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.

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.

In-Situ Observation of Clay Minerals Hydrated and Intercalated With Liquid Chemicals Using Film-Sealed Environmental Cell

1980 ◽  
Vol 38 ◽  
pp. 208-209 ◽  
Author(s):  
K. Fukushima ◽  
N. Kohyama ◽  
A. Fukami
Keyword(s):  
Carbon Film ◽  
Resolving Power ◽  
In Situ Observation ◽  
Interlayer Water ◽  
Saturated Water ◽  
Structure Changes ◽  
Environmental Cell ◽  
Gas Layer ◽  
20 Nm

A film-sealed high resolution environmental cell(E.C) for observing hydrated materials had been developed by us(l). Main specification of the E.C. is as follows: 1) Accelerated voltage; 100 kV. 2) Gas in the E.C.; saturated water vapour with carrier gas of 50 Torr. 3) Thickness of gas layer; 50 μm. 4) Sealing film; evaporated carbon film(20 nm thick) with plastic microgrid. 5) Resolving power; 1 nm. 6) Transmittance of electron beam; 60% at 100 kV. The E.C. had been successfully applied to the study of hydrated halloysite(2) (3). Kaolin minerals have no interlayer water and are basically non-expandable but form intercalation compounds with some specific chemicals such as hydrazine, formamide and etc. Because of these compounds being mostly changed in vacuum, we tried to reveal the structure changes between in wet air and in vacuum of kaolin minerals intercalated with hydrazine and of hydrated state of montmori1lonite using the E.C. developed by us.

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.

main principles and directions of socio-cultural re-socialization of foreign students

2021 ◽  
Vol 7 (Extra-E) ◽  
pp. 327-335
Author(s):  
Hoshang Farhad Abdullah
Keyword(s):  
Foreign Students ◽  
Social Space ◽  
Internal State ◽  
Social Adaptation ◽  
Host Society ◽  
Small Cities ◽  
Institutional Practices ◽  
Basic Principles ◽  
The Social ◽  
The Subject

The purpose of the article is to investigate the basic principles and directions of socio-cultural re-socialization of foreign students. The subject of the research is the institutional practices of re-socialization of foreign students in the conditions of a megalopolis (on the example of Moscow). The results of the work are that the author has studied the basic principles and directions of socio-cultural re-socialization of foreign students, they include 2 components, one of which provides the necessary conditioning of the internal state of a person for entering the host society, and the second-actually entering society through following certain trajectories in the social space. Thus, Russian megacities as places of subsequent social adaptation of foreign students are full of more opportunities for successful re-socialization of a criminal than small cities, but they are not without risks.

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 Aerodynamic profile drag

2021 ◽  
Author(s):  
Matej Sabo ◽  
◽  
Martin Bugaj
Keyword(s):  
Fluid Dynamics ◽  
Boundary Layer ◽  
European Union ◽  
Laminar Flow ◽  
Friction Drag ◽  
Form Drag ◽  
Basic Principles ◽  
Total Drag ◽  
Laminar Flow Control ◽  
Physical Principles

Higher awareness of aviation sustainability and environmental impact creates more research on profile drag reduction. The basic principles of aerodynamic profile drag are described and its role within the total drag. The boundary layer is defined using mathematical and physical principles of fluid dynamics. There are two types of movement inside the boundary layer: laminar and turbulent. In these, their impact on profile drag is analysed. The profile drag of a wing has two sources: form drag and friction drag. Applications with the most impact, throughout history, on both types of drag reductions were reviewed. Because most of the total drag comes from friction, researchers focus more on it compared to form drag. The significant way of reducing friction drag is postponing the transition of laminar flow into turbulent. The control of laminar flow became crucial for reducing friction drag. In the last two decades, European Union supported multiple projects concerning laminar flow control. These advancements in the field are starting to get implemented and tested on new aircraft by manufactures.

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.

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