Abstract The paper comprises new analytical data on the nature and occurrence of gold in solid pyrobitumen, closely associated with main gold-bearing sulfide arsenic ores Bakyrchik deposit (Kazakhstan), related to post-collisional magmatic-hydrothermal origin. Gold mineralization occurs mainly form an “invisible” type structures arsenian pyrite arsenopyrite, gold-organic compounds pyrobitumen c...

The purpose of this research is to establish the grounds for a critical social scientific analysis of mineral development based upon the case study of women in informal peasant gold mining or garimpagem1 in the Brazilian Amazon. Situated at the local/regional level of analysis, this case study illustrates the main tensions of contemporary mineral development. First, the region’s mineral develop...

This paper proposes some modest improvements to Extractor, a state-of-the-art keyphrase extraction system, by using a terabyte-sized corpus to estimate the informativeness and semantic similarity of keyphrases. We present two techniques to improve the organization and remove outliers of lists of keyphrases. The first is a simple ordering according to their occurrences in the corpus; the second ...

The ionic liquid A327H+Cl− is generated by reaction of the tertiary amine A327 (industrial mixture tri-octyl and tri-decyl amines) hydrochloric acid solutions. In this study, extraction Au(III) under various variables, including metal concentrations, was investigated. Results indicate that A327H+AuCl4− formed an exothermic (ΔH° = −3 kJ/mol) in organic solution. Aqueous strength influences forma...

Betaine is one of most studied biologically active compounds, due its role in the main biological processes. Although it may be found in several plants and roots, such as the Beta vulgaris family, present in typical diets, just a few analytical methods have been developed for its extraction from roots. A new, quick and effective procedure for the isolation and determination of betaine from two ...

Mathematical formulae in academic texts significantly contribute to the overall semantic content of such texts, especially in the fields of Science, Technology, Engineering and Mathematics. Knowing the definitions of the identifiers in mathematical formulae is essential to understand the semantics of the formulae. Similar to the sense-making process of human readers, mathematical information re...

Introduction: Nearly four decades of experimental studies have failed to agree on an isotopic composition for solar wind (SW) nitrogen implanted in lunar regolith grains. Estimates of ! 15 N range from > +200 ‰ [1] to < -250 ‰ [2]. Its actual value is crucial, not only for untangling component mixtures in the lunar system but also in elucidating the sources and isotopic evolution of N in other ...

Ethylene glycol bisthioglycolate modified gold nanoparticles grafted Mn doped Fe3O4 nanoparticles (Au@Mn-Fe3O4 NPs) adsorbent was synthesized and applied for extraction and preconcentration of trace amounts of Ag+ and Pb2+ ions in artificial and natural saliva. The adsorbent was characterized by transmission electron microscopy (...

Abstract A new adsorbent, ethylene glycol bisthioglycolate modified gold nanoparticles grafted Mn doped Fe3O4 nanoparticles (EGBTG-Au@Mn-Fe3O4 NPs) were synthesized through chemical precipitation followed by an oxidative Mn doping process to use for extraction and preconcentration of trace amounts of Hg, and Cu ions in artificial and natural saliva. The prepared adsorbent was characterize...

Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs a...