scholarly journals Application of holography and automated image processing for laboratory experiments on mass and fall speed of small cloud ice crystals

2020 ◽  
Author(s):  
Maximilian Weitzel ◽  
Subir K. Mitra ◽  
Miklós Szakáll ◽  
Jacob P. Fugal ◽  
Stephan Borrmann

Abstract. An ice cloud chamber was developed at the Johannes Gutenberg University of Mainz for generating several thousand data points for mass and sedimentation velocity measurements of ice crystals with sizes less than 150 μm. Ice nucleation was initiated from a cloud of supercooled droplets by local cooling using a liquid nitrogen cold finger. Three-dimensional tracks of ice crystals falling through the slightly supersaturated environment were obtained from the reconstruction of sequential holographic images, automated detection of the crystals in the hologram reconstructions, and particle tracking. Through collection of the crystals and investigation under a microscope before and after melting, crystal mass was determined as a function of size. The experimentally obtained mass versus diameter (m(D)) power law relationship resulted in lower masses for small ice crystals than from commonly adopted parameterizations. Thus, they did not support the currently accepted extrapolation of relationships measured for larger crystal sizes. The relationship between Best (X) and Reynolds (Re) numbers for columnar crystals was found to be X = 15.3Re1.2, which is in general agreement with literature parameterizations.

2020 ◽  
Vol 20 (23) ◽  
pp. 14889-14901
Author(s):  
Maximilian Weitzel ◽  
Subir K. Mitra ◽  
Miklós Szakáll ◽  
Jacob P. Fugal ◽  
Stephan Borrmann

Abstract. An ice cloud chamber was developed at the Johannes Gutenberg University of Mainz for generating several thousand data points for mass and sedimentation velocity measurements of ice crystals with sizes less than 150 µm. Ice nucleation was initiated from a cloud of supercooled droplets by local cooling using a liquid nitrogen cold finger. Three-dimensional tracks of ice crystals falling through the slightly supersaturated environment were obtained from the reconstruction of sequential holographic images, automated detection of the crystals in the hologram reconstructions, and particle tracking. Through collection of the crystals and investigation under a microscope before and after melting, crystal mass was determined as a function of size. The experimentally obtained mass versus diameter (m(D)) power law relationship resulted in lower masses for small ice crystals than from commonly adopted parameterizations. Thus, they did not support the currently accepted extrapolation of relationships measured for larger crystal sizes. The relationship between Best (X) and Reynolds (Re) numbers for columnar crystals was found to be X=15.3 Re1.2, which is in general agreement with literature parameterizations.


Author(s):  
Karen Perta ◽  
Eileen Kalmar ◽  
Youkyung Bae

Purpose The aim of the study was to update our information regarding the salpingopharyngeus (SP) muscle using cadaveric and in vivo magnetic resonance imaging (MRI) data. Primary objectives were to (a) observe the presence/absence of the muscle and (b) quantify and describe its dimensions and course. Method SP specimens from 19 cadavers (10 women, nine men) were analyzed. Following head bisection, measurements of SP, including width of the cartilaginous attachment (CW) and width of the superior muscle base (SMW), were taken before and after removal of the overlying mucosa. In addition, SP was analyzed in 15 healthy subjects (eight men, seven women) using high-resolution three-dimensional MRI data. CW and SMW measures were replicated in the paraxial MRI view. Results The presence of the salpingopharyngeal fold and muscle was confirmed bilaterally in all cadaveric and living subjects. Following mucosa removal, mean cadaveric CW and SMW measurements were 5.6 and 3.8 mm, respectively. Mean in vivo CW and SMW were 6.1 and 3.7 mm, respectively. Results from the hierarchical regression analyses revealed that, in both cadaveric and living groups, SMW is dependent on the relationship between age and body weight, after controlling for sex. Conclusions The salpingopharyngeal fold and SP muscle are always present bilaterally and can be quantified at the superior origin using both cadaveric and in vivo three-dimensional MRI data. Though both the superior origin and inferior course of SP are highly variable, the size of the SP muscle is dependent on characteristics known to affect muscle fibers, such as the relationship between age and body weight. Given the consistent and quantifiable presence of the SP muscle, its potential role in velopharyngeal function for speech and swallowing is reconsidered. Supplemental Material https://doi.org/10.23641/asha.14347859


Geophysics ◽  
1978 ◽  
Vol 43 (6) ◽  
pp. 1274-1275
Author(s):  
V. Courtillot ◽  
J. Ducruix ◽  
J. L. Le Mouël

In their paper, Bhattacharryya and Chan address the problem of reduction of magnetic and gravity data on an arbitrary surface acquired in a region of high topographic relief. In their work, the authors are kind enough to mention our contribution to the solution of the problem of finding the sources responsible for an observed magnetic or gravity anomaly, using the general formalism of inverse problems (Courtillot et al, 1974). Unfortunately, however, the authors seem to be unaware of our other publications which are far more relevant to their subject. Courtillot et al (1973) solved the problem of continuation of a potential field measured on an uneven profile, using the Backus and Gilbert approach. Another reference relevant to this problem (solved by Bhattacharryya and Chan on p. 1424) is Parker and Klitgord (1972), who used the Schwartz‐Christoffel transformation. The work was extended to the case of three‐dimensional potential fields measured on an uneven surface by Ducruix et al (1974). Indeed, the development of our paper is strikingly similar to that of Bhattacharryya and Chan, although the method is quite different. In our paper, we give many illustrations of both theoretical and real cases, in which our method is seen to perform very well. We leave it to the reader to compare the results provided by both methods and to compare the methods themselves. In a third paper (Le Mouël et al, 1975), we generalized the method and showed how one could obtain excellent approximate analytic solutions of the Dirichlet and Neumann problems in the two‐dimensional case for a contour with any arbitrary shape. Finally, let us take the opportunity of this discussion to mention a review of the subject which appears in French in Courtillot (1977) and in English, much expanded, in Courtillot et al (1978). In this last paper, which should be of interest in solving a variety of geophysical problems, we show how our method allows one to continue a potential field measured on an entirely arbitrary set of data points in any number of dimensions for the various coordinate systems in which the Laplace and Helmholtz equations are separable. We also establish the relationship between our method and a generalization of the theory of generalized inverse matrices. One other relevant reference on that subject is Parker (1977). In the case of spherical coordinates, an application can be the continuation of satellite data, a problem studied by Bhattacharryya (1977).


2018 ◽  
Vol 88 (2) ◽  
pp. 187-194 ◽  
Author(s):  
Jae Hyun Park ◽  
Sungkon Kim ◽  
Yoon-Jin Lee ◽  
Mohamed Bayome ◽  
Yoon-Ah Kook ◽  
...  

ABSTRACT Objectives: To evaluate the changes in position of the maxillary dentition and the airway space after distalization using a modified C-palatal plate (MCPP) in adult patients through CBCT images and to analyze the relationship between the amount of distalization and the changes in the airway space. Materials and Methods: CBCT images of 33 adult Class II patients (22.2 ± 4.0 years old; 27 women and 6 men) treated by total maxillary arch distalization using the MCPP were evaluated before and after distalization. The patients were divided into nonextraction and extraction groups. The changes in the airway space as well as the changes in the positions of the maxillary dentition were evaluated. The distalization effects were calculated and assessed using paired t-tests. Results: After distalization, the first molar showed significant distalization and intrusion (P < .001) with no significant rotation of the crown and no significant buccal displacement of its root in the transverse dimension. There were no significant changes in the airway volume or the minimum cross-sectional area of the oropharynx. Conclusions: The application of the MCPP resulted in significant total arch distalization without a significant effect on the transverse dimensions or changes in the oropharynx airway space. The MCPP can be considered a viable treatment option for patients with Class II malocclusion.


2018 ◽  
Vol 11 (10) ◽  
pp. 4269-4289 ◽  
Author(s):  
Thomas Hoarau ◽  
Jean-Pierre Pinty ◽  
Christelle Barthe

Abstract. The paper describes a switchable parameterization of collisional ice break-up (CIBU), an ice multiplication process that fits in with the two-moment microphysical Liquid Ice Multiple Aerosols (LIMA) scheme. The LIMA scheme with three ice types (pristine cloud ice crystals, snow aggregates, and graupel hail) was developed in the cloud-resolving mesoscale model (Meso-NH). Here, the CIBU parameterization assumes that collisional break-up is mostly efficient for the small and fragile snow aggregate class of particles when they are hit by large, dense graupel particles. The increase of cloud ice number concentration depends on a prescribed number (or a random number) of fragments being produced per collision. This point is discussed and analytical expressions of the newly contributing CIBU terms in LIMA are given. The scheme is run in the cloud-resolving mesoscale model (Meso-NH) to simulate a first case of a three-dimensional deep convective event with heavy production of graupel. The consequence of dramatically changing the number of fragments produced per collision is investigated by examining the rainfall rates and the changes in small ice concentrations and mass mixing ratios. Many budgets of the ice phase are shown and the sensitivity of CIBU to the initial concentration of freezing nuclei is explored. The scheme is then tested for another deep convective case where, additionally, the convective available potential energy (CAPE) is varied. The results confirm the strong impact of CIBU with up to a 1000-fold increase in small ice concentrations, a reduction of the rainfall or precipitating area, and an invigoration of the convection with higher cloud tops. Finally, it is concluded that the efficiency of the ice crystal fragmentation needs to be tuned carefully. The proposed parameterization of CIBU is easy to implement in any two-moment microphysics scheme. It could be used in this form to simulate deep tropical cloud systems where anomalously high concentrations of small ice crystals are suspected.


2012 ◽  
Vol 33 (2) ◽  
pp. 83-88 ◽  
Author(s):  
David Moreau ◽  
Jérome Clerc ◽  
Annie Mansy-Dannay ◽  
Alain Guerrien

This experiment investigated the relationship between mental rotation and sport training. Undergraduate university students (n = 62) completed the Mental Rotation Test ( Vandenberg & Kuse, 1978 ), before and after a 10-month training in two different sports, which either involved extensive mental rotation ability (wrestling group) or did not (running group). Both groups showed comparable results in the pretest, but the wrestling group outperformed the running group in the posttest. As expected from previous studies, males outperformed women in the pretest and the posttest. Besides, self-reported data gathered after both sessions indicated an increase in adaptive strategies following training in wrestling, but not subsequent to training in running. These findings demonstrate the significant effect of training in particular sports on mental rotation performance, thus showing consistency with the notion of cognitive plasticity induced from motor training involving manipulation of spatial representations. They are discussed within an embodied cognition framework.


2020 ◽  
Vol 22 (3) ◽  
pp. 341-361
Author(s):  
Gonzalo Grau-Pérez ◽  
J. Guillermo Milán

In Uruguay, Lacanian ideas arrived in the 1960s, into a context of Kleinian hegemony. Adopting a discursive approach, this study researched the initial reception of these ideas and its effects on clinical practices. We gathered a corpus of discursive data from clinical cases and theoretical-doctrinal articles (from the 1960s, 1970s and 1980s). In order to examine the effects of Lacanian ideas, we analysed the difference in the way of interpreting the clinical material before and after Lacan's reception. The results of this research illuminate some epistemological problems of psychoanalysis, especially the relationship between theory and clinical practice.


2019 ◽  
Author(s):  
Liwei Cao ◽  
Danilo Russo ◽  
Vassilios S. Vassiliadis ◽  
Alexei Lapkin

<p>A mixed-integer nonlinear programming (MINLP) formulation for symbolic regression was proposed to identify physical models from noisy experimental data. The formulation was tested using numerical models and was found to be more efficient than the previous literature example with respect to the number of predictor variables and training data points. The globally optimal search was extended to identify physical models and to cope with noise in the experimental data predictor variable. The methodology was coupled with the collection of experimental data in an automated fashion, and was proven to be successful in identifying the correct physical models describing the relationship between the shear stress and shear rate for both Newtonian and non-Newtonian fluids, and simple kinetic laws of reactions. Future work will focus on addressing the limitations of the formulation presented in this work, by extending it to be able to address larger complex physical models.</p><p><br></p>


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