In situ capture of impact-induced progressive damage and delamination in fiberglass composite laminate with a high-speed optical imaging method

One of the most important brain rhythms is that which generates involuntary breathing movements. The lower brain stem contains neural circuitry for respiratory rhythm generation in mammals. To date, microsectioning and selective lesioning studies have revealed anatomical regions necessary for respiratory rhythmogenesis. Although respiratory neurons distributed within these regions can be identified by their firing patterns in different phases of the respiratory cycle, conventional electrophysiology techniques have limited the study of spatial organization within this network. Optical imaging techniques offer the potential for monitoring the spatiotemporal activity of large groups of neurons simultaneously. Using high-speed voltage-sensitive dye imaging and spatial correlation analysis in an arterially perfused in situ preparation of the juvenile rat, we determined the spatial distribution of respiratory neuronal activity in a region of the ventrolateral respiratory group containing the pre-Bötzinger complex (pBC) during spontaneous eupneic breathing. While distinctly pre- and postinspiratory-related responses were spatially localizable on length scales less than 100 μm, we found the studied area on whole exhibited a spatial mixture of phase-spanning and postinspiratory-related activity. Additionally, optical recordings revealed significant widespread hyperpolarization, suggesting inhibition in the same region during expiration. This finding is consistent with the hypothesis that inhibitory neurons play a crucial role in the inspiration-expiration phase transition in the pBC. To our knowledge this is the first optical imaging of a near fully intact in situ preparation that exhibits both eupneic respiratory activity and functional reflexes.

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TECHNICAL DEVELOPMENT OF THE MAGNETO-OPTICAL IMAGING METHOD IN THE RESEARCH OF RELIEF SIGNS OF THE METAL OBJECTS

Criminalistics and Forensics ◽

10.33994/kndise.2020.66.55 ◽

2021 ◽

pp. 746-768

Author(s):

O. Koshel

Keyword(s):

Optical Imaging ◽

High Speed ◽

High Efficiency ◽

Science Studies ◽

Operating Conditions ◽

Optical Methods ◽

Imaging Method ◽

Practical Application ◽

Near Surface ◽

Non Destructive

The study of relief marking of metal objects is one of the constantly demanded areas of expert research, especially for objects such as weapons and vehicles. The question of choosing a research method for these objects, which is constantly topical for an expert, acquires particular relevance in the case of rare and historical objects, new expensive products. In the last decade, a non-destructive method of magneto-optical imaging, which was developed at the Kyiv Polytechnic Institute more than 20 years ago, has been successfully applied abroad for these studies in 40 countries. During this time, the technical implementation of the method has been developed, the technical components of the complex have been significantly improved and changed. In 2008 basing on the results of practical application on specially designed test objects, including those with three thicknesses of paint coatings, the developers carried out studies in which they assessed the sensitivity of magnetic powder, electrochemical and magneto-optical methods. Obtained results demonstrated a higher sensitivity of the magneto-optical method for thin-walled objects and the sensitivity for thick-walled objects is not worse than other methods. Practical application of the modern REGULA 7517 complex in expert studies under various operating conditions confirms its high sensitivity, testifies to the high speed of operation, reliability, autonomy of the complex and wide temperature conditions of use. The high efficiency of the non-destructive method of magneto-optical imaging makes it possible to consider it as one of the most promising methods in trace studies, as well as in materials science studies, where information on the state and structure of the surface and near-surface layers of metal objects is needed.

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An atomic-resolution microscope study of Al contracts on GaAs

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100145005 ◽

1986 ◽

Vol 44 ◽

pp. 726-727

Author(s):

Z. Liliental-Weber ◽

C. Nelson ◽

R. Ludeke ◽

R. Gronsky ◽

J. Washburn

Keyword(s):

High Speed ◽

Schottky Contacts ◽

Detailed Knowledge ◽

The Past ◽

Semiconductor Interfaces ◽

Deposited Metal ◽

Microwave Applications ◽

Free Interfaces ◽

Potential Use

The properties of metal/semiconductor interfaces have received considerable attention over the past few years, and the Al/GaAs system is of special interest because of its potential use in high-speed logic integrated optics, and microwave applications. For such materials a detailed knowledge of the geometric and electronic structure of the interface is fundamental to an understanding of the electrical properties of the contact. It is well known that the properties of Schottky contacts are established within a few atomic layers of the deposited metal. Therefore surface contamination can play a significant role. A method for fabricating contamination-free interfaces is absolutely necessary for reproducible properties, and molecularbeam epitaxy (MBE) offers such advantages for in-situ metal deposition under UHV conditions

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High-speed volumetric two-photon fluorescence imaging of neurovascular dynamics

Nature Communications ◽

10.1038/s41467-020-19851-1 ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 1

Author(s):

Jiang Lan Fan ◽

Jose A. Rivera ◽

Wei Sun ◽

John Peterson ◽

Henry Haeberle ◽

...

Keyword(s):

Blood Flow ◽

High Speed ◽

Laser Scanning ◽

Three Dimensional ◽

Laser Scanning Microscopy ◽

Fluorescence Signal ◽

Imaging Method ◽

Spatiotemporal Resolution ◽

Two Photon

AbstractUnderstanding the structure and function of vasculature in the brain requires us to monitor distributed hemodynamics at high spatial and temporal resolution in three-dimensional (3D) volumes in vivo. Currently, a volumetric vasculature imaging method with sub-capillary spatial resolution and blood flow-resolving speed is lacking. Here, using two-photon laser scanning microscopy (TPLSM) with an axially extended Bessel focus, we capture volumetric hemodynamics in the awake mouse brain at a spatiotemporal resolution sufficient for measuring capillary size and blood flow. With Bessel TPLSM, the fluorescence signal of a vessel becomes proportional to its size, which enables convenient intensity-based analysis of vessel dilation and constriction dynamics in large volumes. We observe entrainment of vasodilation and vasoconstriction with pupil diameter and measure 3D blood flow at 99 volumes/second. Demonstrating high-throughput monitoring of hemodynamics in the awake brain, we expect Bessel TPLSM to make broad impacts on neurovasculature research.

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Spatially Resolved Experimental Modal Analysis on High-Speed Composite Rotors Using a Non-Contact, Non-Rotating Sensor

Sensors ◽

10.3390/s21144705 ◽

2021 ◽

Vol 21 (14) ◽

pp. 4705

Author(s):

Julian Lich ◽

Tino Wollmann ◽

Angelos Filippatos ◽

Maik Gude ◽

Juergen Czarske ◽

...

Keyword(s):

High Speed ◽

Natural Frequencies ◽

Mode Shapes ◽

Fiber Reinforced ◽

Structural Dynamic ◽

Spatially Resolved ◽

Glass Fiber Reinforced ◽

Vibration Responses ◽

And Performance

Due to their lightweight properties, fiber-reinforced composites are well suited for large and fast rotating structures, such as fan blades in turbomachines. To investigate rotor safety and performance, in situ measurements of the structural dynamic behaviour must be performed during rotating conditions. An approach to measuring spatially resolved vibration responses of a rotating structure with a non-contact, non-rotating sensor is investigated here. The resulting spectra can be assigned to specific locations on the structure and have similar properties to the spectra measured with co-rotating sensors, such as strain gauges. The sampling frequency is increased by performing consecutive measurements with a constant excitation function and varying time delays. The method allows for a paradigm shift to unambiguous identification of natural frequencies and mode shapes with arbitrary rotor shapes and excitation functions without the need for co-rotating sensors. Deflection measurements on a glass fiber-reinforced polymer disk were performed with a diffraction grating-based sensor system at 40 measurement points with an uncertainty below 15 μrad and a commercial triangulation sensor at 200 measurement points at surface speeds up to 300 m/s. A rotation-induced increase of two natural frequencies was measured, and their mode shapes were derived at the corresponding rotational speeds. A strain gauge was used for validation.

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Enhanced Grain Refinement of W18Cr4V High‐Speed Steel using in situ TiN‐Nb‐Cr@Graphene/Fe Nanocomposite Inoculant

steel research international ◽

10.1002/srin.202100094 ◽

2021 ◽

Author(s):

Lina Bai ◽

Chunxiang Cui ◽

Jianjun Zhang ◽

Lichen Zhao ◽

Guixing Zheng ◽

...

Keyword(s):

Grain Refinement ◽

High Speed ◽

High Speed Steel

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Observing progressive damage in carbon fiber epoxy laminate composites via 3D in-situ X-ray tomography

Engineering Fracture Mechanics ◽

10.1016/j.engfracmech.2021.107626 ◽

2021 ◽

pp. 107626

Author(s):

Alejandra M. Ortiz-Morales ◽

Imad Hanhan ◽

Jose Javier Solano ◽

Michael D. Sangid

Keyword(s):

Carbon Fiber ◽

Progressive Damage ◽

Laminate Composites ◽

X Ray ◽

Carbon Fiber Epoxy

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Influence of Hydrogeochemistry on Tunnel Drainage in Evaporitic Formations: El Regajal Tunnel Case Study (Aranjuez, Spain)

Sustainability ◽

10.3390/su13031505 ◽

2021 ◽

Vol 13 (3) ◽

pp. 1505

Author(s):

Ignacio Menéndez Pidal ◽

Jose Antonio Mancebo Piqueras ◽

Eugenio Sanz Pérez ◽

Clemente Sáenz Sanz

Keyword(s):

High Speed ◽

Civil Engineering ◽

Saturation Index ◽

The Subject ◽

Under Construction ◽

Underground Flow ◽

Very High ◽

Over Time

Many of the large number of underground works constructed or under construction in recent years are in unfavorable terrains facing unusual situations and construction conditions. This is the case of the subject under study in this paper: a tunnel excavated in evaporitic rocks that experienced significant karstification problems very quickly over time. As a result of this situation, the causes that may underlie this rapid karstification are investigated and a novel methodology is presented in civil engineering where the use of saturation indices for the different mineral specimens present has been crucial. The drainage of the rock massif of El Regajal (Madrid-Toledo, Spain, in the Madrid-Valencia high-speed train line) was studied and permitted the in-situ study of the hydrogeochemical evolution of water flow in the Miocene evaporitic materials of the Tajo Basin as a full-scale testing laboratory, that are conforms as a whole, a single aquifer. The work provides a novel methodology based on the calculation of activities through the hydrogeochemical study of water samples in different piezometers, estimating the saturation index of different saline materials and the dissolution capacity of the brine, which is surprisingly very high despite the high electrical conductivity. The circulating brine appears unsaturated with respect to thenardite, mirabilite, epsomite, glauberite, and halite. The alteration of the underground flow and the consequent renewal of the water of the aquifer by the infiltration water of rain and irrigation is the cause of the hydrogeochemical imbalance and the modification of the characteristics of the massif. These modifications include very important loss of material by dissolution, altering the resistance of the terrain and the increase of the porosity. Simultaneously, different expansive and recrystallization processes that decrease the porosity of the massif were identified in the present work. The hydrogeochemical study allows the evolution of these phenomena to be followed over time, and this, in turn, may facilitate the implementation of preventive works in civil engineering.

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In situ imaging reveals disparity between prostaglandin localization and abundance of prostaglandin synthases

Communications Biology ◽

10.1038/s42003-021-02488-1 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Kyle D. Duncan ◽

Xiaofei Sun ◽

Erin S. Baker ◽

Sudhansu K. Dey ◽

Ingela Lanekoff

Keyword(s):

Mass Spectrometry Imaging ◽

Rna Localization ◽

Imaging Method ◽

Related Protein ◽

Uterine Tissue ◽

Tissue Localization ◽

Physiological Processes ◽

Conditional Deletion ◽

Regional Abundance

AbstractProstaglandins are important lipids involved in mediating many physiological processes, such as allergic responses, inflammation, and pregnancy. However, technical limitations of in-situ prostaglandin detection in tissue have led researchers to infer prostaglandin tissue distributions from localization of regulatory synthases, such as COX1 and COX2. Herein, we apply a novel mass spectrometry imaging method for direct in situ tissue localization of prostaglandins, and combine it with techniques for protein expression and RNA localization. We report that prostaglandin D2, its precursors, and downstream synthases co-localize with the highest expression of COX1, and not COX2. Further, we study tissue with a conditional deletion of transformation-related protein 53 where pregnancy success is low and confirm that PG levels are altered, although localization is conserved. Our studies reveal that the abundance of COX and prostaglandin D2 synthases in cellular regions does not mirror the regional abundance of prostaglandins. Thus, we deduce that prostaglandins tissue localization and abundance may not be inferred by COX or prostaglandin synthases in uterine tissue, and must be resolved by an in situ prostaglandin imaging.

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