China
Africa
Explore chapters and articles related to this topic
Electrical Aspects
Published in Frank R. Spellman, The Science of Wind Power, 2022
The word electricity is derived from the Greek word “electron” (meaning amber). Amber is a translucent (semitransparent) yellowish fossilized mineral resin. The ancient Greeks used the words “electric force” in referring to the mysterious forces of attraction and repulsion exhibited by amber when it was rubbed with a cloth. They did not understand the nature of this force. They could not answer the question, “What is electricity?” The fact is this question remains unanswered. Today, we often attempt to answer this question by describing the effect and not the force. That is, the standard answer given is, “the force which moves electrons” is electricity, which is about the same as defining a sail as “that force which moves a sailboat.”
Naphthenic Acids Environmental Occurrence and Chromatographic Analysis
Published in Leo M. L. Nollet, Dimitra A. Lambropoulou, Chromatographic Analysis of the Environment, 2017
Adeola Adenugba, John V. Headley, Kerry Peru, Dena McMartin
In the environment, NAs exhibit different characteristics depending on the geographical location (Headley et al., 2009). NAs are viscous liquids at room temperature. They differ in color from pale yellow to dark amber. They have low water solubilities (<50 mg L−1 at pH 7) but are readily soluble in organic solvents and oils. Their dissociation constants range from 10−5 to 10−6, comparable to those of higher-molecular weight fatty acids (Brient et al., 1995). As the molecular weight of NAs increases, so do their polarity and nonvolatility, giving each individual compound unique physical and chemical properties (Headley and McMartin, 2004) as shown in Table 18.2.
Bonding agents
Published in Jill L. Baker, Technology of the Ancient Near East, 2018
Amber is an organic material that comes from resin-bearing trees that fell millions of years ago in the Middle Cretaceous to Tertiary periods. The fallen trees were eventually covered by sediment as they settled into the ground, thus producing fossilized resin, known as amber (Serpico 2009:451). Amber occurs as a pale yellow or brown color that can turn to brownish-red over time. Deposits have been found around the Baltic Sea, across the European continent from Russia to England, and in Sicily, Austria, Israel, Jordan, Lebanon, Romania, and Poland (Serpico 2009:451).
Influence of organic dispersant on nuclear grade anion exchange resin and their interaction behavior
Published in Journal of Nuclear Science and Technology, 2023
Yu Wang, Tianping Wang, Xuxiang Jia, Chunsong Ye
The changes of morphology and composition for resin after adsorbing and desorbing PAA are investigated, which is beneficial to analyze the interaction feature between PAA and anion exchange resin. Appearance images of the FRs, ARs, and DRs indicate no significant change of color and appearance for resin, which are all the amber translucent beads (Figure 7(a)). SEM images show that the FRs, ARs, and DRs possess intact, smooth, and spherical structures with no significant damage (Figure 7(b)). Partially aggregated molecular clusters are observed on the surface of the ARs at high magnification (50,000 times), while those of the FRs are not observed (Figure 7(c)). It is because PAA could not diffuse into the inside of resin. Therefore, PAA could accumulate on the resin surface. The results of kinetic analysis prove this speculation. Furthermore, no similar molecular clusters are observed on the surface of the DRs, which further indicates that NaOH could desorb PAA from resin.
Late Bronze Age Metal Exploitation and Trade: Sardinia and Cyprus
Published in Materials and Manufacturing Processes, 2020
Serena Sabatini, Fulvia Lo Schiavo
Provenance studies carried out on bronze and copper finds from the Mediterranean and continental Europe now demonstrate that the LBA metal trade was broad and complex. Furthermore, it is also clear that continental Bronze Age communities and the Mediterranean world networked in manifold ways in what was apparently a great need for metal. The presence of several ”foreign/exotic” goods and materials (such as Mesopotamian glass, Mycenaean ceramics, and Baltic amber[205]), and the abundance of tin in local metal production, strongly suggest that Nuragic communities were actively involved in the international metal trade. A topic for future studies would be to investigate how we can better define and understand what we daringly called Nuragic maritime “enterprises”, and identify what the other driving forces were that complemented the picture and which acted side by side in the long-distance metal trade.
Molecular simulation of binary phase diagrams from the osmotic equilibrium method: vapour pressure and activity in water–ethanol mixtures
Published in Molecular Physics, 2018
Michael Bley, Magali Duvail, Philippe Guilbaud, Christophe Penisson, Johannes Theisen, Jean-Christophe Gabriel, Jean-François Dufrêche
Classical MD simulations of pure water, pure ethanol and their mixtures at different ethanol mole fractions xE ranging from 0.1 to 0.9 were carried out with SANDER14, a module of AMBER14 [31], using explicit polarisation in the NPT and NVT ensembles. Periodic boundary conditions were applied to the simulation box in all directions. Equations of motion were numerically integrated using a 1.0 fs time step and long-range interactions have been calculated using the particle-mesh Ewald method [32]. Systems were equilibrated at 298.15 K and 1 bar (0.1 MPa) for 10 ns in the NPT ensemble, and production runs were afterwards conducted in the NVT ensemble for at least 15 ns. All atomic coordinates were written to the trajectory file every picosecond. Here, the van der Waals energy is described by a 12–6 Lennard-Jones potential. Water molecules were described by the rigid POL3 model [33,34], taking into account polarisation. The polarisable parm99 AMBER force field [35] was used to model the ethanol molecule (Table 1). Atomic partial charges on the ethanol were calculated using the restricted electrostatic potential procedure [36,37]. The atomic charges of the individual atoms are depicted in Figure 1. These sets of parameters provide a reasonable agreement of experimental [38] (ρExp. = 0.786 g cm−3) and calculated density (ρSim. = 0.760 g cm−3) for pure ethanol at 298.15 K.