Oxide nanoparticles

2021 ◽  
pp. 166-199
Author(s):  
Falko P. Netzer ◽  
Claudine Noguera
Keyword(s):  
Finite Size ◽  
Point Of View ◽  
Three Dimensions ◽  
Aqueous Environment ◽  
Condensed Phases ◽  
Fundamental Point ◽  
Thermodynamic Conditions ◽  
Cation Mixing ◽  
Novel Applications ◽  
Dimensions Of Space

Oxide micro- and nanoparticles are ubiquitous in the natural environment. They have long been used as catalysts, but have found novel applications with the advent of nanotechnologies. From a fundamental point of view, they bridge the gap between the properties of isolated atoms or molecules and those of bulk condensed phases. They present a large spectrum of atomic and electronic structures, due to their finite size in the three dimensions of space and the fact that their atoms are nearly all surface atoms. They represent the first stages of nucleation and growth of larger size oxides, and their stability and properties which depend upon the thermodynamic conditions under which they are formed, largely impact the final product. This chapter reviews their specific properties and analyses their physical origin, both when they are produced in the gas phase, in an aqueous environment, or when cation mixing takes place.

Radiation Damage in Ceramics

1982 ◽  
Vol 40 ◽  
pp. 600-603
Author(s):  
T. E. Mitchell ◽  
M. R. Pascucci ◽  
R. A. Youngman
Keyword(s):  
Radiation Damage ◽  
Outer Space ◽  
Point Of View ◽  
Nuclear Waste Storage ◽  
Waste Storage ◽  
Storage Media ◽  
Transmission Electron ◽  
Fundamental Point ◽  
Small Defect ◽  
Present Understanding

1. Introduction. Studies of radiation damage in ceramics are of interest not only from a fundamental point of view but also because it is important to understand the behavior of ceramics in various practical radiation enyironments- fission and fusion reactors, nuclear waste storage media, ion-implantation devices, outer space, etc. A great deal of work has been done on the spectroscopy of point defects and small defect clusters in ceramics, but relatively little has been performed on defect agglomeration using transmission electron microscopy (TEM) in the same kind of detail that has been so successful in metals. This article will assess our present understanding of radiation damage in ceramics with illustrations using results obtained from the authors' work.

The Sea Fight Tomorrow

2018 ◽  
Author(s):  
Donald C. Williams
Keyword(s):  
Three Dimensions ◽  
The Past ◽  
The World ◽  
The Future ◽  
Metaphysics Of Time ◽  
Manifold Theory ◽  
Dimensions Of Space

This chapter is the first of this book to deal specifically with the metaphysics of time. This chapter defends the pure manifold theory of time. On this view, time is just another dimension of extent like the three dimensions of space, the past, present, and future are equally real, and the world is at bottom tenseless. What is true is eternally true. For example, it is now true that there will be a sea fight tomorrow or that there will not be a sea fight tomorrow. It is argued that the pure manifold theory does not entail fatalism and that contingent statements about the future do not imply that only the past and present exist.

scholarly journals An exceptionally preserved conulariid from Ordovician erratics of Northern European Lowlands

PalZ ◽  
2021 ◽  
Author(s):  
Consuelo Sendino ◽  
Martin M. Bochmann
Keyword(s):  
Internal Structure ◽  
Late Pleistocene ◽  
Point Of View ◽  
Three Dimensions ◽  
Northern European ◽  
Current Location ◽  
Transport Direction ◽  
First Time ◽  
Erratic Boulder

AbstractA conulariid preserved in three dimensions from Ordovician fluvioglacial erratics of the Northern European Lowlands (North German Plain) is described under open nomenclature. It is assigned to the genus Conularia with similarities to Baltoscandian conulariids. The lithology of the erratic boulder and fauna contained in it provide important information on the origin and transport direction of the sediment preserved in a kame from the Saalian glaciation. This paper deals with the site of origin of the boulder in Baltoscandia analysing the comprised palaeofauna, from a palaeostratigraphic and palaeogeographic point of view, from its deposition in Ordovician times until its arrival at its current location in the Late Pleistocene. It also reveals for the first time the internal structure of the conulariid aperture.

scholarly journals LARGE QUANTUM GRAVITY EFFECTS: CYLINDRICAL WAVES IN FOUR DIMENSIONS

2000 ◽  
Vol 09 (06) ◽  
pp. 669-686 ◽  
Author(s):  
MARÍA E. ANGULO ◽  
GUILLERMO A. MENA MARUGÁN
Keyword(s):  
Quantum Gravity ◽  
Symmetry Axis ◽  
Point Of View ◽  
Three Dimensions ◽  
Asymptotic Region ◽  
Four Dimensions ◽  
Cylindrical Waves ◽  
Significant Difference ◽  
Gravity Effects ◽  
Linearly Polarized

Linearly polarized cylindrical waves in four-dimensional vacuum gravity are mathematically equivalent to rotationally symmetric gravity coupled to a Maxwell (or Klein–Gordon) field in three dimensions. The quantization of this latter system was performed by Ashtekar and Pierri in a recent work. Employing that quantization, we obtain here a complete quantum theory which describes the four-dimensional geometry of the Einstein–Rosen waves. In particular, we construct regularized operators to represent the metric. It is shown that the results achieved by Ashtekar about the existence of important quantum gravity effects in the Einstein–Maxwell system at large distances from the symmetry axis continue to be valid from a four-dimensional point of view. The only significant difference is that, in order to admit an approximate classical description in the asymptotic region, states that are coherent in the Maxwell field need not contain a large number of photons anymore. We also analyze the metric fluctuations on the symmetry axis and argue that they are generally relevant for all of the coherent states.

scholarly journals The wave pattern of a doublet in a stream

1928 ◽  
Vol 121 (788) ◽  
pp. 515-523 ◽  
Keyword(s):  
Surface Effect ◽  
Ideal Point ◽  
Finite Size ◽  
Wave Pattern ◽  
Wave Resistance ◽  
Point Of View ◽  
The Body ◽  
Surface Elevation ◽  
More Care ◽  
Forced Waves

The following paper is a study of the surface waves caused by a doublet in a uniform stream, and in particular the variation in the pattern with the velocity of the stream or the depth of the doublet. In most recent work on this subject attention has been directed more to the wave resistance, which can be evaluated with less difficulty than is involved in a detailed study of the waves; in fact, it would seem that it is not necessary for that purpose to know the surface elevation completely, but only certain significant terms at large distances from the disturbance. Recent experimental work has shown con­siderable agreement between theoretical expressions for wave resistance and results for ship models of simple form, and attempts have been made at a similar comparison for the surface elevation in the neighbourhood of the ship. In the latter respect it may be necessary to examine expressions for the surface elevation with more care, as they are not quite determinate; any suitable free disturbance may be superposed upon the forced waves. For instance, it is well known that in a frictionless liquid a possible solution is one which gives waves in advance as well as in the rear of the ship, and the practical solution is obtained by superposing free waves which annul those in advance, or by some equivalent artifice. This process is simple and definite for an ideal point disturbance, but for a body of finite size or a distributed disturbance the complete surface elevation in the neighbourhood of the body requires more careful specification as regards the local part due to each element. It had been intended to consider some expressions specially from this point of view, but as the matter stands at present it would entail a very great amount of numerical calculation, and the present paper is limited to a much simpler problem although also involving considerable computation. A horizontal doublet of given moment is at a depth f below the surface of a stream of velocity c ; the surface effect may be described as a local disturbance symmetrical fore and aft of the doublet together with waves to the rear. Two points are made in the following work.

Higher-Order Multilevel Solvers for the EHL Line and Point Contact Problem

1994 ◽  
Vol 116 (4) ◽  
pp. 741-750 ◽  
Author(s):  
C. H. Venner
Keyword(s):  
Contact Problem ◽  
Computing Time ◽  
Point Contact ◽  
Higher Order ◽  
Second Order ◽  
Point Of View ◽  
First Order ◽  
Fundamental Point ◽  
Numerical Solver ◽  
Circular Contact

This paper addresses the development of efficient numerical solvers for EHL problems from a rather fundamental point of view. A work-accuracy exchange criterion is derived, that can be interpreted as setting a limit to the price paid in terms of computing time for a solution of a given accuracy. The criterion can serve as a guideline when reviewing or selecting a numerical solver and a discretization. Earlier developed multilevel solvers for the EHL line and circular contact problem are tested against this criterion. This test shows that, to satisfy the criterion a second-order accurate solver is needed for the point contact problem whereas the solver developed earlier used a first-order discretization. This situation arises more often in numerical analysis, i.e., a higher order discretization is desired when a lower order solver already exists. It is explained how in such a case the multigrid methodology provides an easy and straightforward way to obtain the desired higher order of approximation. This higher order is obtained at almost negligible extra work and without loss of stability. The approach was tested out by raising an existing first order multilevel solver for the EHL line contact problem to second order. Subsequently, it was used to obtain a second-order solver for the EHL circular contact problem. Results for both the line and circular contact problem are presented.

A METAMAGNETIC QUANTUM CRITICAL ENDPOINT IN Sr3Ru2O7

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3258-3264 ◽  
Author(s):  
S. A. GRIGERA ◽  
A. P. MACKENZIE ◽  
A. J. SCHOFIELD ◽  
S. R. JULIAN ◽  
G. G. LONZARICH
Keyword(s):  
Quantum Critical Point ◽  
Point Of View ◽  
Zero Temperature ◽  
Tuning Parameters ◽  
First Order ◽  
End Point ◽  
Fundamental Point ◽  
New Type ◽  
Quantum Critical ◽  
The Magnetic Field

In this paper, we discuss the concept of a metamagnetic quantum critical end-point, consequence of the depression to zero temperature of a critical end-point terminating a line of first order first transitions. This new type of quantum critical point (QCP) is interesting both from a fundamental point of view: a study of a symmetry conserving QCP, and because it opens the possibility of the use of symmetry breaking tuning parameters, notably the magnetic field. In addition, we discuss the experimental evidence for the existence of such a QCP in the bilayer ruthenate Sr3Ru2O7.

scholarly journals EPISTEMOLOGI AL-QURAN DALAM MEMBANGUN SAINS ISLAM

2016 ◽  
Vol 26 (1) ◽  
Author(s):  
Iing Mishbahuddin
Keyword(s):  
Point Of View ◽  
Three Dimensions ◽  
Building Science ◽  
Philosophical Framework ◽  
Ontological Dimension ◽  
Theory Of Value ◽  
True Knowledge ◽  
Object Of Study ◽  
Epistemological Dimension ◽  
Science Part

Abstract: This article aims to elaborate on the Quran as the basis of Islamic epistemology in building science. The concept of science in the Quran, from the point of view of philosophy. Framework used to analyze this theme is the philosophical framework. In the paradigm of philosophy, science concepts can be classified in three dimensions; the first, an epistemological dimension, namely the study of philosophy from the aspect of how to acquire knowledge. Part of this philosophy is called the theory of knowledge, namely methodology to gain knowledge or science, or how to obtain a true knowledge; second, the ontological dimension, namely the branch of philosophy that discusses the object of study of science, or the nature of the study of science; and the third, axiological dimension, namely the branch of philosophy that discusses the purpose and use value and the value of the benefits of science. Part of this philosophy better known as the theory of value. And what about his role in building the Islamic sciences in Islamic universities in particular and in the Islamic world in general. Abstrak: Artikel ini bertujuan untuk mengelaborasi al-Quran sebagai landasan epistemologi dalam membangun sains Islam. Konsep ilmu dalam al-Quran, ditinjau dari sudut pandang filsafat. Kerangka yang dipakai untuk menganalisis tema ini adalah kerangka pemikiran filsafat. Dalam paradigma filsafat, konsep ilmu dapat diklasifikasi dalam tiga dimensi; pertama, dimensi epistemologis, yakni kajian filsafat dari aspek bagaimana cara memperoleh ilmu pengetahuan. Bagian filsafat ini disebut teori ilmu pengetahuan, yaitu metodologi untuk mendapatkan ilmu pengetahuan, atau cara mendapatkan pengetahuan yang benar; kedua, dimensi ontologis, yakni cabang filsafat yang membahas tentang objek kajian ilmu pengetahuan, atau hakikat segala yang menjadi kajian ilmu; dan ketiga, dimensi aksiologis, yakni cabang filsafat yang mem-bahas tentang tujuan dan nilai guna serta nilai manfaat ilmu pengetahuan. Bagian filsafat ini lebih dikenal dengan teori nilai. Dan bagaimana peranannya dalam membangun sains Islam di perguruan tinggi Islam khususnya dan di dunia Islam pada umumnya. Keywords: al-Quran, ayat al-matluwah, ayat al-majluwah, al-‘ilm, al-ḥikmah, dan al-ma‘rifah.

scholarly journals Fluorescent Artificial Receptor-Based Membrane Assay (FARMA) for Spatiotemporally Resolved Monitoring of Biomembrane Permeability

2019 ◽  
Author(s):  
Frank Biedermann ◽  
Garima Ghale, Ghale ◽  
Andreas Hennig ◽  
Werner M. Nau
Keyword(s):  
High Throughput Screening ◽  
High Sensitivity ◽  
Point Of View ◽  
Phospholipid Bilayer ◽  
Label Free ◽  
Microscopy Imaging ◽  
Biophysical Models ◽  
Fundamental Point ◽  
Artificial Receptor ◽  
Microplate Reader

<p>The spatiotemporally resolved monitoring of membrane translocation, <i>e.g.,</i> of drugs or toxins, has been a long-standing goal. Herein, we introduce the fluorescent artificial receptor-based membrane assay (FARMA), a facile, label-free method. With FARMA, the permeation of more than hundred organic compounds (drugs, toxins, pesticides, neurotransmitters, peptides, etc.) through vesicular phospholipid bilayer membranes has been monitored in real time (µs-h time scale) and with high sensitivity (nM-µM concentration), affording permeability coefficients across an exceptionally large range from 10<sup>–9</sup>‑10<sup>–3</sup> cm s<sup>–1</sup>. From a fundamental point of view, FARMA constitutes a powerful tool to assess structure-permeability relationships and to test biophysical models for membrane passage. From an applied perspective, FARMA can be extended to high-throughput screening by adaption of the microplate reader format, to spatial monitoring of membrane permeation by microscopy imaging, and to the compartmentalized monitoring of enzymatic activity.<b></b></p>

scholarly journals EVALUATION OF MODEL RECOGNITION FOR GRAMMAR-BASED AUTOMATIC 3D BUILDING MODEL RECONSTRUCTION

2016 ◽  
Vol XLI-B4 ◽  
pp. 63-69
Author(s):  
Qian Yu ◽  
Petra Helmholz ◽  
David Belton
Keyword(s):  
Laser Scanning ◽  
Quality Evaluation ◽  
Evaluation Process ◽  
3D Models ◽  
Point Of View ◽  
Three Dimensions ◽  
Public And Private ◽  
Building Models ◽  
Evaluation Point ◽  
Increasing Demand

In recent years, 3D city models are in high demand by many public and private organisations, and the steadily growing capacity in both quality and quantity are increasing demand. The quality evaluation of these 3D models is a relevant issue both from the scientific and practical points of view. In this paper, we present a method for the quality evaluation of 3D building models which are reconstructed automatically from terrestrial laser scanning (TLS) data based on an attributed building grammar. The entire evaluation process has been performed in all the three dimensions in terms of completeness and correctness of the reconstruction. Six quality measures are introduced to apply on four datasets of reconstructed building models in order to describe the quality of the automatic reconstruction, and also are assessed on their validity from the evaluation point of view.

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