HRTEMFringeAnalyzer a free python module for an automated analysis of fringe pattern in transmission electron micrographs

A python module (HRTEMFringeAnalyzer ) is reported to evaluate the local crystallinity of samples from high‐resolution transmission electron microscopy images in a mostly automated fashion. The user only selects the size of a square analyser window and a step size which translates the window in the micrograph. Together they define the resolution of the results obtained. Regions where fringe patterns are visible are identified and their lattice spacing d and direction ? as well as the corresponding mean errors σ determined. is proportional to the coherence length of the structure, whereas is a measure of how well the direction of the fringes is defined. Maps of these four indicators are computed. The performance of the program is demonstrated on two very different samples: ill‐crystalline carbon deposits on a coked Ni/LFNO (reduced LaFe_0.8Ni_0.2O) catalyst and well‐crystallized nanoparticles of zinc doped ceria. In the latter case, the automatic segmentation of large aggregates into individual crystalline domains is achieved by ? maps.     

A NEW METHOD FOR THE SYNTHETIC DETERMINATION OF THE LOSSES OF THREE–PHASE INDUCTION MOTORS

ABSTRACT

A new method for the synthetic determination of the losses of three–phase induction motors by means of direct tests is described. The tests are carried out with a reduced supply voltage and a reduced braking torque: subsequent calculations to refer the results to rated values are then applied.

Using this procedure, a considerable extension of the power range over which direct methods can be employed becomes possible, whilst avoiding the use of correspondingly more powerful braking devices.

A few experimental tests confirm the validity of the proposed method. Moreover, the potentialities of the method are discussed; then a few error analysis considerations are developed; finally, some possible thermal referring procedures are proposed.     

D.C. POLARIZED CURRENT TRANSFORMERS FOR THE MEASUREMENT OF HARMONIC NOISE

ABSTRACT

The paper describes an algorithm for the design of a special current transformer (C.T.), suited to measure the residual harmonic content of fluctuating direct currents, generated by static convertors on their D.C. side. The use of a suitably proportioned C.T. allows the galvanic insulation and the filtering of the D.C. component (without employing high-pass filters).

The design of the C.T. is affected by the high value of the D.C. component, which implies the use of a gapped magnetic core.

An in-depth study of a C.T. model has been carried out: particular attention is devoted to the effects of the distributed capacitances of the windings.

The paper also analyses the experimental results obtained during tests carried out on a prototype C.T., comparing them with the values calculated from the theoretical model.     

Evaluation of contrasting techniques for X‐ray imaging of velvet worms (Onychophora)

Non‐invasive imaging techniques like X‐ray computed tomography have become very popular in zoology, as they allow for simultaneous imaging of the internal and external morphology of organisms. Nevertheless, the effect of different staining approaches required for this method on samples lacking mineralized tissues, such as soft‐bodied invertebrates, remains understudied. Herein, we used synchrotron radiation‐based X‐ray micro‐computed tomography to compare the effects of commonly used contrasting approaches on onychophorans – soft‐bodied invertebrates important for studying animal evolution. Representatives of Euperipatoides rowelli were stained with osmium tetroxide (vapour or solution), ruthenium red, phosphotungstic acid, or iodine. Unstained specimens were imaged using both standard attenuation‐based and differential phase‐contrast setups to simulate analyses with museum material. Our comparative qualitative analyses of several tissue types demonstrate that osmium tetroxide provides the best overall tissue contrast in onychophorans, whereas the remaining staining agents rather favour the visualisation of specific tissues and/or structures. Quantitative analyses using signal‐to‐noise ratio measurements show that the level of image noise may vary according to the staining agent and scanning medium selected. Furthermore, box‐and‐whisker plots revealed substantial overlap in grey values among structures in all datasets, suggesting that a combination of semiautomatic and manual segmentation of structures is required for comprehensive 3D reconstructions of Onychophora, irrespective of the approach selected. Our results show that X‐ray micro‐computed tomography is a promising technique for studying onychophorans and, despite the benefits and disadvantages of different staining agents for specific tissues/structures, this method retrieves informative data that may eventually help address evolutionary questions long associated with Onychophora.     

KINETIC CHARACTERISTICS OF A BATCH ADSORBER OR AN ION EXCHANGE DEVICE OPERATED UNDER NONISOTHERMAL CONDITIONS

Abstract

A model was formulated for a batch adsorber or ion exchange device with heat generation inside the bulk liquid due to mixing or electrical heating and due to heat of adsorption. Internal and external particle mass and heat transfer gradients and heat transfer through the vessel wall were included. The effective diffusion coefficient was taken to be temperature dependent. Numerical calculations (by orthogonal collocation) give conditions for the existence of intra particle nonisothermity and show the effect of mixing and process temperature on adsorption kinetics.     

Application of holographic diffractive doublets as collimators for highly elliptical light beams edge emitted from diode lasers

Two schemes for collimation of diode laser light beams with high cross-sectional ellipticity by means of a doublet of holographic diffractive elements are proposed and designed; one of the schemes is realized and tested. In both the schemes the first element of the doublet collimates the beam in the plane of the longer axis of the ellipse, and the second element collimates it in the perpendicular plane. Each element simulates a cylindrical lens. The set-up with the focal line of the cylindrical beam oriented perpendicular to the meridional plane is realized experimentally. The elements are holographic surface-relief gratings recorded in photoresist. For recording, only homocentric diverging beams are used, which minimizes potential aberrations and optical dirt. The parameters of the elements are computed using four equations, including one equation for compensation of the aberration of the lowest order. The doublet is proposed for the He—Ne red wavelength. A collimated He—Ne laser beam is employed for quality testing of collimation in a reverse way, with this beam impinging upon the second element. Characteristics of an outgoing beam from the first element of the doublet are recorded with a charge-coupled device camera. Calculated spot diagrams are compared with cylindrical focal lines captured separately from both the elements.     

Indian medicinal plants are effective in the treatment and management of COVID-19

Indian medicinal plants are referred to as the “nectar of life” owing to their phytochemicals and bioactive complexes that are beneficial in treating diseases. Coronavirus disease 2019 (COVID-19) is a global health issue without any proper medication. The indigenous plants of India can be exploited to control the precise signs of SARS-CoV-2. The Ministry of AYUSH (Ayurveda, Yoga and Naturopathy, Unani, Siddha, and Homeopathy) has advised routine usage of medicinal plants for COVID-19. Medicinal plants like Zingiber officinalis, Azadirachta indica, Ocimum sanctum, Nigella sativa, Withania somnifera, Curcuma longa, Piper nigrum, Allium sativum, Tinospora cordifolia, etc. have immunity-boosting, antiviral, antibacterial, antioxidant and anti-inflammatory actions that can suppress and treat symptoms of COVID-19. In vitro, in vivo as well as in silico validation, these phytochemicals can help us to manage and treat COVID-19 disease. This integration of traditional knowledge in the prophylaxis of corona infection and current skills validating it for the development of precise and powerful therapeutic approaches will more efficiently resolve different clinical aspects of COVID-19. The review focuses on both traditional and emergent methods to prevent and treat COVID-19 with various Indian medicinal plants along with their phytochemicals.