for Dr, Matthew Cove (partial support for this study): This was in the shape of salary support for all his research related activity. (NMRC/TA/0015/2013) (MEC)

Fabrication and properties of Oxide Nanocomposites containing uniformly dispersed second phases

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Fabrication and properties of oxide

The present research addresses some of the major problems pertaining to two different types of ceramic nanocomposite; viz. participate reinforced polycrystalline alumina-based nanocomposites and multiwalled carbon nanotube (MWCNT) reinforced aluminoborosilicate glass/ceramic (ABS) nanocomposites. With respect to the former, a novel and economical processing route based upon solid solution-precipitation technique is explored. Dense and homogeneous solid solutions of 10 wt.% Fe2O3 in Al2O3 were produced by pressureless sintering at 1450°C in air. Aging of the solid solutions in a reducing atmosphere at temperatures in the range 1250°C-1550°C for different durations (up to 50 h) resulted in the precipitation of FeAl2eO4 as second phase particles throughout the bulk of the samples. The optimum aging schedules resulted in a final microstructure comprising nanosized (~ 100 nm) intragranular FeAl2eO4 particles, along with coarser micro-sized particles along the matrix grain boundaries and triple point corners. The hybrid nano/micro composites possessed improved fracture toughness (by ~ 40%), flexural strength (by ~ 50%) and abrasive wear resistance (by a factor of ~ 2.5) with respect to monolithic Al2O3. With respect to the ABS - MWCNT nanocomposites, we report here the ability to develop dense nanocomposites, containing uniformly dispersed nanotubes up to a content of 10 wt.%, by an ultrasonication-assisted sol-gel technique followed by hot pressing. The optimised ABS - 10 wt.% MWCNT nanocomposite possessed nearly double the strength, and a fracture toughness improvement of ~ 150% with respect to the unreinforced ABS. The carbon nanotubes have been observed to bridge crack openings of the order of ~ 100 nm which provides the major contribution towards the improvement in fracture toughness. The nanocomposites, showed an electrical percolation threshold of between 2.5 to 5 wt.% MWCNT and possessed significantly higher electrical conductivities (by a factor of 106) with respect to the unreinforced ABS glass/ceramic. Furthermore, 40% improvement in thermal conductivity (~ 1.8 W m-1 K1) over that of unreinforced ABS glass/ceramic was recorded with ABS - 15 wt.% MWCNT nanocomposite.</p

Fabrication and properties of oxide

The present research addresses some of the major problems pertaining to two different types of ceramic nanocomposite; viz. participate reinforced polycrystalline alumina-based nanocomposites and multiwalled carbon nanotube (MWCNT) reinforced aluminoborosilicate glass/ceramic (ABS) nanocomposites. With respect to the former, a novel and economical processing route based upon solid solution-precipitation technique is explored. Dense and homogeneous solid solutions of 10 wt.% Fe2O3 in Al2O3 were produced by pressureless sintering at 1450°C in air. Aging of the solid solutions in a reducing atmosphere at temperatures in the range 1250°C-1550°C for different durations (up to 50 h) resulted in the precipitation of FeAl2eO4 as second phase particles throughout the bulk of the samples. The optimum aging schedules resulted in a final microstructure comprising nanosized (~ 100 nm) intragranular FeAl2eO4 particles, along with coarser micro-sized particles along the matrix grain boundaries and triple point corners. The hybrid nano/micro composites possessed improved fracture toughness (by ~ 40%), flexural strength (by ~ 50%) and abrasive wear resistance (by a factor of ~ 2.5) with respect to monolithic Al2O3. With respect to the ABS - MWCNT nanocomposites, we report here the ability to develop dense nanocomposites, containing uniformly dispersed nanotubes up to a content of 10 wt.%, by an ultrasonication-assisted sol-gel technique followed by hot pressing. The optimised ABS - 10 wt.% MWCNT nanocomposite possessed nearly double the strength, and a fracture toughness improvement of ~ 150% with respect to the unreinforced ABS. The carbon nanotubes have been observed to bridge crack openings of the order of ~ 100 nm which provides the major contribution towards the improvement in fracture toughness. The nanocomposites, showed an electrical percolation threshold of between 2.5 to 5 wt.% MWCNT and possessed significantly higher electrical conductivities (by a factor of 106) with respect to the unreinforced ABS glass/ceramic. Furthermore, 40% improvement in thermal conductivity (~ 1.8 W m-1 K1) over that of unreinforced ABS glass/ceramic was recorded with ABS - 15 wt.% MWCNT nanocomposite