scholarly journals Characterization of measurement errors using structure-from-motion and photogrammetry to measure marine habitat structural complexity

2017 ◽  
Vol 7 (15) ◽  
pp. 5669-5681 ◽  
Author(s):  
Mitch Bryson ◽  
Renata Ferrari ◽  
Will Figueira ◽  
Oscar Pizarro ◽  
Josh Madin ◽  
...  
2020 ◽  
Vol 75 (11) ◽  
pp. 913-919
Author(s):  
Frank Krumeich

AbstractSince the 1970s, high-resolution transmission electron microscopy (HRTEM) is well established as the most appropriate method to explore the structural complexity of niobium tungsten oxides. Today, scanning transmission electron microscopy (STEM) represents an important alternative for performing the structural characterization of such oxides. STEM images recorded with a high-angle annular dark field (HAADF) detector provide not only information about the cation positions but also about the distribution of niobium and tungsten as the intensity is directly correlated to the local scattering potential. The applicability of this method is demonstrated here for the characterization of the real structure of Nb7W10O47.5. This sample contains well-ordered domains of Nb8W9O47 and Nb4W7O31 besides little ordered areas according to HRTEM results. Structural models for Nb4W7O31 and twinning occurring in this phase have been derived from the interpretation of HAADF-STEM images. A remarkable grain boundary between well-ordered domains of Nb4W7O31 and Nb8W9O47 has been found that contains one-dimensionally periodic features. Furthermore, short-range order observed in less ordered areas could be attributed to an intimate intergrowth of small sections of different tetragonal tungsten bronze (TTB) based structures.


Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4774
Author(s):  
Eric E. Simanek

For two decades, methods for the synthesis and characterization of dendrimers based on [1,3,5]-triazine have been advanced by the group. Motivated by the desire to generate structural complexity on the periphery, initial efforts focused on convergent syntheses, which yielded pure materials to generation three. To obtain larger generations of dendrimers, divergent strategies were pursued using iterative reactions of monomers, sequential additions of triazine and diamines, and ultimately, macromonomers. Strategies for the incorporation of bioactive molecules using non-covalent and covalent strategies have been explored. These bioactive materials included small molecule drugs, peptides, and genetic material. In some cases, these constructs were examined in both in vitro and in vivo models with a focus on targeting prostate tumor subtypes with paclitaxel conjugates. In the materials realm, the use of triazine dendrimers anchored on solid surfaces including smectite clay, silica, mesoporous alumina, polystyrene, and others was explored for the separation of volatile organics from gas streams or the sequestration of atrazine from solution. The combination of these organics with metal nanoparticles has been probed. The goal of this review is to summarize these efforts.


Author(s):  
Frédéric Cointault ◽  
Simeng Han ◽  
Gilles Rabatel ◽  
Sylvain Jay ◽  
David Rousseau ◽  
...  

The development of the concepts of precision agriculture and viticulture since the last three decades has shown the need to use first 2D image acquisition techniques and dedicated image processing. More and more needs concern now 3D images and information. The main ideas of this chapter is thus to present some innovations of the 3D tools and methods in the agronomic domain. This chapter will particularly focus on two main subjects such as the 3D characterization of crop using Shape from Focus or Structure from Motion techniques and the 3D use for root phenotyping using rhizotron system. Results presented show that 3D information allows to better characterize crucial crop morphometric parameters using proxy-detection or phenotyping methods.


Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2364 ◽  
Author(s):  
Martina Cignetti ◽  
Danilo Godone ◽  
Aleksandra Wrzesniak ◽  
Daniele Giordan

Structure from Motion (SfM) is a powerful tool to provide 3D point clouds from a sequence of images taken from different remote sensing technologies. The use of this approach for processing images captured from both Remotely Piloted Aerial Vehicles (RPAS), historical aerial photograms, and smartphones, constitutes a valuable solution for the identification and characterization of active landslides. We applied SfM to process all the acquired and available images for the study of the Champlas du Col landslide, a complex slope instability reactivated in spring 2018 in the Piemonte Region (north-western Italy). This last reactivation of the slide, principally due to snow melting at the end of the winter season, interrupted the main road used to reach Sestriere, one of the most famous ski resorts in north-western Italy. We tested how SfM can be applied to process high-resolution multisource datasets by processing: (i) historical aerial photograms collected from five diverse regional flights, (ii) RGB and multi-spectral images acquired by two RPAS, taken in different moments, and (iii) terrestrial sequences of the most representative kinematic elements due to the evolution of the landslide. In addition, we obtained an overall framework of the historical development of the area of interest, and distinguished several generations of landslides. Moreover, an in-depth geomorphological characterization of the Champlas du Col landslide reactivation was done, by testing a cost-effective and rapid methodology based on SfM principles, which is easily repeatable to characterize and investigate active landslides.


2007 ◽  
Vol 85 (10) ◽  
pp. 889-897 ◽  
Author(s):  
Linus M Perander ◽  
Zoran D Zujovic ◽  
Tania Groutso ◽  
Margaret M Hyland ◽  
Mark E Smith ◽  
...  

The structure of metallurgical- or smelter-grade aluminas (MGAs) is complex and poorly understood. Ultra-high-field solid-state 27Al NMR results on industrial as well as on laboratory-prepared aluminas are discussed in relation to XRD results. It is demonstrated that high-field NMR can effectively be used to quantify the proportion of the thermodynamically stable alpha-alumina phase in these materials. The results demonstrate that 27Al NMR is a vital adjunct to XRD methods to quantify the transition alumina phases that invariably dominate the MGAs. The nature of the disorder in these materials, determined by 27Al NMR, is also compared with literature data, such as XANES and EXAFS studies, on typical laboratory-prepared materials. The utility of 27Al NMR studies to provide new insight into the structural complexity of metallurgical aluminas is shown.Key words: solid-state magic-angle-spinning NMR, metallurgical-grade alumina, transition alumina, gamma-alumina, coordination number.


1982 ◽  
Vol 26 ◽  
pp. 11-24 ◽  
Author(s):  
Allan Brown

Different procedures used in precision measurements of lattice parameters are, strictly, only valid if they can be shown to give results that are mutually reproducible. For this purpose reproducibility is defined in terms of the parameters a. and standard deviations a. obtained for X-ray specimens of one or more reference materials. The requirement is that all systematic errors should be minimized to a level below that of the random measurement errors. Where these have a Gaussian distribution the significance of the difference, Δa°, between two , measurements can then be Let;Led by evaluating . Thus, if K < 2 the difference, Δa°, cannot be distinguished from the effects of random measurement errors. This condition should be met for specimens of the same sample if reproducibility is good. For K ≥ 3 the value of Δa° is then taken to reflect real differences in the crystalline Jattice of two X-ray specimens of a given compound. A basis is thus created for the study of solid solubility and for the precise characterization of crystalline compounds.


Mathematics ◽  
2021 ◽  
Vol 9 (17) ◽  
pp. 2116
Author(s):  
Miguel A. Sainz ◽  
Remei Calm ◽  
Lambert Jorba ◽  
Ivan Contreras ◽  
Josep Vehi

The system of marks created by Dr. Ernest Gardenyes and Dr. Lambert Jorba was first published as a doctoral thesis in 2003 and then as a chapter in the book Modal Interval Analysis in 2014. Marks are presented as a tool to deal with uncertainties in physical quantities from measurements or calculations. When working with iterative processes, the slow convergence or the high number of simulation steps means that measurement errors and successive calculation errors can lead to a lack of significance in the results. In the system of marks, the validity of any computation results is explicit in their calculation. Thus, the mark acts as a safeguard, warning of such situations. Despite the obvious contribution that marks can make in the simulation, identification, and control of dynamical systems, some improvements are necessary for their practical application. This paper aims to present these improvements. In particular, a new, more efficient characterization of the difference operator and a new implementation of the marks library is presented. Examples in dynamical systems simulation, fault detection and control are also included to exemplify the practical use of the marks.


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