scholarly journals Metrología óptica en el estudio de eventos dinámicos

2020 ◽  
pp. 9-13
Author(s):  
Yadira Fabiola López-Álvarez / ◽  
Francisco Gerardo Peña-Lecona ◽  
Ricardo Jara-Ruíz ◽  
Sergio Delgado-Guerrero
Keyword(s):  
Physical Properties ◽  
Holographic Interferometry ◽  
Change Point ◽  
Structural Changes ◽  
Rotating System ◽  
Dynamic Event ◽  
Phase Displacement ◽  
Phase Map ◽  
Over Time

The evolution over time of structural changes in materials is of great importance in various areas of science, its study involves determining the phase with the change in the intensity of the physical properties to be measured. In this work, the use of Phase Displacement Interferometry PSI is presented using a combination algorithm of five interferograms or five steps, the results are compared with the addition of the states studied in the dynamic event, exposed in the Digital Holographic Interferometry DHI. The deformation was simulated from a rotating system in the coordinates (x, y). The results suggest that the phase map of the changing events with time that are calculated with PSI of five steps may have a relationship with the average of each change point of the dynamic event, with a difference of 0.96 radians.

scholarly journals Effects of precession versus instabilities on the jets of GRS 1758–258

2020 ◽  
Vol 643 ◽  
pp. A150
Author(s):  
Pedro L. Luque-Escamilla ◽  
Josep Martí ◽  
José Martínez-Aroza
Keyword(s):  
Physical Properties ◽  
Orbital Period ◽  
Large Scale ◽  
Structural Changes ◽  
Morphological Changes ◽  
Secondary Star ◽  
Radio Jets ◽  
New Radio ◽  
Tidal Torques ◽  
Over Time

Aims. The prototypical microquasar GRS 1758–258 exhibits large-scale morphological changes in radio maps over time which have been attributed to the rise of instabilities. Here, we investigate whether these effects could be attributed to jet precession instead. Methods. We used new and archival radio maps to fit a kinematic jet precession model. The value of the parameters thus obtained were analysed in order to get constraints on the physical properties of the GRS 1758–258 system. Their consistency with different theories of the origins for the jet precession, such as Lense–Thirring effect and tidal torques induced by the secondary star, has previously been studied. Alternatively, we also assessed the possibility that observations are compatible with eventual jet instabilities. Results. The new radio data presented here confirm that the large-scale radio morphology of GRS 1758–258 is changing over time. Our study shows that the 18.48 day period could plausibly be ascribed to precession, thus implying a reinterpretation of assumptions made for the orbital period to date. However, the observed structural changes in radio jets cannot be easily attributed to jet precession according to our analysis. In contrast, the growth of instabilities certainly appears to be a more realistic explanation of these effects.

scholarly journals Likelihood-based approach to discriminate mixtures of network models that vary in time

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Naomi A. Arnold ◽  
Raul J. Mondragón ◽  
Richard G. Clegg
Keyword(s):  
Network Model ◽  
Change Point ◽  
Network Science ◽  
Preferential Attachment ◽  
Network Models ◽  
Explanatory Models ◽  
Growth Mechanisms ◽  
Artificial Data ◽  
Network Growth ◽  
Over Time

AbstractDiscriminating between competing explanatory models as to which is more likely responsible for the growth of a network is a problem of fundamental importance for network science. The rules governing this growth are attributed to mechanisms such as preferential attachment and triangle closure, with a wealth of explanatory models based on these. These models are deliberately simple, commonly with the network growing according to a constant mechanism for its lifetime, to allow for analytical results. We use a likelihood-based framework on artificial data where the network model changes at a known point in time and demonstrate that we can recover the change point from analysis of the network. We then use real datasets and demonstrate how our framework can show the changing importance of network growth mechanisms over time.

Bayesian and profile likelihood change point methods for modeling cognitive function over time

2003 ◽  
Vol 42 (1-2) ◽  
pp. 91-109 ◽  
Author(s):  
Charles B. Hall ◽  
Jun Ying ◽  
Lynn Kuo ◽  
Richard B. Lipton
Keyword(s):  
Cognitive Function ◽  
Change Point ◽  
Profile Likelihood ◽  
Over Time

scholarly journals Detailed Quantification of Glomerular Structural Lesions Associates with Clinical Outcomes and Transcriptomic Profiles in Nephrotic Syndrome

2021 ◽  
Author(s):  
Jeffrey B. Hodgin ◽  
Laura H. Mariani ◽  
Jarcy Zee ◽  
Q Liu ◽  
Abigail R. Smith ◽  
...  
Keyword(s):  
Nephrotic Syndrome ◽  
Disease Progression ◽  
Clinical Outcomes ◽  
Messenger Rna ◽  
Structural Changes ◽  
Classification Systems ◽  
Molecular Heterogeneity ◽  
Biologically Relevant ◽  
Current Classification ◽  
Over Time

ABSTRACTThe current classification system for focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) does not fully capture the complex structural changes in kidney biopsies, nor the clinical and molecular heterogeneity of these diseases. The Nephrotic Syndrome Study Network (NEPTUNE) Digital Pathology Scoring System (NDPSS) was applied to 221 NEPTUNE FSGS/MCD digital kidney biopsies for glomerular scoring using 37 descriptors. The descriptor-based glomerular profiles were used to cluster patients with similar morphologic characteristics. Glomerular descriptors and patient clusters were assessed for association with time to proteinuria remission and disease progression by using adjusted Cox models, and eGFR measures over time by using linear mixed models. Messenger RNA from glomerular tissue was used to assess differentially expressed genes (DEG) between clusters and identify genes associated with individual descriptors driving cluster membership. Three clusters were identified: X (N=56), Y (N=68), and Z (N=97). Clusters Y and Z had higher probabilities of proteinuria remission (HR [95% CI]= 1.95 [0.99, 3.85] and 3.29 [1.52, 7.13], respectively), lower hazards of disease progression 0.22 [0.08, 0.57] and 0.11 [0.03, 0.45], respectively), and greater loss of eGFR over time compared with X. Cluster X had 1920 DEGs compared to Y+Z, which reflected activation of pathways of immune response and inflammation. Six individual descriptors driving the clusters individually correlated with clinical outcomes and gene expression. The NDPSS allows for characterization of FSGS/MCD patients into clinically and biologically relevant categories and uncovers histologic parameters associated with clinical outcomes and molecular signatures not included in current classification systems.TRANSLATIONAL STATEMENTFSGS and MCD are heterogeneous diseases that manifest with a variety of structural changes often not captured by conventional classification systems. This study shows that a detailed morphologic analysis and quantification of these changes allows for better representation of the structural abnormalities within each patient and for grouping patients with similar morphologic profiles into categories that are clinically and biologically relevant.

scholarly journals A study into the structure and physical properties of the Cr18Ni9-grade steel following long-term irradiation as part of the BN-600 reactor internals

2020 ◽  
Vol 6 (1) ◽  
pp. 1-6
Author(s):  
Irina A. Portnykh ◽  
Aleksandr V. Kozlov ◽  
Valery L. Panchenko ◽  
Vyacheslav S. Shikhalev
Keyword(s):  
Physical Properties ◽  
Young’S Modulus ◽  
Structural Changes ◽  
Young's Modulus ◽  
Void Size ◽  
Initial State ◽  
Porosity Distribution ◽  
Grade Steel ◽  
Reactor Internals

The microstructures and physical properties of the austenitic Cr18Ni9-grade steel after 22 and 33 years of operation as part of the reactor internals were tested for assessing the conditions of the BN-600 reactor non-replaceable components (internals) and the potential of their subsequent use in predicting the reactor ultimate life. The paper presents histograms of the porosity distribution depending on the void size, in samples taken from portions that were subjected to neutron irradiation with displacement rates ranging from 1.0×10–9 to 4.3×10–8 dpa/s at temperatures from 370 to 440 °C. The elasticity characteristics were measured by resonance-type ultrasonic technique for the samples taken from the same portions of material. It was demonstrated that swelling calculated using the histograms of the porosity distribution depending on the void size has the maximum value at ~415 °C and after 33 years of irradiation reaches values of ~3%. Long-term variations of Young’s modulus demonstrate non-monotonous dependence on the damage dose. The maximum relative variation of Young’s modulus after 22 and 33 years of operation does not exceed 2% and 6%, respectively, of the values corresponding to the initial state. It was shown that along with the irradiation-induced swelling the changes in the physical properties are also affected in the process of irradiation by other structural changes and, in particular, by the formation of secondary phases. As shown by the results of the studies, operation of the BN-600 reactor internals made of Cr18Ni9-grade steel can be extended beyond 33 years of service. The comparison of the results obtained for the material after 22 and 33 years of operation contains information required for describing subsequent changes of the structure and properties of the Cr18Ni9 internals. The obtained results can be used for forecasting the reactor ultimate life within the framework of existing and developed models.

scholarly journals Physical Properties and Non-Isothermal Crystallisation Kinetics of Primary Mechanically Recycled Poly(l-lactic acid) and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3396
Author(s):  
Luboš Běhálek ◽  
Jan Novák ◽  
Pavel Brdlík ◽  
Martin Borůvka ◽  
Jiří Habr ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Physical Properties ◽  
Structural Changes ◽  
The Other ◽  
Half Time ◽  
Crystallisation Kinetics ◽  
Isothermal Crystallisation ◽  
Melt Crystallisation ◽  
Kinetics Of ◽  
Crystallisation Rate

The physical properties and non-isothermal melt- and cold-crystallisation kinetics of poly (l-lactic acid) (PLLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) biobased polymers reprocessed by mechanical milling of moulded specimens and followed injection moulding with up to seven recycling cycles are investigated. Non-isothermal crystallisation kinetics are evaluated by the half-time of crystallisation and a procedure based on the mathematical treatment of DSC cumulative crystallisation curves at their inflection point (Kratochvil-Kelnar method). Thermomechanical recycling of PLLA raised structural changes that resulted in an increase in melt flow properties by up to six times, a decrease in the thermal stability by up to 80 °C, a reduction in the melt half-time crystallisation by up to about 40%, an increase in the melt crystallisation start temperature, and an increase in the maximum melt crystallisation rate (up to 2.7 times). Furthermore, reprocessing after the first recycling cycle caused the elimination of cold crystallisation when cooling at a slow rate. These structural changes also lowered the cold crystallisation temperature without impacting the maximum cold crystallisation rate. The structural changes of reprocessed PHBV had no significant effect on the non-isothermal crystallisation kinetics of this material. Additionally, the thermomechanical behaviour of reprocessed PHBV indicates that the technological waste of this biopolymer is suitable for recycling as a reusable additive to the virgin polymer matrix. In the case of reprocessed PLLA, on the other hand, a significant decrease in tensile and flexural strength (by 22% and 46%, respectively) was detected, which reflected changes within the biobased polymer structure. Apart from the elastic modulus, all the other thermomechanical properties of PLLA dropped down with an increasing level of recycling.

scholarly journals Variation of Physical Properties of Cement over Time

2018 ◽  
Vol 10 (6) ◽  
pp. 434-439
Author(s):  
Riazul Haque ◽  
◽  
Sumit Purkayastha ◽  
Abdul Muktadir Khan
Keyword(s):  
Physical Properties ◽  
Over Time

Structural changes over time in individual‐based networks involving a harvester ant, seeds, and invertebrates

2019 ◽  
Vol 44 (6) ◽  
pp. 753-761 ◽  
Author(s):  
Diego V. Anjos ◽  
Pedro Luna ◽  
Carla C. R. Borges ◽  
Wesley Dáttilo ◽  
Kleber Del‐Claro
Keyword(s):  
Structural Changes ◽  
Harvester Ant ◽  
Changes Over Time ◽  
Over Time

Mechanical and Basic Physical Properties of High-Strength Concrete Exposed to Elevated Temperatures

2018 ◽  
Vol 760 ◽  
pp. 108-113 ◽  
Author(s):  
Lenka Scheinherrová ◽  
Monika Čáchová ◽  
Michaela Petříková ◽  
Lukáš Fiala ◽  
Eva Vejmelková ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Physical Properties ◽  
Structural Changes ◽  
Elevated Temperatures ◽  
Water Environment ◽  
High Strength ◽  
Steel Fibers ◽  
Quartz Powder ◽  
Matrix Density ◽  
Drying Treatment

In this paper, the effect of elevated temperatures on the mechanical and basic properties of two different newly-designed high-strength concretes is studied. The studied materials were prepared from Portland cement, steel fibers, reactive finely milled quartz powder and quartz sand, silica fume, plasticizer, and with a relatively low water/cement ratio of 0.24. The samples were stored in water environment for the first 28 days of hydration to achieve better mechanical properties. Then, after pre-drying at 105 °C to constant mass, the materials were exposed to elevated temperatures of 600 °C and 1000 °C where they were kept for 2 hours. The basic physical properties, such as matrix density, bulk density and open porosity were determined as a function of temperature. Mechanical properties (compressive and flexural strength) were also studied. The measured parameters exhibited a high dependence on temperature and the obtained results pointed to the structural changes of the studied materials. Spalling was not observed because of the pre-drying treatment.

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