Results 41 to 50 of about 4,537 (187)

Natural Resources and Political Patronage in Africa: An Ethnicity Level Analysis

Review of Development Economics, EarlyView.
ABSTRACT We investigate the effect of resource discoveries on ethnicity‐level political patronage in Africa using a large geospatial dataset of 254 ethnic groups in 15 countries over the period 1960–2004. We find that the first (or single first) resource discovery in a virgin ethnic homeland increases the share of cabinet posts of that ethnicity.
Sambit Bhattacharyya, Nemera Mamo
wiley   +1 more source

In Situ Carbonation of Sedimentary and Igneous Rocks of Ultramafic Composition in Jezero Crater, Mars

Journal of Geophysical Research: Planets, Volume 131, Issue 4, April 2026.
Abstract Over 3.5 years of exploration in Jezero Crater, the Perseverance rover has explored several geological units of diverse origins and natures, performing multi‐technique remote analyses of the chemistry and mineralogy of rocks with the SuperCam instrument suite.
E. Clavé, O. Beyssac, P. Beck, C. Royer, L. Mandon, N. Mangold, O. Forni, E. Dehouck, C. Bedford, A. Udry, S. Schröder, S. Bernard, C. Quantin‐Nataf, M. Loche, J. Aramendia, A. Brown, G. Caravaca, E. Cardarelli, L. Coloma, S. A. Connell, T. Fouchet, J. R. Johnson, G. Lopez‐Reyes, J. M. Madariaga, J. A. Manrique, S. Maurice, P.‐Y. Meslin, S. Le Mouélic, A. M. Ollila, P. Pilleri, C. Pilorget, K. Rammelkamp, F. Seel, J. I. Simon, U. Wolf, A. Zastrow, S. Clegg, O. Gasnault, R. C. Wiens, A. Cousin   +39 more
wiley   +1 more source

Amapari Marker Band Metal‐Enrichments: Potential Mechanisms and Implications for Surface and Subsurface Water and Weathering in Gale Crater

Journal of Geophysical Research: Planets, Volume 131, Issue 4, April 2026.
Abstract NASA's Curiosity rover is exploring a 5 km tall sedimentary mound that is hypothesized to record the transition from a warm and wet (phyllosilicate‐rich) to a cold and drier (sulfate‐rich) Mars. Evidence of magnesium sulfate‐bearing rock has shown that Curiosity has crossed through this phyllosilicate‐sulfate transition.
P. J. Gasda, E. S. Kite, L. M. Thompson, C. Mondro, W. E. Dietrich, C. M. Weitz, B. Tutolo, W. H. Farrand, E. Hausrath, A. Cowart, N. L. Lanza, K. W. Lewis, S. Gupta, A. Roberts, W. Goetz, H. E. Newsom, L. Crossey, J. Lightholder, C. Hardgrove, J. Schieber, S. P. Schwenzer, S. J. VanBommel, S. Schröder, C. D. O'Connell‐Cooper, D. Das, D. Rubin, W. Rapin, T. F. Bristow, E. Rampe, P. D. Archer Jr, C. Seeger, G. Caravaca, J. R. Johnson, S. Le Mouélic, J. A. Grant, J. Davis, J. Lasue, A. Yingst, A. B. Bryk, M. P. Lamb, W. W. Fischer, C. House, E. Dehouck, A. Essunfeld, R. Milliken, R. Sheppard, M. Minitti, D. Ming, S. Simpson, J. Frydenvang, R. M. E. Williams, R. Arvidson, R. Gellert, O. Gasnault, S. M. Clegg, D. Delapp, A. R. Vasavada, A. Fraeman   +57 more
wiley   +1 more source

The making of pure quartzose sand in continental interiors: Paraná River (Brazil and Argentina)

Sedimentology, Volume 73, Issue 3, Page 802-837, April 2026.
ABSTRACT As part of a comprehensive project on sedimentary processes in South America, this study focuses on sediment generation in the intracratonic Paraná Basin and monitors the evolution of sand composition along the Paraná River from central Brazil to the Río de la Plata estuary in Argentina.
Eduardo Garzanti, Marta Barbarano, Mara Limonta, Guido Pastore, Pieter Vermeesch, Giovanni Vezzoli   +5 more
wiley   +1 more source

Effects of different casting mould cooling rates on microstructure and properties of sand-cast Al-7.5Si-4Cu alloy [PDF]

China Foundry, 2013
In this work, Al-7.5Si-4Cu alloy melt modified by Al-10Sr, RE and Al-5Ti-B master alloys was poured into multi-step moulds made from three moulding sands, including quartz, alumina and chromite, to investigate comparatively the effects of different ...
Liu Guanglei, Si Naichao, Sun Shaochun
doaj  

Agglomeration Phenomena During Fluidized Bed Combustion/gasification of Biomass Fuels

Chemical Engineering Transactions, 2019
The objective of this research is to investigate the occurrence of agglomeration phenomena during fluidized bed processing of biomass fuels. These are to be ascribed to the alkali content in biomass materials that gives rise to low melting compounds in ...
Francesco Miccio, Annalisa Natali Murri, Valentina Medri, Elena Landi   +3 more
doaj   +1 more source

Effect of silica concentration on degree of sintering of chromite-silica ladle well filler sand based on South African raw materials

Journal of the Southern African Institute of Mining and Metallurgy, 2022
During steelmaking, one important factor for production efficiency is the free opening of the ladle nozzle during continuous casting. Free opening occurs when the well filler sand and the steel flow freely when the slide gate is opened. Well filler sands are used for the slide gate of a ladle to separate the slide gate refractory and the molten steel ...
M. Botha, J.D. Steenkamp, M.B. Shongwe, S. Brill, G. Freemantle   +4 more
openaire   +1 more source

Moon's volcanic history revealed in glassy spherules from Apollo 17 soil 76501

Meteoritics &Planetary Science, Volume 61, Issue 3, Page 389-404, March 2026.
Abstract Rapidly quenched droplets of pyroclastically erupted lava are common in lunar regolith at landing sites proximal to the maria. Here, we document the U‐Pb chronologies, major element, and trace element compositions of picritic glassy particles from Apollo 17 regolith sample 76501. These particles are dominated by high‐Ti compositions similar to
Alexander A. Nemchin, Marc D. Norman, Martin J. Whitehouse, Evgenia Salin, Nicholas E. Timms, Tao Long, Xiaochao Che, Renaud Merle, Fred Jourdan, Tao Luo   +9 more
wiley   +1 more source

Effect of cooling rate on solidification structure and linear contraction of a duplex stainless steel [PDF]

China Foundry, 2012
Cooling rate is a key factor that can drastically affect the phase transformation and thermal stress of duplex stainless steels. Therefore, in this research, different sand moulds were used to explore the influence of cooling rate on the solidification ...
Zhong Honggang, Chen Xiangru, Ao Lu
doaj  

Al‐Khadhaf: The first camera‐observed (H5–6) meteorite fall from Oman

Meteoritics &Planetary Science, Volume 61, Issue 3, Page 522-547, March 2026.
Abstract A fireball camera system installed in 2022 by the Oman Meteorite Monitoring Project (OMMP) as part of the Global Fireball Observatory (GFO) recorded a 3.2 s fireball on March 8, 2022 at 8:15 p.m. UTC. A meteoroid of 4 ± 2 kg entered the atmosphere at 14.0 km/s.
Anna Zappatini, Edwin Gnos, Beda A. Hofmann, Urs Eggenberger, Pascal M. Kruttasch, Frank Gfeller, Mohammad Tauseef, Ingo Leya, Hadrien A. R. Devillepoix, Eleanor K. Sansom, Martin Cupák, Sophie E. Deam, Thomas W. C. Stevenson, Peter Jenniskens, Sebastian Lindemann, Beat Booz, Muati. S. Al‐Muati, Abdulmunaim A. Al‐Zakwani, Hussain A. Al‐Ghafri   +18 more
wiley   +1 more source