Altitudinal variation in soil organic carbon stock in coniferous subtropical and broadleaf temperate forests in Garhwal Himalaya

<p>Abstract</p> <p>Background</p> <p>The Himalayan zones, with dense forest vegetation, cover a fifth part of India and store a third part of the country reserves of soil organic carbon (SOC). However, the details of altitudinal distribution of these carbon stocks, which are vulnerable to forest management and climate change impacts, are not well known.</p> <p>Results</p> <p>This article reports the results of measuring the stocks of SOC along altitudinal gradients. The study was carried out in the coniferous subtropical and broadleaf temperate forests of Garhwal Himalaya. The stocks of SOC were found to be decreasing with altitude: from 185.6 to 160.8 t C ha^-1and from 141.6 to 124.8 t C ha^-1in temperature (<it>Quercus leucotrichophora</it>) and subtropical (<it>Pinus roxburghii</it>) forests, respectively.</p> <p>Conclusion</p> <p>The results of this study lead to conclusion that the ability of soil to stabilize soil organic matter depends negatively on altitude and call for comprehensive theoretical explanation</p

Hot-pressed Mn-doped Pb((Zr_0.3Ti_0.7)_0.99Mn_0.01)_O3/polystyrene composites with improved dielectric and energy storage performance

\ua9 2024 Elsevier LtdPolymer composite films are superb dielectrics with high energy storage performance. Accordingly, herein we fabricated thick dumbbell-shaped 0–3 composites by incorporating Pb((Zr0.3Ti0.7)0.99Mn0.01)O3 (PMZT) as filler (0 –20% by weight) into a polystyrene (PS) matrix, using a two-step, solvent-free method involving melt mixing and subsequent hot pressing. The effects of processing parameters, acceptor doping in the filler, and filler content on the thermal, dielectric, and energy storage properties of the composites were investigated. IR spectroscopy and X-ray diffraction studies confirm the successful integration of the perovskite PMZT ceramic into the PS matrix. Notably, the composite morphology displayed a uniform distribution of filler particles, devoid of voids or agglomerates, indicating effective filler reinforcement. Mn ions acting as acceptor dopants in the ceramic filler, enhance the dielectric constant of the PMZT/PS composites while significantly minimizing the dielectric loss. The hot-pressing method promotes the alignment of dipoles of the filler particles within the composites, leading to stronger polarization and enhanced overall dielectric and ferroelectric response. Remarkably, the 20 wt% PMZT/PS composite exhibits an increased maximum polarization of 0.42 \ub5C/cm2 and an 83% energy storage efficiency, making it a promising candidate for energy storage application

Tailoring microstructure and physical properties of poly(vinylidene fluoride–hexafluoropropylene) porous films

This paper presents a systematic study for the production of poly(vinylidene fluoride-hexafluoropropylene), P(VDF-HFP), porous films using solvent evaporation (SE) and non-solvent induced phase separation (NIPS) techniques. Parameters such as volume fraction of the copolymer solution, film thickness, time exposure to air, non-solvent and temperature of the coagulation bath were investigated on the morphology, crystallization and mechanical properties of the samples. Films with different porous morphologies including homogeneous pore sizes, macrovoids and spherulites were obtained depending on the processing conditions, which in turn affect the wettability and mechanical properties of the material. Knowing that the phase content of the films also depends on the processing conditions, this paper shows that P(VDF-HFP) films with tailored porous morphology, electroactive phase content, hydrophobicity, cristallinity and mechanical properties can be achieved for a specific application using the adequate SE and NIPS techniques conditions.This work was supported by FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PEST-C/FIS/UI607/2013 and PEST-C/ QUI/UIO686/2013 and the project Matepro –Optimizing Materials and Processes”, ref. NORTE-07-0124-FEDER 000037”, co-funded by the “Programa Operacional Regional do Norte” (ON.2 – O Novo Norte), under the “Quadro de Referência Estratégico Nacional” (QREN), through the “Fundo Europeu de Desenvolvimento Regional” (FEDER). The authors also thank FCT for financial support under project PTDC/CTM-NAN/112574/2009. V.F.C. thanks the FCT for the SFRH/BPD/98109/2013 grants