Facile Room-Temperature Electrodeposition of Rare Earth Metals in a Fluorine-Free Task-Specific Electrolyte

Electrochemical deposition of rare earth metals at room temperature has attracted increasing interest due to its advantage in energy efficiency over traditional hydrometallurgical and pyrometallurgical processes. Recent progress has been made with fluorinated electrolyte systems; however, the formation of an electrode-passivating fluoride layer by electrolyte decomposition is often overlooked. Such a passivation layer causes significant and rapid decay of the deposition current and significantly hinders practical application. To address this issue, we demonstrate a fluorine (F)-free task-specific electrolyte utilizing the borohydride anion for the efficient electrodeposition of rare earth metals. By eliminating the passivation effect, the deposition process exhibits a stable current and accumulates a thick neodymium deposit on the electrode. Raman spectroscopy of the electrolyte reveals a synergetic effect between rare earth borohydride and lithium borohydride which promotes the dissociation of both borohydride salts, resulting in significantly increased ionic conductivity and electrochemical performance. Cyclic voltammetry and in-depth X-ray photoelectron spectroscopy of the deposits suggest that the electrodeposition of rare earth metals could undergo a Li-mediated reduction process. Quantitative analysis of the deposits reveals that the overall concentration of the rare earth elements reaches 75% which contains 40–48% metallic phase

Spatio-temporal patterns of attacks on human and economic losses from wildlife in Chitwan National Park, Nepal

<div><p>Wildlife attacks on humans and economic losses often result in reduced support of local communities for wildlife conservation. Information on spatial and temporal patterns of such losses in the highly affected areas contribute in designing and implementing effective mitigation measures. We analyzed the loss of humans, livestock and property caused by wildlife during 1998 to 2016, using victim family’s reports to Chitwan National Park authorities and Buffer Zone User Committees. A total of 4,014 incidents were recorded including attacks on humans, livestock depredation, property damage and crop raiding caused by 12 wildlife species. In total >400,000 US dollar was paid to the victim families as a relief over the whole period. Most of the attacks on humans were caused by rhino, sloth bear, tiger, elephant, wild boar and leopard. A significantly higher number of conflict incidents caused by rhino and elephant were observed during full moon periods. An increase in the wildlife population did not coincide with an equal rise in conflict incidents reported. Underprivileged ethnic communities were attacked by wildlife more frequently than expected. Number of attacks on humans by carnivores and herbivores did not differ significantly. An insignificant decreasing trend of wildlife attacks on humans and livestock was observed with significant variation over the years. Tiger and leopard caused >90% of livestock depredation. Tigers killed both large (cattle and buffalo) and medium sized (goat, sheep, pig) livestock but leopard mostly killed medium sized livestock. Most (87%) of the livestock killing during 2012–2016 occurred within the stall but close (<500m) to the forest edge. Both the percentage of households with livestock and average holding has decreased over the years in buffer zone. Decreased forest dependency as well as conflict mitigation measures (electric and mesh wire fences) have contributed to keep the conflict incidents in control. Strengthening mitigation measures like construction of electric or mesh wire fences and predator-proof livestock corrals along with educating local communities about wildlife behavior and timely management of problem animals (man-eater tiger, rage elephant etc.) will contribute to reduce the conflict.</p></div

Spatio-temporal patterns of attacks on human and economic losses from wildlife in Chitwan National Park, Nepal - Fig 6

<p>a) Average number of livestock depredation incident per month and season in buffer zone of Chitwan National Park during 1998–2016, b) Number of livestock killed by tiger and rhino in the distance from forest edge and park boundary.</p

Spatio-temporal patterns of attacks on human and economic losses from wildlife in Chitwan National Park, Nepal - Fig 2

<p>Wildlife attacks on humans, livestock depredation and relief payments over the years in Buffer Zone of Chitwan National Park, Nepal, a) Human death and injury b) livestock depredation caused by tiger and leopard, and its relation with people on foreign employment c) Amount of relief distribution to the victim families with timeline of relief distribution scheme. The numbers in parenthesis is the relief amount per victim of human death provisioned in relief guidelines of Buffer Zone or government, R = Nepalese Rupees, K = thousand.</p

Dependency of livestock depredation victim households on agriculture, livestock and other off-farm activities.

<p>Dependency of livestock depredation victim households on agriculture, livestock and other off-farm activities.</p

Types of loss caused by wildlife in buffer zone of Chitwan National Park.

<p>Number in the parenthesis indicates the frequency of reported cases of the incident caused by the particular wildlife species.</p

The expected and observed proportion of wildlife attacks on humans of different ethnicity.

<p>The expected and observed proportion of wildlife attacks on humans of different ethnicity.</p

Percentage of households with livestock, average livestock ownership per household and percentage of households grazing their livestock.

<p>Data for 1997 and 2006 obtained from Gurung et al. (2010).</p

Chitwan National Park and buffer zone area, showing the land cover and management sectors.

<p>The labels (1–22) represents the Buffer Zone User Committees (BZUC) and the table (top left) gives the names of respective BZUC.</p