Forest carbon stocks and fluxes in physiographic zones of India

<p>Abstract</p> <p>Background</p> <p>Reducing carbon Emissions from Deforestation and Degradation (REDD+) is of central importance to combat climate change. Foremost among the challenges is quantifying nation's carbon emissions from deforestation and degradation, which requires information on forest carbon storage. Here we estimated carbon storage in India's forest biomass for the years 2003, 2005 and 2007 and the net flux caused by deforestation and degradation, between two assessment periods i.e., Assessment Period first (ASP I), 2003-2005 and Assessment Period second (ASP II), 2005-2007.</p> <p>Results</p> <p>The total estimated carbon stock in India's forest biomass varied from 3325 to 3161 Mt during the years 2003 to 2007 respectively. There was a net flux of 372 Mt of CO₂in ASP I and 288 Mt of CO₂in ASP II, with an annual emission of 186 and 114 Mt of CO₂respectively. The carbon stock in India's forest biomass decreased continuously from 2003 onwards, despite slight increase in forest cover. The rate of carbon loss from the forest biomass in ASP II has dropped by 38.27% compared to ASP I.</p> <p>Conclusion</p> <p>With the Copenhagen Accord, India along with other BASIC countries China, Brazil and South Africa is voluntarily going to cut emissions. India will voluntary reduce the emission intensity of its GDP by 20-25% by 2020 in comparison to 2005 level, activities like REDD+ can provide a relatively cost-effective way of offsetting emissions, either by increasing the removals of greenhouse gases from the atmosphere by afforestation programmes, managing forests, or by reducing emissions through deforestation and degradation.</p

Mg-chelatase H subunit affects ABA signaling in stomatal guard cells, but is not an ABA receptor in Arabidopsis thaliana

Mg-chelatase H subunit (CHLH) is a multifunctional protein involved in chlorophyll synthesis, plastid-to-nucleus retrograde signaling, and ABA perception. However, whether CHLH acts as an actual ABA receptor remains controversial. Here we present evidence that CHLH affects ABA signaling in stomatal guard cells but is not itself an ABA receptor. We screened ethyl methanesulfonate-treated Arabidopsis thaliana plants with a focus on stomatal aperture-dependent water loss in detached leaves and isolated a rapid transpiration in detached leaves 1 (rtl1) mutant that we identified as a novel missense mutant of CHLH. The rtl1 and CHLH RNAi plants showed phenotypes in which stomatal movements were insensitive to ABA, while the rtl1 phenotype showed normal sensitivity to ABA with respect to seed germination and root growth. ABA-binding analyses using 3H-labeled ABA revealed that recombinant CHLH did not bind ABA, but recombinant pyrabactin resistance 1, a reliable ABA receptor used as a control, showed specific binding. Moreover, we found that the rtl1 mutant showed ABA-induced stomatal closure when a high concentration of extracellular Ca2+ was present and that a knockout mutant of Mg-chelatase I subunit (chli1) showed the same ABA-insensitive phenotype as rtl1. These results suggest that the Mg-chelatase complex as a whole affects the ABA-signaling pathway for stomatal movements

Design of bio-nanosystems for oral delivery of functional compounds

Nanotechnology has been referred to as one of the most interesting topics in food technology due to the potentialities of its use by food industry. This calls for studying the behavior of nanosystems as carriers of biological and functional compounds aiming at their utilization for delivery, controlled release and protection of such compounds during food processing and oral ingestion. This review highlights the principles of design and production of bio-nanosystems for oral delivery and their behavior within the human gastrointestinal (GI) tract, while providing an insight into the application of reverse engineering approach to the design of those bio-nanosystems. Nanocapsules, nanohydrogels, lipid-based and multilayer nanosystems are discussed (in terms of their main ingredients, production techniques, predominant forces and properties) and some examples of possible food applications are given. Phenomena occurring in in vitro digestion models are presented, mainly using examples related to the utilization of lipid-based nanosystems and their physicochemical behavior throughout the GI tract. Furthermore, it is shown how a reverse engineering approach, through two main steps, can be used to design bio-nanosystems for food applications, and finally a last section is presented to discuss future trends and consumer perception on food nanotechnology.Miguel A. Cerqueira, Ana C. Pinheiro, Helder D. Silva, Philippe E. Ramos, Ana I. Bourbon, Oscar L. Ramos (SFRH/BPD/72753/2010, SFRH/BD/48120/2008, SFRH/BD/81288/2011, SFRH/BD/80800/2011, SFRH/BD/73178/2010 and SFRH/BPD/80766/2011, respectively) are the recipients of a fellowship from the Fundacao para a Ciencia e Tecnologia (FCT, POPH-QREN and FSE Portugal). Maria L. Flores-Lopez thanks Mexican Science and Technology Council (CONACYT, Mexico) for PhD fellowship support (CONACYT Grant number: 215499/310847). The support of EU Cost Actions FA0904 and FA1001 is gratefully acknowledged

High performance PEEK/AlN micro- and nanocomposites for tribological applications

The tribological properties of poly(etheretherketone) (PEEK)/aluminum nitride (AlN) composites reinforced with micro- and nano-AlN particles were evaluated under dry sliding conditions. The wear resistance of pure PEEK is 10-fold higher than mild steel. It was further improved by 2-fold at 20 wt % micro-AlN and by more than 4-fold at 30 wt % nano-AlN composite compared with pure PEEK. The improvement in wear resistance was attributed to a thin and coherent transfer film. However, it was deteriorated on further increasing micro-AlN. The coefficient of friction of the composites was increased. Scanning electron microscopy and optical microscopy of worn surfaces and transfer films have been explained in detail. (c) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 201

High performance polymer composites on PEEK reinforced with aluminum oxide

A study on high performance poly(ether-ether-ketone) (PEEK) composites prepared by incorporating aluminum oxide (Al2O3), 0 to 50 wt % by hot compaction at 15 MPa and 350 degrees C was described. Density, thermogravimetric analysis/differential scanning calorimetry, and scanning electron microscopy (SEM) were employed to evaluate their density, thermal stability, crystallinity, and morphology. Experimental density was found higher than theoretical density, which indicates that composite samples are sound. It was found that the addition of micron sized (< 15 mu m) Al2O3 increased the peak crystallization temperature by 12 degrees C when compared with neat PEEK with insignificant increase in melting temperature. Half-time of crystallization is reduced from 2.05 min for the neat PEEK to 1.08 min for PEEK incorporated with 30 wt % Al2O3 because of the strong nucleation effect of Al2O3. The thermal stability of composites in air atmosphere was increased by 26 degrees C. However, thermal stability in nitrogen atmosphere decreases at lower concentration of Al2O3 but increases above 20 wt % of Al2O3. Uniform dispersion of Al2O3 particles was observed in PEEK polymer matrix by SEM. (c) 2006

Role of Interface on Dynamic Modulus of High-Performance Poly(etheretherketone)/Ceramic Composites

High-performance printed circuit board or electronic packaging substrate with low warping particularly at high frequency is the key demand of manufacturers. In the present work, poly(etheretherketone) (PEEK) matrix composites reinforced with untreated micron size aluminum nitride (AlN) and alumina (Al(2)O(3)) particles have been studied for dynamic modulus in the temperature range varying from 30 to 250 degrees C. At 48 vol % particles, the room temperature modulus of the PEEK/AlN composites increased by approximately fivefold (similar to 23 GPa), whereas it increased by twofold for PEEK/Al(2)O(3) composite. The reinforcing efficiency is more pronounced at higher temperatures. The significant improvement in modulus was attributed to the better adhesion between the matrix and the AlN particles. Scanning electron microscope (SEM) and Kubat parameter showed that the poor adhesion between the matrix and the Al(2)O(3) particles resulted in comparatively smaller increase in modulus of PEEK/Al(2)O(3), despite higher intrinsic modulus of Al(2)O(3) than that of AlN. SEM showed almost uniform distribution of particles in the matrix. The experimental data were correlated with several theoretical models. The Halpin-Tsai model with xi (xi) is equal to four correlates well up to 48 vol % AlN composites while xi is equal to two correlates only up to 18 vol % Al(2)O(3) composites. Guth-Smallwood model also correlates well up to 28 vol % AlN and 18 vol % Al(2)O(3)-filled composites. Thereafter, data deviated from it due to the particles tendency to aggregate formation. (c) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 436-444, 201

Microhardness of PEEK/ceramic micro- and nanocomposites: correlation with Halpin–Tsai model

Microhardness of high performance PEEK matrix composites reinforced with micro- and nanosize ceramic particles of aluminum nitride and alumina was evaluated with Vickers hardness tester. The microhardness of composites increases with increasing ceramic particle loading. The microhardness of PEEK/AlN composites is higher than that of PEEK/Al2O3 composites. For a given volume fraction, the improvement in microhardness of nanocomposites is higher than that of microcomposites. For the first time, the Halpin–Tsai equation was applied to correlate the microhardness. It was found that the adjustable parameter, i.e. ξ, is different for both particles. The value of ξ is higher for nanocomposites compared to microcomposites© Elsevie

Thermal, Mechanical, and Dielectric Properties of High Performance PEEK/AIN Nanocomposites

The mechanical, thermal, and dielectric properties of novel high performance poly(ether-ether-ketone) (PEEK)/AIN nanocomposites were discussed. The stiffness of the nanocomposites was significantly improved in the glassy state as well as rubbery state. The coefficient of thermal expansion (CTE) of the nanocomposites was found substantially lower than that of pure PEEK. The glass transition temperature and melting temperature of the nanocomposites were increased significantly. The thermal stability and dielectric constant of the nanocomposites were increased slightly with AIN content. The significant improvement in the properties of the nanocomposites was attributed to the good adhesion between the AIN nanoparticles and the polymer matrix. The fabricated nanocomposite is very promising for use in electronics packaging substrate as an alternative substrate owing to its good thermal, mechanical and dielectric properties

Effect of aluminum nitride on thermomechanical properties of high performance PEEK

High performance polymer matrix composites based on poly(ether–ether–ketone) (PEEK) as matrix and aluminum nitride particle (AlNp) as filler were prepared. The effect of AlNp on the storage modulus, loss modulus, mechanical loss factor, and glass transition were investigated. The AlNp reinforcement is more pronounced above glass transition temperature (Tg). Composite containing 70 wt.% AlNp exhibit about 100% increase in storage modulus at 50 °C and about 500% increase at 250 °C, and 19 °C increase in glass transition temperature as compared to pure PEEK. Peak height of tan δ for composites was decreased to one sixth of the pure PEEK. It is probably due to improved crystallinity of PEEK and strong interaction between the AlNp and PEEK matrix. SEM reveals excellent distribution of AlNp in PEEK matrix and good interaction between AlNp and PEEK matrix.© Elsevie

Study on Microhardness, Dynamic Mechanical, and Tribological Properties of PEEK/Al2O3 Composites

The wear and friction properties of poly (ether-ether-ketone) (PEEK) reinforced with 0-33 vol % (60 wt %) micron size Al2O3 composites were evaluated at a sliding speed of 1.0 m/s and nominal pressure from 0.5 to 1.25 MPa under dry sliding conditions using a pin-on-disk wear tester. The wear resistance of the pure PEEK is 10-fold higher than that of mild steel under the similar test condition. It is improved to 18-fold as compared with mild steel at 3.5 vol % Al2O3 content. The improvement in wear properties may be attributed to the thin, tenacious, and coherent transfer film formed between the steel countersur-face and composite pin. However, the wear resistance of PEEK containing above 3.5 vol % Al2O3 was deteriorated, despite their higher hardness and stiffness as compared with that of composites containing lower Al2O3 content. This is attributed to the formation of thick and noncoherent transfer film, which does not prevent the wear of the composites from hard asperities of countersurface. Moreover, hard Al2O3 particles present in transfer film act as third body wear mechanism. The coefficient of friction of the composites is higher than that of pure PEEK. SEM and optical microscopy have shown that wear of pure PEEK Occurs by the mechanism of adhesion mainly whereas of PEEK composites by microploughing and abrasion. (C) 2008 . J Appl Polym Sci 110: 3379-3387, 200