I.—The Geological Age of the Carrara Marbles

1915 ◽  
Vol 2 (7) ◽  
pp. 289-294
Author(s):  
T. G. Bonney ◽  
H. H. Winwood
Keyword(s):  
Mountain Regions ◽  
Geological Age ◽  
The Subject

The statuary marbles of Carrara have been repeatedly asserted to be metamorphic limestones of earlier Mesozoic or later Palæozoic age. Similar statements were once frequent in regard to other mountain regions, but they have one by one dropped out of geological literature. This, however, is such a hardy perennial as to be still repeated in petrological and other textbooks. Doubts, however, were felt by the first author in 1878, and these became almost certainties after 1886, but as each visit was only for a few hours, and did not allow of a proper examination of the rocks in situ, he deferred writing on the subject till he could spend a longer time at Carrara. That opportunity, however, never came, and is not now likely to occur ; but on finding not long since that his friends, Professor Boyd Dawkins and the Rev. H. H. Winwood, had visited the quarries in 1898, and the latter had published an account of the district, with a sketch-section drawn by the former, he communicated with them, and the following paper summarizes the experience of the three, which it is hoped may help in laying another metamorphic ghost.

Direct Observations of the Epitaxial Growth of Sputtered Ag on Si

1973 ◽  
Vol 31 ◽  
pp. 122-123
Author(s):  
J. S. Maa ◽  
Thos. E. Hutchinson
Keyword(s):  
Epitaxial Growth ◽  
Film Growth ◽  
Ion Beam ◽  
Ion Beam Sputtering ◽  
Microscopy Technique ◽  
Direct Observations ◽  
In Situ Electron Microscopy ◽  
Beam Sputtering ◽  
The Subject

The growth of Ag films deposited on various substrate materials such as MoS2, mica, graphite, and MgO has been investigated extensively using the in situ electron microscopy technique. The three stages of film growth, namely, the nucleation, growth of islands followed by liquid-like coalescence have been observed in both the vacuum vapor deposited and ion beam sputtered thin films. The mechanisms of nucleation and growth of silver films formed by ion beam sputtering on the (111) plane of silicon comprise the subject of this paper. A novel mode of epitaxial growth is observed to that seen previously.The experimental arrangement for the present study is the same as previous experiments, and the preparation procedure for obtaining thin silicon substrate is presented in a separate paper.

scholarly journals Influence of Hydrogeochemistry on Tunnel Drainage in Evaporitic Formations: El Regajal Tunnel Case Study (Aranjuez, Spain)

2021 ◽  
Vol 13 (3) ◽  
pp. 1505
Author(s):  
Ignacio Menéndez Pidal ◽  
Jose Antonio Mancebo Piqueras ◽  
Eugenio Sanz Pérez ◽  
Clemente Sáenz Sanz
Keyword(s):  
High Speed ◽  
Civil Engineering ◽  
Saturation Index ◽  
The Subject ◽  
Under Construction ◽  
Underground Flow ◽  
Very High ◽  
Over Time

Many of the large number of underground works constructed or under construction in recent years are in unfavorable terrains facing unusual situations and construction conditions. This is the case of the subject under study in this paper: a tunnel excavated in evaporitic rocks that experienced significant karstification problems very quickly over time. As a result of this situation, the causes that may underlie this rapid karstification are investigated and a novel methodology is presented in civil engineering where the use of saturation indices for the different mineral specimens present has been crucial. The drainage of the rock massif of El Regajal (Madrid-Toledo, Spain, in the Madrid-Valencia high-speed train line) was studied and permitted the in-situ study of the hydrogeochemical evolution of water flow in the Miocene evaporitic materials of the Tajo Basin as a full-scale testing laboratory, that are conforms as a whole, a single aquifer. The work provides a novel methodology based on the calculation of activities through the hydrogeochemical study of water samples in different piezometers, estimating the saturation index of different saline materials and the dissolution capacity of the brine, which is surprisingly very high despite the high electrical conductivity. The circulating brine appears unsaturated with respect to thenardite, mirabilite, epsomite, glauberite, and halite. The alteration of the underground flow and the consequent renewal of the water of the aquifer by the infiltration water of rain and irrigation is the cause of the hydrogeochemical imbalance and the modification of the characteristics of the massif. These modifications include very important loss of material by dissolution, altering the resistance of the terrain and the increase of the porosity. Simultaneously, different expansive and recrystallization processes that decrease the porosity of the massif were identified in the present work. The hydrogeochemical study allows the evolution of these phenomena to be followed over time, and this, in turn, may facilitate the implementation of preventive works in civil engineering.

Żelazna Nowa, stanowisko 2. Cmentarzysko kultury przeworskiej z Zapilcza na południowym Mazowszu

2020 ◽  
Author(s):  
Małgorzata Cieślak-Kopyt ◽  
Dorota Pogodzińska
Keyword(s):  
Material Culture ◽  
Archaeological Heritage ◽  
Non Invasive ◽  
Vistula River ◽  
Animal Bones ◽  
The Subject ◽  
Metal Detectors ◽  
Przeworsk Culture ◽  
Small Finds

The subject of the monograph, published as the 10th volume of the Saved Archaeological Heritage series, are the results of rescue excavations on a cemetery from the period of Roman influence on the Vistula River near Magnuszew in southern Mazovia (Poland), carried out several years ago at the initiative of the Museum in Radom. This necropolis, like many similar ones throughout the country, was systematically destroyed as a result of agricultural activities, and in recent years also through illegal prospection with the use of metal detectors. Archaeologists, with the cooperation of numerous volunteers, managed to protect against further destruction about 60 graves (urned and urnless) from the period between the 1st century BC and the 3rd century CE. These are an evidence of the settlement of the region by people whose material traces are referred to in the archaeological nomenclature as the Przeworsk culture (associated mainly with the Germanic tribes). The cinerary graves were equipped with ceramics, metal parts of clothing, tools, less often weapons, glass beads, imported vessels or dice. Among the forms of graves, the so-called groove object stands out: a kind of rectangular grave feature tied with survival to the beginnings of our era of Celtic traditions, arriving here from northern Małopolska. In addition to the standard catalogue with the description of graves, pottery and small finds, and very detailed illustration plates, the monograph includes an analysis of material culture and forms of burial, photographs of selected finds and very extensive specialist reports. The latter include both osteological materials (anatomo-anthropological analysis, analysis of animal bones placed in the graves), as well as other ecofacts and individual categories of furnishings (glass, faience, iron and bronze objects). The whole is complemented by clear plans with the location of graves and artifacts in the necropolises, as well as with the results of non-invasive research going far beyond the excavated area and of key importance for further in situ protection of this extremely valuable monument.

scholarly journals Characterization of interferences to in situ observations of <i>δ</i><sup>13</sup>CH<sub>4</sub> and C<sub>2</sub>H<sub>6</sub> when using a cavity ring-down spectrometer at industrial sites

2017 ◽  
Vol 10 (6) ◽  
pp. 2077-2091 ◽  
Author(s):  
Sabina Assan ◽  
Alexia Baudic ◽  
Ali Guemri ◽  
Philippe Ciais ◽  
Valerie Gros ◽  
...  
Keyword(s):  
Near Infrared ◽  
Field Tests ◽  
Isotopic Signature ◽  
Ambient Conditions ◽  
Industrial Sites ◽  
Source Determination ◽  
Infrared Spectral ◽  
The Subject

Abstract. Due to increased demand for an understanding of CH4 emissions from industrial sites, the subject of cross sensitivities caused by absorption from multiple gases on δ13CH4 and C2H6 measured in the near-infrared spectral domain using CRDS has become increasingly important. Extensive laboratory tests are presented here, which characterize these cross sensitivities and propose corrections for the biases they induce. We found methane isotopic measurements to be subject to interference from elevated C2H6 concentrations resulting in heavier δ13CH4 by +23.5 ‰ per ppm C2H6 ∕ ppm CH4. Measured C2H6 is subject to absorption interference from a number of other trace gases, predominantly H2O (with an average linear sensitivity of 0.9 ppm C2H6 per  % H2O in ambient conditions). Yet, this sensitivity was found to be discontinuous with a strong hysteresis effect and we suggest removing H2O from gas samples prior to analysis. The C2H6 calibration factor was calculated using a GC and measured as 0.5 (confirmed up to 5 ppm C2H6). Field tests at a natural gas compressor station demonstrated that the presence of C2H6 in gas emissions at an average level of 0.3 ppm shifted the isotopic signature by 2.5 ‰, whilst after calibration we find that the average C2H6 : CH4 ratio shifts by +0.06. These results indicate that, when using such a CRDS instrument in conditions of elevated C2H6 for CH4 source determination, it is imperative to account for the biases discussed within this study.

scholarly journals The Role of Al3+-Based Aqueous Electrolytes in the Charge Storage Mechanism of MnOx Cathodes

2020 ◽  
Author(s):  
Véronique Balland ◽  
Mickaël Mateos ◽  
Kenneth D. Harris ◽  
Benoit Limoges
Keyword(s):  
Manganese Oxide ◽  
Critical Analysis ◽  
Charge Storage ◽  
Aqueous Electrolytes ◽  
Storage Mechanism ◽  
Main Charge ◽  
Charge Storage Mechanism ◽  
The Subject

<p>Rechargeable aqueous aluminium batteries are the subject of growing interest, but the charge storage mechanisms at manganese oxide-based cathodes remain poorly understood with as many mechanisms as studies. Here, we use an original <i>in situ</i> spectroelectrochemical methodology to unambiguously demonstrate that the reversible proton-coupled MnO<sub>2</sub>-to-Mn<sup>2+</sup> conversion is the main charge storage mechanism occurring at MnO<sub>2</sub> cathodes over a range of slightly acidic Al<sup>3+</sup>-based aqueous electrolytes. In Zn/MnO<sub>2</sub> assemblies, this mechanism is associated with high gravimetric capacity and discharge potentials, up to 560 mAh·g<sup>-1</sup> and 1.76 V respectively, attractive efficiencies (<i>CE</i> > 98.5 % and <i>EE</i> > 80%) and excellent cyclability (> 750 cycles at 10 A·g<sup>-1</sup>). Finally, we conducted a critical analysis of the data previously published on MnO<sub>x</sub> cathodes in Al<sup>3+</sup>-based aqueous electrolytes to conclude on a universal charge storage mechanism, <i>i.e.</i>, the reversible electrodissolution/electrodeposition of MnO<sub>2</sub>.<i></i></p>

scholarly journals Graphene spin-coated electrode for polyacrylonitrile acoustic nanogenerators

2021 ◽  
Author(s):  
Sedigheh Aghayari
Keyword(s):  
Nickel Nanoparticles ◽  
In Situ Synthesis ◽  
Coated Electrode ◽  
The Subject ◽  
First Time ◽  
Piezoelectric Nanogenerators ◽  
High Dust ◽  
Screen Ink

Abstract In recent years piezoelectric nanogenerators, due to their more durability in high dust or humidity are more attractive than triboelectric ones. So, increasing their outputs is the subject of much researches. I focused on electrodes of the acoustic nanofibers nanogenerators for the first time. Here, I introduced a new electrode that is cheaper and does not result in lower outputs. Here for the first time graphene spin-coated ink was used for polyacrylonitrile-based acoustic nanogenerator. The results of the tests compared with the in-situ synthesis of nickel nanoparticles on the layer and using graphene spin-coated screen ink and conductive tapes. Finally, producing sound by this graphene ink was done too.

scholarly journals IV. On the relation of the reptiliferous sandstone of Elgin to the upper old red sandstone

1886 ◽  
Vol 39 (239-241) ◽  
pp. 394-404
Keyword(s):  
Red Sandstone ◽  
The North ◽  
Geological Age ◽  
The Subject ◽  
The City

The question of the geological age of the yellow sandstones of the district lying to the north of the city of Elgin has been, as is well known, the subject of very animated discussions among geologists. Some have even gone so far as to assert that the evidence on the question, which has been adduced by palaeontologists, is absolutely incapable of reconciliation with that relied upon by stratigraphists.

Wingless induces transdetermination in developing Drosophila imaginal discs

Development ◽  
1995 ◽  
Vol 121 (5) ◽  
pp. 1263-1272 ◽  
Author(s):  
L. Maves ◽  
G. Schubiger
Keyword(s):  
Molecular Level ◽  
Ectopic Expression ◽  
Imaginal Discs ◽  
Developmental Studies ◽  
New Approach ◽  
Cell Determination ◽  
Disc Cells ◽  
The Subject ◽  
Insight Into

Drosophila imaginal discs, the precursors of the adult fly appendages, have been the subject of intensive developmental studies, particularly on cell determination. Cultured disc fragments are recognized not only for the ability to maintain their determined state through extra cell divisions but also for the ability to transdetermine, or switch to the determined state of a different disc. An understanding of transdetermination at a molecular level will provide further insight into the requirements for maintaining cell determination. We find that ectopic expression of the Drosophila gene wingless induces transdetermination of foreleg imaginal disc cells to wing cells. This transdetermination occurs in foreleg discs of developing larvae without disc fragmentation. The in situ-transdetermining cells localize to the dorsal region of the foreleg disc. This wingless-induced transdetermination event is remarkably similar to the leg-to-wing switch that occurs after leg disc culture. Thus we have identified a new approach to a molecular dissection of transdetermination.

scholarly journals Solar and Interplanetary Dynamics (Symposium Summary)

1980 ◽  
Vol 91 ◽  
pp. 547-552 ◽  
Author(s):  
M. Kuperus
Keyword(s):  
Solar Atmosphere ◽  
Interplanetary Medium ◽  
Temporal Variations ◽  
Magnetic Structures ◽  
Solar Observations ◽  
The Earth ◽  
The Subject ◽  
Physical Phenomena ◽  
Made In

Solar and interplanetary dynamics comprises dynamic and plasma-physical phenomena in the solar atmosphere, the corona and the interplanetary medium in the broadest sense. In this symposium, however, one has essentially tried to restrict the subject matter to the study of the propagation of a disturbance, produced in the solar atmosphere, through the corona and the interplanetary medium. In studying solar and interplanetary dynamical phenomena we find ourselves in the unique position, with respect to other astrophysical disciplines, to be able to relate solar observations obtained with the highest possible spectral, spatial and time resolution with in situ measurements made in the interplanetary medium. It has now turned out that the two fundamental questions to be answered are:a) How does the medium in between the sun and the earth and beyond the earth's orbit, the socalled heliosphere, look like? Does a basic undisturbed heliosphere actually exist, and is one able to model its observed magnetic structures and plasma motions with their spatial and temporal variations?b) How and where in the solar atmosphere are the disturbances generated and what are the characteristic time scales, geometries and energies involved?

Optical Methods To Measure Shape and Size

1987 ◽  
Vol 1 (1) ◽  
pp. 27-38 ◽  
Author(s):  
P.M. Boone
Keyword(s):  
Resolving Power ◽  
Optical Methods ◽  
Incoherent Light ◽  
Basic Principles ◽  
The Subject ◽  
Moiré Techniques ◽  
Living Objects ◽  
Mechanical Sensing ◽  
Physical Principles

A number of methods are available to quantify exterior size and shape of living and non-living objects. Relevant items for dentistry are the exterior of face and skull and the surface of dental casts. To the best of our knowledge, dentitions have not yet been measured in situ. The optical methods using incoherent light are mechanical sensing of casts, visual stereometry (on the subject or on stereophotographic pairs), moire techniques, and optical-sensor morphometry. It will be shown that the three latter systems in fact rely on the same physical principles, although they involve quite different technologies. On the other hand, coherent optical techniques, such as holography and contouring holographic interferometry, are presented. The basic principles of the different techniques are shown, and their main features in relation to applications to the dental object discussed. Main features include: resolving power, range, time needed for a measurement, requirements for the surface of the object, and ease of selection and collection of data. Examples of methods from the literature and from work by the author are given.

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