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Wu Y.,National University of Singapore | Balakrishna R.,National University of Singapore | Reddy M.V.,National University of Singapore | Nair A.S.,National University of Singapore | And 3 more authors.
Journal of Alloys and Compounds | Year: 2012

One-dimensional (1D) nickel oxide/ruthenium oxide (NiO/RuO 2)-carbon composite nanofibers (NiRu-C-NFs) were fabricated via electrospinning of a homogenous mixture of polyacrylonitrile (PAN) and Ni/Ru salt precursors at different ratios followed by heat treatments. The 1D nanostructures of the composite material were characterized by field-emission scanning electron microscopy (FE-SEM), powder X-ray diffraction (XRD), Rietveld refinement and Brunauer-Emmett-Teller (BET) surface area measurements. Li-cycling properties were evaluated using cyclic voltammetry and galvanostatic properties. The asymmetric hybrid supercapacitor studies were carried out with activated carbon as a cathode and NiRu-C-NFs composites as anodes in the cycling range, 0.005-3.0 V using 1 M LiPF 6 (EC;DMC) electrolyte. NiRu-C-NFs fabricated from 5 wt% nickel (II) and 15 wt% ruthenium (III) precursors showed a capacitance up to ∼60 F g -1 after 30 cycles. Anodic Li-cycling studies of NiRu-C-NF-0 and NiRu-C-NF-2 composite samples showed a reversible capacity of 230 and 350 m Ahg -1 at current rate of 72 mA g -1 at the end of 40th cycle in the voltage range of 0.005-3.0 V. Electrochemical impedance studies (EIS) on NiRu-C-NFs showed lower impedance value for 15 wt% Ru than the bare sample. © 2011 Elsevier B.V.

Machacova K.,Albert Ludwigs University of Freiburg | Papen H.,Karlsruhe Institute of Technology | Kreuzwieser J.,Albert Ludwigs University of Freiburg | Rennenberg H.,Albert Ludwigs University of Freiburg | Rennenberg H.,Kind Saud University
Plant and Soil | Year: 2013

Background and aims: Nitrous oxide (N2O) and methane (CH4) can be emitted from surfaces of riparian plants. Data on the emission of these greenhouse gases by upland trees are scarce. We quantified CH4 and N2O emissions from stems of Fagus sylvatica, an upland tree, and Alnus glutinosa, a riparian tree. Methods: The gas fluxes were investigated in mesocosms under non-flooded control conditions and during a flooding period using static chamber systems and gas chromatographic analyses. Results: Despite differences in the presence of an aerenchyma system, both tree species emitted N2O and CH4 from the stems. Flooding caused a dramatic transient increase of N2O stem emissions by factors of 740 (A. glutinosa) and even 14,230 (F. sylvatica). Stem emissions of CH4 were low and even deposition was determined (F. sylvatica controls). The results suggest that CH4 was transported mainly through the aerenchyma, whereas N2O transport occurred in the xylem sap. Conclusions: For the first time it has been demonstrated that upland trees such as F. sylvatica clearly significantly emit N2O from their stems despite lacking an aerenchyma. If this result is confirmed in adult trees, upland forests may constitute a new and significant source of atmospheric N2O. © 2012 Springer Science+Business Media B.V.

Abdelnaser O.,Universiti Sains Malaysia | Mahmood A.,Kind Saud University | Read A.D.,Aea Environment And Energy
Journal of Solid Waste Technology and Management | Year: 2011

The motivating and de-motivating factors that affect the effective participation of people of Pulau Pinang in the recycling of their domestic solid wastes were studied. 300 questionnaires were distributed to different areas of Pulau Pinang using a sampling frame that allowed various ethnic groups, different age groups, diverse vocations and a range of residential arrangements and the sexes to be captured - ensuring the sample was representative of the general population of the area. The research adopted a stratified sampling technique, where the Island was divided into several strata and each stratum was administered with questionnaires using a snowball approach. 275 of the questionnaires (91.7%) were completed and returned. Data collected were analyzed by converting Likert scale scores to Relative Importance Index (RII). Results of the survey showed that the majority (61%) of residents of Pulau Pinang did participate in recycling. Most recyclers are Malays, Chinese and other Malaysians, who were either students or workers in the private sector. Recyclers also tended to be those living in condominiums/apartments or terrace houses and the materials recycled were mostly paper or paper products. These groups obtain recycling related information mostly from the television. The recycling activity is generally motivated by personal concerns for the environment and the promotion of good health whereas participation in recycling services/activities is 'de-motivated' by a lack of suitable/local facilities for recycling and the time and effort spent/required in using them.

Zafar Z.U.,Bahauddin Zakariya University | Athar H.,Bahauddin Zakariya University | Ashraf M.,University of Agriculture at Faisalabad | Ashraf M.,Kind Saud University
Pakistan Journal of Botany | Year: 2010

Use of pesticides to eradicate pest attack on cotton crops has increased substantially during the past decade posing a serious threat to environment and human health. Application of nitrogenous fertilizers which modulates plant metabolism might reduce pest and pest-induced viral diseases. Understanding physiological basis of nitrogen nutrition on disease incidence in cotton may help in developing strategies to prevent, avoid, escape and control viral diseases. Thus, responses of two cultivars of cotton (Gossypium hirsutum L.), S-12 (CLCuV-susceptible) and CIM-448 (CLCuV-resistant), to varying concentrations of nitrogen were examined. Plants of both cotton cultivars were grown at varying concentration [224, 114 (control) and 56 mg N L-1] of nitrogen supplied with Hoagland's nutrient solution. The virus resistant cultivar, CIM-448 remained free of all disease symptoms throughout the experiment, whereas in virus susceptible cultivar S-12 leaf curling and vein thickening occurred at all external nitrogen regimes. However, severity of disease symptoms decreased with decreasing external N supply. Growth of both cotton cultivars increased due to increasing external N supply. The CLCuV-resistant cultivar, CIM-448 had significantly greater fresh and dry biomass as compared to the virus susceptible cultivar S-12 at all external nitrogen regimes. Leaf epicuticular wax content was greater in CLCuV-resistant cultivar as compared to that of non-diseased leaves of CLCuV-susceptible cotton cultivar S-12. However, the diseased leaves of CLCuV-susceptible cultivar S-12 had higher epicuticular wax content as compared to those of healthy S-12 and CIM-448. Leaf K+ decreased with decrease in N regimes in both cultivars. However, diseased leaves of S-12 had significantly higher leaf K+ and Ca2+ as compared to those of healthy S-12 and CIM-448. Leaf Mg2+ concentration was higher in CIM-448 as compared to that in diseased or healthy leaves of S-12 at all N levels. Accumulation of N declined with decrease in N levels. However, CIM-448 had higher N content as compared to healthy or diseased leaves of S-12. Leaf P content was inconsistent in two cotton cultivars at different N levels. In conclusion, growth of both cotton cultivars increased with increase in N nutrition in growth medium, which in turn was associated with higher accumulation of N and K accumulation. However, vigorous growth of S-12 cultivar with high N supply enhanced the disease susceptibility due to change in pattern of N and K accumulation at different N levels, whereas the disease resistance of CIM-448 remained unchanged at changing N levels.

Richardson S.,University of Cardiff | Cooper A.,University of Swansea | Alghamdi M.,Kind Saud University | Alghamdi M.,King Khalid University | Altowaijri A.,University of Cardiff
International Journal of Therapy and Rehabilitation | Year: 2012

Background: Observational gait analysis used by clinicians has been shown to have moderate reliability in relation to joint angles. Siliconcoach movement analysis software uses a digital image to determine joint angles. The aim of this study was to compare Siliconcoach software against experienced clinicians in assessing knee hyperextension in patients following stroke. Method: This was an observational comparison study with a convenient sample of 20 ambulant participants with a unilateral stroke videoed during three walks. To determine knee hyperextension and the reliability of Siliconcoach the recordings were assessed by three raters using Siliconcoach and by three experienced clinicians. Findings: The Kappa statistic for intra-observer agreement for knee hyperextension ranged from 0.8 to 1.0 (substantial to almost perfect) and from 0.6 to 0.9 for inter-observer agreement (moderate to almost perfect). Intra-rater and inter-rater ICC scores for Siliconcoach were all >0.75 suggesting very high reliability. Clinicians compared with Siliconcoach ranged from 0.4 to 0.7(fair to substantial). Conclusion: Observational gait analysis appears to be an adequate measurement tool in clinical practice particularly when undertaken by the same experienced therapist. However, Siliconcoach may be a more reliable measure and provides an objective measure of quantifying knee joint angles for both research and clinical practice.

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