On the Convergence of Quasilinear Viscous Approximations with Degenerate Viscosity

We use Velocity Averaging lemma to show that the almost everywhere limit of quasilinear viscous approximations is the unique entropy solution (in the sense of {\it F. Otto}) of the corresponding scalar conservation laws on a bounded domain in $\mathbb{R}^{d}$, where the viscous term is of the form $\varepsilon\,div\left(B(u^{\varepsilon})\nabla u^{\varepsilon}\right)$ and $B\geq 0$.Comment: 25 pages. Submitted to a Journal. arXiv admin note: text overlap with arXiv:2209.0166

Biochar production though combined solar drying & single chamber pyrolysis

In this study, the challenging management of fibrous organic wastes (FOW) and dewatered municipal sewage sludge (MSS) in urban areas of Asia’s newly industrialised countries is presented with high energy efficiency, negative CO2 balance and biochar generation. This study investigates the feasibility and benefits of a combined treatment approach for both of the substrates, comprising solar drying (SD) and pyrolysis process (PYR). Based on material investigations, a calculation model is developed to project the material and energy flows of this process combination on the example of Chennai, India. Please click Additional Files below to see the full abstract

Biochar from co-pyrolysis of urban organic wastes : Investigation of carbon sink potential using ATR-FTIR and TGA

Urban organic wastes (UOW) strain the infrastructures for solid waste treatment (SWT) in emerging economies. This study investigated biochar gained from three major UOW sources in India—banana peduncles (BP), a fibrous waste, from fruit markets; sewage sludge (SS) from wastewater treatment plants; and anaerobic digestate (AD) from food and market waste processing facilities—in terms of its potential to sequester and become long-term carbon sink in soils. Herein, the chemical properties (using ATR-FTIR) and thermal oxidative stability (using TGA) of biochars derived from these UOW and their three blends were examined. Biochar from SS and AD and the blends were found to possess more ash content, Cl, and alkali and alkaline earth metals (AAEM) than that from BP. The conventional recalcitrance index (R50) could not quantify and compare the stability of these mineral- and ash-rich biochars. Hence, a modified thermal oxidative recalcitrance index (TORi) is proposed. All the biochar from blends prepared at highest treatment temperature of 650 °C shows similar aromaticity. However, biochar from blend of 50% SS, 30%BP, and 20% AD exhibits the highest recalcitrance (TORi = 0.193) to become a long-term carbon sink in soil. More than aromaticity, the influence of Si, Fe, and AAEM on the biochar matrix affects its recalcitrance. Variations in the structural properties and recalcitrance of biochars from blends are attributable to the synergy among their constituents SS, AD, and BP. The determined TORi confirms the potential of biochar from the blends of UOW as a long-term carbon sink. © 2020, The Author(s)

Biochar Synthesis from Mineral- and Ash-Rich Waste Biomass, Part 1: Investigation of Thermal Decomposition Mechanism during Slow Pyrolysis

Synthesizing biochar from mineral- and ash-rich waste biomass (MWB), a by-product of human activities in urban areas, can result in renewable and versatile multi-functional materials, which can also cater to the need of solid waste management. Hybridizing biochar with minerals, silicates, and metals is widely investigated to improve parent functionalities. MWB intrinsically possesses such foreign materials. The pyrolysis of such MWB is kinetically complex and requires detailed investigation. Using TGA-FTIR, this study investigates and compares the kinetics and decomposition mechanism during pyrolysis of three types of MWB: (i) mineral-rich banana peduncle (BP), (ii) ash-rich sewage sludge (SS), and (iii) mineral and ash-rich anaerobic digestate (AD). The results show that the pyrolysis of BP, SS, and AD is exothermic, catalyzed by its mineral content, with heat of pyrolysis 5480, 4066, and 1286 kJ/kg, respectively. The pyrolysis favors char formation kinetics mainly releasing CO2 and H2O. The secondary tar reactions initiate from ≈318 °C (BP), 481 °C (SS), and 376 °C (AD). Moreover, negative apparent activation energies are intrinsic to their kinetics after 313 °C (BP), 448 °C (SS), and 339 °C (AD). The results can support in tailoring and controlling sustainable biochar synthesis from slow pyrolysis of MWB

Post-Kala-azar Dermal Leishmaniasis in Nepal: A Retrospective Cohort Study (2000–2010)

Post-kala-azar dermal leishmaniasis (PKDL) is a skin disorder seen in patients treated for Leishmania donovani visceral leishmaniasis (VL), a neglected tropical disease that is fatal if left untreated. In the Indian subcontinent, PKDL is seen in 5–10% of all past VL cases and is also reported in some without history of VL. As persons with PKDL do not feel sick, the disease has only cosmetic significance for the individual and treatment is rarely sought. However, PKDL lesions harbour parasites and therefore could represent a source of transmission, through the bite of female sand flies. Our study shows that the occurrence of PKDL in patients with past treated VL is low in Nepal compared to neighboring countries. Treatment of the original VL episode with SSG (sodium stibogluconate), inadequate treatment and treatment on ambulatory basis were significantly associated with PKDL. Though SSG has since been replaced by other drugs, counseling and supervision of adherence to the prescribed VL treatment is of vital importance to reduce risk of treatment failure and relapse as well as later development of PKDL. Policy makers should include surveillance and case management of PKDL in the VL elimination program