scholarly journals Uso del procesamiento digital de imágenes para la extracción de datos de medidas experimentales publicados en formato gráfico

Author(s):  
Edebaldo Peza-Ortiz ◽  
José Bernardo Torres-Valle ◽  
Enrique García-Trinidad ◽  
Alma Delia González Ramos-Gora

In this article, we propose a method as an alternative to obtain experimental measurement data, in the absence of laboratory equipment to perform tests, in a suitable format to perform mathematical operations in order to use them as information to validate: hypotheses, models constitutive and / or research theories focused on technological development. The proposed method uses as a main tool the image segmentation technique by region growth by pixel grouping and the normalization of the coordinates of the positions of the pixels extracted to the axis scale in the corresponding figure. The segmentation of the image separates the coordinates of the pixels that form the axes and the curves, the coordinates of the pixels of the curves are normalized to the scale of the axes. The method is tested with images of the result of experimental tests of stress-strain behavior recovered from [1]. The results of the data extraction are plotted and the averages of each curve extracted as well as the standard deviation are obtained. It is verified that the data obtained can be used to corroborate or support hypotheses in a wide range of investigations.

Author(s):  
Edebaldo Peza Ortiz ◽  
José Bernardo Torres Valle ◽  
Enrique García Trinidad ◽  
Alma Delia González Ramos Gora

In this article, we propose a method as an alternative to obtain experimental measurement data, in the absence of laboratory equipment to perform tests, in a suitable format to perform mathematical operations in order to use them as information to validate: hypotheses, models constitutive and / or research theories focused on technological development. The proposed method uses as a main tool the image segmentation technique by region growth by pixel grouping and the normalization of the coordinates of the positions of the pixels extracted to the axis scale in the corresponding figure. The segmentation of the image separates the coordinates of the pixels that form the axes and the curves, the coordinates of the pixels of the curves are normalized to the scale of the axes. The method is tested with images of the result of experimental tests of stress-strain behavior recovered from [1]. The results of the data extraction are plotted and the averages of each curve extracted as well as the standard deviation are obtained. It is verified that the data obtained can be used to corroborate or support hypotheses in a wide range of investigations.


Author(s):  
Giuseppe Catania ◽  
Nicolo` Mancinelli

This study refers to the investigation on the critical operating condition occurring on high productivity milling machines, known as chatter. This phenomenon is generated by a self-excited vibration, associated with a loss of stability of the system, causing reduced productivity, poor surface finish and noise. This study consists of the theoretical and experimental modeling of machining chatter conditions, in order to develop a real-time monitoring system able to diagnose the occurrence of chatter in advance and to dynamically modify the cutting parameters for process optimization. A prototype NC 3-axis milling machine was ad hoc realized to accomplish this task. The machine was instrumented by a dynamometer table, and a series of accelerometer sensors were mounted in the proximity of the tool spindle and the workpiece. An analytical model was developed, taking into account the periodic cutting force arising during interrupted cutting operation in milling. The system dynamical behavior was described by means of a set of delay differential equations with periodic coefficients. The stability of this system was analyzed by the semi discretization approach based on the Floquet theory. Lobe stability charts were evaluated and associated with frequency diagrams. Two chatter types were analytically and experimentally detected: period-doubling bifurcations and secondary Hopf bifurcations. Measurement data were acquired and analyzed in the time and frequency domain. Several tests were conducted in a wide range of operating conditions, such as radial immersion, depth of cut and spindle speeds and using different tools. Results are reported showing agreement between the numerical analysis and the related experimental tests.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Eleanor F. Miller ◽  
Andrea Manica

Abstract Background Today an unprecedented amount of genetic sequence data is stored in publicly available repositories. For decades now, mitochondrial DNA (mtDNA) has been the workhorse of genetic studies, and as a result, there is a large volume of mtDNA data available in these repositories for a wide range of species. Indeed, whilst whole genome sequencing is an exciting prospect for the future, for most non-model organisms’ classical markers such as mtDNA remain widely used. By compiling existing data from multiple original studies, it is possible to build powerful new datasets capable of exploring many questions in ecology, evolution and conservation biology. One key question that these data can help inform is what happened in a species’ demographic past. However, compiling data in this manner is not trivial, there are many complexities associated with data extraction, data quality and data handling. Results Here we present the mtDNAcombine package, a collection of tools developed to manage some of the major decisions associated with handling multi-study sequence data with a particular focus on preparing sequence data for Bayesian skyline plot demographic reconstructions. Conclusions There is now more genetic information available than ever before and large meta-data sets offer great opportunities to explore new and exciting avenues of research. However, compiling multi-study datasets still remains a technically challenging prospect. The mtDNAcombine package provides a pipeline to streamline the process of downloading, curating, and analysing sequence data, guiding the process of compiling data sets from the online database GenBank.


Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1537
Author(s):  
Aneta Saletnik ◽  
Bogdan Saletnik ◽  
Czesław Puchalski

Raman spectroscopy is one of the main analytical techniques used in optical metrology. It is a vibration, marker-free technique that provides insight into the structure and composition of tissues and cells at the molecular level. Raman spectroscopy is an outstanding material identification technique. It provides spatial information of vibrations from complex biological samples which renders it a very accurate tool for the analysis of highly complex plant tissues. Raman spectra can be used as a fingerprint tool for a very wide range of compounds. Raman spectroscopy enables all the polymers that build the cell walls of plants to be tracked simultaneously; it facilitates the analysis of both the molecular composition and the molecular structure of cell walls. Due to its high sensitivity to even minute structural changes, this method is used for comparative tests. The introduction of new and improved Raman techniques by scientists as well as the constant technological development of the apparatus has resulted in an increased importance of Raman spectroscopy in the discovery and defining of tissues and the processes taking place in them.


2016 ◽  
Vol 113 (15) ◽  
pp. 3932-3937 ◽  
Author(s):  
Steven L. Brunton ◽  
Joshua L. Proctor ◽  
J. Nathan Kutz

Extracting governing equations from data is a central challenge in many diverse areas of science and engineering. Data are abundant whereas models often remain elusive, as in climate science, neuroscience, ecology, finance, and epidemiology, to name only a few examples. In this work, we combine sparsity-promoting techniques and machine learning with nonlinear dynamical systems to discover governing equations from noisy measurement data. The only assumption about the structure of the model is that there are only a few important terms that govern the dynamics, so that the equations are sparse in the space of possible functions; this assumption holds for many physical systems in an appropriate basis. In particular, we use sparse regression to determine the fewest terms in the dynamic governing equations required to accurately represent the data. This results in parsimonious models that balance accuracy with model complexity to avoid overfitting. We demonstrate the algorithm on a wide range of problems, from simple canonical systems, including linear and nonlinear oscillators and the chaotic Lorenz system, to the fluid vortex shedding behind an obstacle. The fluid example illustrates the ability of this method to discover the underlying dynamics of a system that took experts in the community nearly 30 years to resolve. We also show that this method generalizes to parameterized systems and systems that are time-varying or have external forcing.


Author(s):  
Mirko Baratta ◽  
Stefano d’Ambrosio ◽  
Daniela Misul ◽  
Ezio Spessa

An experimental investigation and a burning-rate analysis have been performed on a production 1.4 liter CNG (compressed natural gas) engine fueled with methane-hydrogen blends. The engine features a pent-roof combustion chamber, four valves per cylinder and a centrally located spark plug. The experimental tests have been carried out in order to quantify the cycle-to-cycle and the cylinder-to-cylinder combustion variation. Therefore, the engine has been equipped with four dedicated piezoelectric pressure transducers placed on each cylinder and located by the spark plug. At each test point, in-cylinder pressure, fuel consumption, induced air mass flow rate, pressure and temperature at different locations on the engine intake and exhaust systems as well as ‘engine-out’ pollutant emissions have been measured. The signals correlated to the engine operation have been acquired by means of a National Instruments PXI-DAQ system and a home developed software. The acquired data have then been processed through a combustion diagnostic tool resulting from the integration of an original multizone thermodynamic model with a CAD procedure for the evaluation of the burned-gas front geometry. The diagnostic tool allows the burning velocities to be computed. The tests have been performed over a wide range of engine speeds, loads and relative air-fuel ratios (up to the lean operation). For stoichiometric operation, the addition of hydrogen to CNG has produced a bsfc reduction ranging between 2 to 7% and a bsTHC decrease up to the 40%. These benefits have appeared to be even higher for lean mixtures. Moreover, hydrogen has shown to significantly enhance the combustion process, thus leading to a sensibly lower cycle-to-cycle variability. As a matter of fact, hydrogen addition has generally resulted into extended operation up to RAFR = 1.8. Still, a discrepancy in the abovementioned conclusions was observed depending on the engine cylinder considered.


Separations ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 13
Author(s):  
Petra Ranušová ◽  
Ildikó Matušíková ◽  
Peter Nemeček

A solid-phase extraction (SPE) procedure was developed for simultaneous monitoring of sixteen different phenolics of various polarity, quantified by high-performance liquid chromatography (HPLC). The procedure allowed screening the accumulation of intermediates in different metabolic pathways that play a crucial role in plant physiology and/or are beneficial for human health. Metabolites mostly involved in phenylpropanoid, shikimate, and polyketide pathways comprise chlorogenic acid, gentisic acid, vanillic acid, caffeic acid, protocatechuic acid, ferulic acid, rutin, quercetin, epicatechin, gallic acid, sinapic acid, p-coumaric acid, o-coumaric acid, vanillin; two rarely quantified metabolites, 2,5-dimethoxybenzoic acid and 4-methoxycinnamic acid, were included as well. The procedure offered low cost, good overall efficiency, and applicability in laboratories with standard laboratory equipment. SPE recoveries were up to 99.8% at various concentration levels. The method allowed for routine analysis of compounds with a wide range of polarity within a single run, while its applicability was demonstrated for various model plant species (tobacco, wheat, and soybean), as well as different tissue types (shoots and roots).


2015 ◽  
Vol 4 (2) ◽  
pp. 149-154 ◽  
Author(s):  
A. M. Prystai ◽  
V. O. Pronenko

Abstract. The study of the deep structure of the Earth's crust is of great interest for both applied (e.g. mineral exploration) and scientific research. For this the electromagnetic (EM) studies which enable one to construct the distribution of electrical conductivity in the Earth's crust are of great use. The most common method of EM exploration is magnetotelluric sounding (MT). This passive method of research uses a wide range of natural geomagnetic variations as a powerful source of electromagnetic induction in the Earth, producing telluric current variations there. It includes the measurements of variations of natural electric and magnetic fields in orthogonal directions at the surface of the Earth. By this, the measurements of electric fields are much more complicated metrological processes, and, namely, they limit the precision of MT prospecting. This is especially complicated at deep sounding when measurements of long periods are of interest. The increase in the accuracy of the electric field measurement can significantly improve the quality of MT data. Because of this, the development of a new version of an instrument for the measurements of electric fields at MT – both electric field sensors and the electrometer – with higher levels relative to the known instrument parameter level – was initiated. The paper deals with the peculiarities of this development and the results of experimental tests of the new sensors and electrometers included as a unit in the long-period magnetotelluric station LEMI-420 are given.


2018 ◽  
Vol 16 (4) ◽  
pp. 517-532
Author(s):  
Bex Lewis

Social media has become a part of everyday life, including the faith lives of many. It is a space that assumes an observing gaze. Engaging with Foucauldian notions of surveillance, self-regulation, and normalisation, this paper considers what it is about social and digital culture that shapes expectations of what users can or want to do in online spaces. Drawing upon a wide range of surveillance research, it reflects upon what “surveillance” looks like within social media, especially when users understand themselves to be observed in the space. Recognising moral panics around technological development, the paper considers the development of social norms and questions how self-regulation by users presents itself within a global population. Focusing upon the spiritual formation of Christian users (disciples) in an online environment as a case study of a community of practice, the paper draws particularly upon the author’s experiences online since 1997 and material from The Big Bible Project (CODEC 2010–2015). The research demonstrates how the lived experience of the individual establishes the interconnectedness of the online and offline environments. The surveillant affordances and context collapse are liberating for some users but restricting for others in both their faith formation and the subsequent imperative to mission.


Author(s):  
Edward Lock ◽  
Kate Kelly

The widely held view that higher education constitutes a gateway to employment has underpinned the dramatic widening of access to university in recent decades. However, globalisation and technological development have complicated the task of enhancing the employability of students, as the future world of work has become ever-more dynamic and unpredictable. Given such conditions, the delivery of employability teaching has become a central focus of many higher education providers (HEPs). To meet their responsibilities, HEPs must understand how students perceive their respective courses in relation to the employment pathways that they seek to follow. The present study aimed to gain an understanding of prospective students’ perceptions regarding this, but also to evaluate the accuracy of these perceptions. Because some course types are more narrowly vocational than are others, a subsidiary aim was to investigate whether or not student expectations and knowledge varied depending on course-type. The findings gathered from 462 students enrolled into a wide range of courses at 15 Australian universities were profound. They highlight that, while most students commence university with a career goal in mind, many have a poor understanding of the education-employment pathways on which they have embarked. Students demonstrated a limited understanding of the careers to which their courses might lead, and of the relevance of postgraduate study to their chosen career goals. These findings varied significantly across different course-types. Overall, these findings highlight the need for HEPs to educate their students explicitly about the education-employment pathways that are available to them.


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