75 research outputs found
Tracking Climate Change Vulnerability at Municipal Level in Rural Haiti Using Open Data
In least developed tropical countries, vulnerability to climate change (CC) at local scale follows an indicator-based approach and uses information gathered mainly through household surveys or focus groups. Conceived in this way, the vulnerability assessment is rarely repeatable in time, cannot be compared with those carried out in other contexts and usually has low spatial coverage. The growing availability of open source information at municipal level, routinely col-lected, now allows us to switch to vulnerability tracking (continuous, low cost, consistent with global monitoring systems). The aim of this chapter is to propose and verify the applicability of a VICC-Vulnerability Index to Climate Change on a municipal scale for Haiti. The chapter identifies open source information on na-tional, departmental and municipal scale, selects the information on a municipal scale on the basis of quality, identifies the indicators, evaluates the robustness of the index and measures it. The index consists of 10 indicators created using infor-mation relating to monthly precipitations, population density, flood prone areas, crop deficit, farmers for self-consumption, rural accessibility, local plans for CC adaptation, irrigated agriculture and cholera incidence. This information is gath-ered for the 125 mainly rural municipalities of Haiti. The description and discus-sion of the results in followed by suggestions to improve the index aimed at do-nors, local authorities and users
Aging Characteristics of Stationary Lithium-Ion Battery Systems with Serial and Parallel Cell Configurations
The significant market growth of stationary electrical energy storage systems both for private and commercial applications has raised the question of battery lifetime under practical operation conditions. Here, we present a study of two 8 kWh lithium-ion battery (LIB) systems, each equipped with 14 lithium iron phosphate/graphite (LFP) single cells in different cell configurations. One system was based on a standard configuration with cells connected in series, including a cell-balancing system and a 48 V inverter. The other system featured a novel configuration of two stacks with a parallel connection of seven cells each, no cell-balancing system, and a 4 V inverter. The two systems were operated as part of a microgrid both in continuous cycling mode between 30% and 100% state of charge, and in solar-storage mode with day–night cycling. The aging characteristics in terms of capacity loss and internal resistance change in the cells were determined by disassembling the systems for regular checkups and characterizing the individual cells under well-defined laboratory conditions. As a main result, the two systems showed cell-averaged capacity losses of 18.6% and 21.4% for the serial and parallel configurations, respectively, after 2.5 years of operation with 810 (serial operation) and 881 (parallel operation) cumulated equivalent full cycles. This is significantly higher than the aging of a reference single cell cycled under laboratory conditions at 20 °C, which showed a capacity loss of only 10% after 1000 continuous full cycles
Preparation and characterization of transparent PMMA-cellulose-based nanocomposites
Nanocomposites of polymethylmethacrylate (PMMA) and cellulose were made
by a solution casting method using acetone as the solvent. The nanoflber
networks were prepared using three different types of cellulose
nanoflbers: (i) nanofibrillated cellulose (NFC), (ii) cellulose
nanocrystals (CNC) and (iii) bacterial cellulose from nata de coca
(NDC). The loading of cellulose nanoflbrils in the PMMA varied between
0.25 and 0.5 wt\%. The mechanical properties of the composites were
evaluated using a dynamic mechanical thermal analyzer (DMTA). The
flexural modulus of the nanocomposites reinforced with NDC at the 0.5
wt\% loading level increased 23\% compared to that of pure PMMA. The NFC
composite also exhibited a slightly increased flexural strength around
60 MPa while PMMA had a flexural strength of 57 MPa. The addition of NDC
increased the storage modulus (11\%) compared to neat PMMA at room
temperature while the storage modulus of PPMA/CNC nanocomposite
containing 0.25 and 0.5 wt\% cellulose increased about 46\% and 260\% to
that of the pure PMMA at the glass transition temperature, respectively.
Thermogravimetric analysis (TGA) indicated that there was no significant
change in thermal stability of the composites. The UV-vis transmittance
of the CNF nanocomposites decreased by 9\% and 27\% with the addition of
0.25 wt\% CNC and NDC, respectively. This work is intended to spur
research and development activity for application of CNF reinforced PMMA
nanocomposites in applications such as: packaging, flexible screens,
optically transparent films and light-weight transparent materials for
ballistic protection. (C) 2015 Elsevier Ltd. All rights reserved
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