Round Aperture Research Articles

Influence of Seed Size Grading on Physiological Parameters in Pigeon Pea cv. GRG152

The experiment was initiated during December 2020–21 and 2021–22 at seed unit, UAS, Raichur, Karnataka, India to study the influence of seed size grading on physiological parameters. For grading different round aperture sieves were used, viz., 3.50 mm, 3.75 mm, 4.00 mm, 4.25 mm, and 4.50 mm. The results revealed that the 3.75 mm sieve recorded higher seed recovery (88.60%) than other sieves with better seed quality parameters like germination (85.44%), physical purity (98.00%), 100 seed weight (10.13 g), seedling vigour index(2662), and pure live seed (83.55%). During the seed processing of Pigeon pea variety GRG 152, it is advisable to utilize 3.75 mm (R) sieves for size grading in order to enhance seed recovery while adhering to the Minimum Seed Certification Standard (MSCS) required for seed approval by the Government of India. The specified screen size can be submitted to the state seed certification agency or authority for consideration in the recommended screens for the grading of pigeon pea variety GRG152 within the seed certification program.

EFFECTIVENESS OF SOCIAL MEDIA ON THE RECRUITMENT & SELECTION

INTRODUCTION The HR department’s primary responsibility is recruitment. While HR works in a variety of areas such as worker commitment, representative turn of events, legal consistency, information the board, and many others, one of the most important areas of focus for HR is to attract, select, and locally accessible qualified candidates for the organization. Recruitment is the process of attracting eligible candidates for a certain position, whereas selection is the most typical technique of identifying and selecting the best candidate for that job. Every representative’s pledges play an important role in the food and development of a firm. As a result, it is vital to select the best person to do all tasks. A bad hire may have an impact on overall business success in the same way as a square stake can not fit in a round aperture. The impact on your organization when you choose an unsuitable candidate is usually far greater than not hiring anyone at all! Enlistment is a significant essential activity for the business, not merely a functional action. As a result, there is a need to create a strong enrollment and choice interaction. The appropriate cycle considers your organization’s fantastic ability and represents your organization’s progress in attracting and hiring the suitable talent. A feasible engagement aids in the proactive formation of an ability pool, hence assisting in the achievement of medium- and long-term corporate objectives.

Local Heat Transfer Distribution On Thin Metal Foil Impinged by Array of Free Surface Jets

Abstract The present study focuses on the measurement of the local heat transfer distribution of a smooth flat plate impinged by an array of free surface jets on a thin metal foil. Local Nusselt number distributions are measured for a fixed jet diameter (d = 3 mm). The jet arrays consist of perfectly round apertures arranged in a square pattern, with a uniform spacing of 4d between adjacent jets in both the streamwise and spanwise direction. A wide range of Reynolds numbers varying from 1000 to 12500 are covered in this study. The nozzle to plate spacing (z/d) is varied between 1 to 10. The effect of the Reynolds number and nozzle to plate spacing on the local and spanwise average Nusselt number distributions are studied. The local Nusselt number exhibits an increase with nozzle-to-plate spacing within the low Reynolds number range (Re = 1000 to 2500). However, for Reynolds numbers exceeding 2500, the influence of nozzle-to-plate spacing on Nusselt number distributions remains negligible up to a nozzle-to-plate distance (z/d) of 5. Beyond this point, there is a gradual decrease in the Nusselt number value. The Nusselt number value gradually decreases beyond z/d of 5. At a Reynolds number of 1500, the Nusselt number increases by 71% for z/d = 10 in comparison to z/d = 1. Empirical correlations for local and spanwise average Nusselt number are proposed which satisfactory predict the local as well as spanwise average Nusselt number distributions.

Deep-sea ctenostome bryozoans: revision of the family Pachyzoidae, with description of a new genus and three new species from Zealandia

Pachyzoidae is a little-known family of deep-sea ctenostome Bryozoa that until now was monospecific for Pachyzoon atlanticum. Originally described from the Atlantic Ocean, the genus was also found off southeastern New Caledonia in deep waters of the geological continent of Zealandia. Pachyzoon atlanticum forms globular to flat round colonies, living on soft, muddy to sandy bottoms with a few rhizoidal cystid appendages extending from the basal, substrate-oriented side. In this study, we investigate additional pachyzoids, collected between 1965 and 2015 from over 40 sites around New Zealand, by means of detailed morphological and histological investigations. In total, several hundred colonies were encountered in the NIWA Invertebrate Collection, comprising two new species of the genus Pachyzoon, P. grischenkoi sp. nov. and P. pulvinaris sp. nov., and the new genus and species Jeanloupia zealandica gen. et sp. nov.. The genus Jeanloupia is characterized by small disc-shaped colonies with highly elongated peristomes and a quadrangular aperture, distinct from the round apertures of the genus Pachyzoon. Pachyzoid species differ in colony structure and shape, apertural papillae and polypide features such as tentacle number or digestive-tract details. Cystid appendages are non-kenozooidal, but may originate from laterally flanking kenozooids. Based on published images, alleged P. atlanticum from New Caledonia is re-interpreted as P. pulvinaris n. sp.. Morphological characters support alcyonidioidean relationships, as previously suggested. First observations on pachyzoid reproduction show macrolecithal oocytes and brooding of embryos, which seems to be the general pattern for this family. The occurrence of three new Zealandian species in a comparatively small geographical area far from the Atlantic indicates a high possibility of more species to discovered.

Manipulating the Generation of Photonic Moiré Lattices Using Plasmonic Metasurfaces.

The generation of moiré lattices by superimposing two identical sublattices at a specific twist angle has garnered significant attention owing to its potential applications, ranging from two-dimensional materials to manipulating light propagation. While macroscale moiré lattices have been widely studied, further developments in manipulating moiré lattices at the subwavelength scale would be crucial for miniaturizing and integrating platforms. Here, we propose a plasmonic metasurface design consisting of rotated nanoslits arranged within N + N' round apertures for generating focused moiré lattices. By introducing a spin-dependent geometric phase through the rotated nanoslits, an overall lens and spiral phase can be achieved, allowing each individual set of round apertures to generate a periodic lattice in the focal plane. Superimposing two sets of N and N' apertures at specific twist angles and varying phase differences allows for the superposition of two sublattices with different periods, leading to the formation of diverse moiré patterns. Our simulations and theoretical results demonstrate the feasibility of our proposed metasurface design. Due to their compactness and tunability, the utilization of metasurfaces in creating nanoscale photonic moiré lattices is anticipated to find extensive applications in integrated and on-chip optical systems.

Slit extraction and emittance results of a permanent magnet minimum-B quadrupole electron cyclotron resonance ion source

We present an experimental and simulation study of high charge state ion beams produced with a permanent magnet electron cyclotron resonance ion source (ECRIS) with minimum-B quadrupole magnetic field topology and slit extraction system. The unconventional topology generates fan-shaped plasma flux, favouring a rectangular aperture for beam extraction. We demonstrate successful low-energy transport of the slit beam, achieving up to 25 times higher beam currents compared to a round extraction aperture. Maximum beam intensities are 1.5 and 15 μA for argon 11＋ and 9＋, respectively. The results indicate microwave power-limited beam production. Emittance values are comparable to traditional ECRIS. Unlike in conventional ECRIS, the emittance increases monotonically with increasing charge state due to slit extraction, magnetic topology, and beam transport characteristics. The experimental transport efficiency for helium ranges from 32% to 50%, depending on the total beam current. The losses primarily occur due to the dipole magnet’s insufficient vertical aperture.

Study of gas and particle flow through a mask with round aperture during cold spraying

Study of gas and particle flow through a mask with round aperture during cold spraying

Psammophaga secriensia sp. nov., a New Monothalamid Foraminifera (Protista, Rhizaria) from the Romanian Black Sea Shelf

Based on molecular and morphological characters, we describe a new species of monothalamous foraminifera, Psammophaga secriensia sp. nov., that was sampled from two coastal locations (48 m and 53 m depth) on the Romanian Black Sea continental shelf. Molecular data further confirm its presence in the northeastern part of the Black Sea (Balaklava Bay, 5–10 m depth). Specimens of Psammophaga secriensia sp. nov. are characterized by an elongate to broadly pyriform test and a simple rounded aperture. The wall is translucent and the cytoplasm contains mineral grains of different sizes. The genus Psammophaga, including Psammophaga simplora and several undetermined morphotypes, has been reported from different areas of the Black Sea. Previous research using an integrative taxonomic approach has identified two additional species (Psammophaga zirconia; Psammophaga sp., Gooday et al., 2011) occurring in the Black Sea. Monothalamids are an important part of the meiobenthos in the Black Sea and our results increase the knowledge of foraminiferal diversity in this marginal sea.

Morphological, molecular, and histopathological studies on Hadjelia truncata from Columba livia domestica and its role as an environmental biological indicator.

Pigeons are a cosmopolitan group of birds with abundant and large populations associated with human activities. This study focused on determining parasitic infections within domestic pigeons (Columba livia domestica). Forty-eight pigeons were examined for infections, of which 29.16% were infected with a nematode parasite, identified as Hadjelia truncata (Habronematidae), under the koilin layer of their gizzards. The population of nematodes in infected gizzards did not exceed 20 adult worms. DNA from the gizzard worms was extracted and subjected to PCR using primers that amplify the partial 18S rDNA and cytochrome C oxidase subunit I (COX I) regions. Identification of this parasite based on microscopic study revealed the presence of trilobed lips with cephalic papillae and amphidial pores, as well as other characteristic features. In males, spicules were unequal with the presence of six pedunculated pairs of caudal papillae (4 pre- and 2 post-anal) and a tail surrounded with caudal ala. In females, the vulva was a rounded aperture located in front of the posterior end of the esophagus and uteri, which was filled with numerous embryonated eggs. DNA Sequences from partial 18S rDNA were homologous to sequences obtained from H. truncata in GenBank with a high percentage of identity. DNA sequences from mitochondrial gene COX I, however, were unique, and they were the first sequenced for H. truncata, since no sequences for this taxon were previously available in GenBank. Histopathological examination revealed enlargement of infected gizzards in comparison to non-infected ones, with the presence of necrosis and interstitial infiltration in the koilin layer. Concentrations of heavy metals (Fe, Cu, Zn, Cd, Cr, and Co) were measured using inductivity-coupled plasma in tissues (liver, muscles, and gizzards) from infected and non-infected pigeons as well as their parasites. Results showed different affinities of metals to tissues. Recovered parasites can minimize element concentration from their pigeon tissues. In Saudi Arabia, this study was considered the first report identifying pigeon nematodes and evaluating of the effects of their pathogenicity on the animals' welfare, as well as their application as a useful tool for monitoring environmental pollution.

Computational and experimental study of an ion injector of a weakly divergent ion beam for implementing a method for removing space debris objects by an ion beam

Attention to the method of removing large space debris objects by impacting them with an ion beam has not waned over the past 10 years. The application of this method to the space debris removal from the protected area of the Geostationary Earth Orbit (GEO) seems to be the most effective. This is due to a low energy consumption for removing an object to a safe orbit with ΔV≃11 m/s, which allows the removal of several objects by a single spacecraft. A service spacecraft can be developed for this purpose based on the TelSat geostationary communication satellite technology. At the same time, one of the problematic issues remains that is the development of an injector of a weakly divergent ion beam. The ion beam divergence during injection into the vacuum occurs under the insuperable influence of the ambipolar electric field acting in the beam volume. At the same time, the beam behavior depends on the initial divergence angle stipulated by the conditions of beam formation by the electrostatic acceleration system. This paper considers the results of calculated and experimental studies for the peculiarities of the formation of an ion beam in an ion extraction system with slit and round apertures. The dependence of the initial divergence half-angle on the beam perveance for both geometries was defined. In the operation of the injector designed for the space debris removal, it is necessary to ensure stability of the geometry of the ion-extraction system, which is subject to uneven thermal loading. The resulting thermomechanical deformations of the grids in the technology of ion thrusters are parried by giving the grids a plate shape. Therefore, flat grids made of a carbon-carbon composite material of a new type were used in experiments, which avoided noticeable deformations. The results of experimental investigation of the prototype of ion injector with two configurations of carbon grids (with round and slit perforation) and with the initial divergence half-angle of 2°-4° are given in this paper. The thrust control of an ion beam by changing of the screen grid potential under the condition of a constant beam perveance is considered. It is shown that such regulation is associated with a change in the Mach number, which affects the beam divergence. As an example, the calculation of the dependence of the coefficient k on the distance to the removing object is given, which is considered to be a spent satellite SUPERBIRD-A.

Design a continuous microfluidic flow cell for turbidimetric-flow injection technology: A new approach for routine analysis of active pharmaceutical formulations

In this study, a new flow injection analysis (FIA) based on a microfluidic flow cell (MFC) with a sample capacity of 40 µL is described. A Tungsten lamp directs light from a typical 2100P Portable Turbidimeter apparatus into a quartz flow cell through a round sidewall aperture of 2.0 mm and emerges through the identical aperture on the opposite side of the flow cell, where a photodiode array (light detector) detects the passing light. When compared to a traditional cuvette (25 mm x 60 mm round) with the same nominal route length, this technique improves sensitivity by around 4.0. This improvement is due to the use of a short, narrow internal diameter microfluid as the flow cell, which reduces physical dispersion. The designed flow cell has been evaluated by developing a turbidimetric method for the detection of promethazine in pure form or pharmaceutical dosages. The developed method is based on forming of a yellowish ion-pair association complex due to the reaction of promethazine and sodium tetraphenylborate (STPB) in an acidic medium. At the flow optimum conditions, the calibration curve (CC) and the LOD for promethazine were obtained 0.5-90 µg mL-1 and 0.35 µg mL-1, respectively (R2 = 0.9955).

Ion Source—Mathematical Simulation Results versus Experimental Data

To develop elements of a system for contact-free transportation of objects in space has now become an urgent task for the contemporary space-related activities. The purpose of work that is presented hereinafter was to conduct ground tests of the ion source, which is a key element of the above-mentioned system, and to compare the obtained experimental data with the mathematical simulation results in order to build a refined physical and mathematical model of the ion source. Such model was built on the basis of the classical problem regarding the motion of charged particles in an electrostatic field. Parameters of the ion source have been determined experimentally for several operating modes using various structural designs of the ion source electrodes. Two types of ion optics were tested—with slit and round apertures. Good correlation between simulation results and experimental data has been demonstrated. The optimum ion source operation modes have been identified to ensure minimum divergence angles for the plasma beam exiting from the ion source, which in its turn maximizes the pulse transmitted to the transported object.

Analysis of the Physical Properties of Seeds of Selected Viburnum Species for the Needs of Seed Sorting Operations

Viburnum is a genus of colorful and ornamental plants popular in landscape design on account of their high esthetic appeal. The physical properties of viburnum seeds have not been investigated in the literature to date. Therefore, the aim of this study was to characterize the seeds of selected Viburnum species and to search for potential relationships between their physical attributes for the needs of seed sorting operations. The basic physical parameters of the seeds of six Viburnum species were measured, and the relationships between these attributes were determined in correlation and regression analyses. The average values of the evaluated parameters were determined in the following range: terminal velocity—from 5.6 to 7.9 m s−1, thickness—from 1.39 to 1.87 mm, width—from 3.59 to 6.33 mm, length—from 5.58 to 7.44 mm, angle of external friction—from 36.7 to 43.8°, mass—from 16.7 to 35.0 mg. The seeds of V. dasyanthum, V. lentago and V. sargentii should be sorted in air separators, and the seeds of V. lantana and V. opulus should be processed with the use of mesh screens with round apertures to obtain uniform size fractions. The seeds of V. rhytodophyllum cannot be effectively sorted into batches with uniform seed mass, but they can be separated into groups with similar dimensions.

Costapex baldwinae, a new species of bathyal costellariid (Mollusca: Gastropoda: Neogastropoda: Costellariidae) from the Caribbean Sea

Costapex baldwinae, new species, is described from deep reef habitats of the southern and eastern Caribbean Sea, including Curaçao, Dominica and Guadeloupe, where it occurs at bathyal depths on sunken wood. It is assigned to the genus Costapex based on phylogenetic analyses using partial sequences of COI, 12S and 16S mitochondrial genes that reveal it to be the sister species of two Indo-Pacific members of this genus. This new species most closely resembles Costapex martinorum (Cernohorsky, 1986) from the Philippines, but differs in being smaller, and in having a slightly lower spire and more prominently beaded spiral sculpture. Of the Caribbean species of costellariids, it is somewhat similar to Nodicostellaria laterculata (Sowerby II, 1874), which occurs in shallower water and has a white or tan rather than dark brown shell, and also a taller spire, more prominent axial sculpture, and a more rounded aperture. It differs from Vexillum styria (Dall, 1889), with which it co-occurs, in having a broader shell with a lower spire, prosocline rather than opisthocline axial ribs, and more prominent, strongly beaded spiral cords. Costapex baldwinae differs from both these taxa in having rachidian teeth with three cusps rather than five cusps (N. laterculata) or seven cusps (V. styria). The genus Costapex was previously known only from Indo-Pacific species. The discovery of this new species represents a significant expansion of the range of this genus into the Caribbean Sea.

Flat electron mirror

Electron beams can be reflected by an electrode that is at a more negative potential than the cathode from which the beam is emitted. We want to design a mirror with a flat mirror electrode where the electrons are reflected at a plane very close to the electrode. The wave front of an electron can then be shaped when the mirror contains a surface topography or modulated potential. However, electron beams reflected by flat electron mirrors are usually characterized by high coefficients of chromatic and spherical aberration. When the mirror is combined with an electrostatic lens to form a tetrode mirror system, the situation deteriorates even further. This places a restrictive limit on the maximum aperture angle of the beam, and consequently also limits the attainable resolution at the image plane. We have numerically studied the dependence of these aberrations as a function of design parameters of the tetrode mirror consisting of a ground, lens, cap, and mirror electrode, and limited ourselves to only using flat electrodes with round apertures, at fixed electrode spacing. It turns out that the third order spherical aberration can be made negative. The negative third order aberration is then used to partially compensate the positive fifth order aberration. This way, a system configuration is obtained that, at 2 keV beam energy, provides a diffraction limited resolution of 7.6 nm at an image plane 25 mm from the mirror at beam semi-angles of 2.3 mrad, enabling an illumination radius of 40 μm at the mirror. The presented tetrode mirror design could spark innovative use of patterned electron mirrors as phase plates for electron microscopy in general, and for use as coherent beam splitters in Quantum Electron Microscopy in particular. An appendix presents a method to calculate the spot size of a focused beam in the presence of both third and fifth order spherical aberration coefficients, which is also applicable to Scanning (Transmission) Electron Microscopes with aberration correctors.

Cerion uva gouldi, a new fossil subspecies from Aruba (Gastropoda, Pulmonata, Cerionidae)

Cerion uva gouldi is described as a new subspecies to include only fossil and subfossil Cerion uva from Aruba. The name Cerion uva arubanumBaker, 1924 had previously been applied to all Cerion uva from Aruba, living and fossil. A recent molecular study has shown that Cerion uva arubanum, a taxon based on living type material from Aruba, is a synonym of Cerion uva uva (Linnaeus, 1758), with which it shares a preponderance of mitochondrial haplotypes. Cerion uva was widespread on Aruba during the Pleistocene, but became extinct on that island and was subsequently reintroduced from a population near Willemstad in eastern Curacao by humans within the past 800 years. Earlier authors had recognized that fossil Cerion from Aruba differ in morphology from those living on the island today, with fossils being more similar to specimens from western Curacao and Bonaire, while those living on Aruba today are most similar to Cerion uva uva from eastern Curacao. Cerion uva gouldi may be distinguished from living populations of Cerion on Aruba on the basis of its cylindrical rather than ovate shell shape, its more closely spaced whorls, and its round aperture with a uniform rather than anteriorly expanded parietal rim.

Optimization of the size and shape of the scanning aperture in autocollimator-based deflectometric profilometers.

Deflectometric profilometers based on industrial electronic autocollimators (ACs), as the ELCOMAT-3000, have become indispensable tools for precision form measurements of optical surfaces. A growing number of labs at synchrotron and free electron laser x-ray facilities are going for BESSY-II NOM-like versions of the AC-based profilometers. These tools have proven capable of characterizing state-of-the-art aspherical x-ray optics with an accuracy on the level of 100 nrad (root-mean-square) over the spatial frequency range limited by the size of the aperture used in the profilometer. Typically, a round aperture with a diameter of about 2.5 mm is used. Previous investigations have shown that with the optimally aligned 2.5-mm aperture, the spatial resolution of a NOM-like profilometer corresponding to the first zero-crossing of the optical transform function (OTF) is ∼1.2 mm. In this paper, we investigate the performance of an AC ELCOMAT-3000 for a slope profilometer with different aperture sizes and shapes. The results of angular calibration of the AC equipped with circular and rectangular apertures placed at different distances from the AC are discussed. The calibration was performed at the Physikalisch-Technische Bundesanstalt using the original experimental arrangements, also discussed in the paper. The OTF measurements with the specially developed test sample with chirped surface slope profiles were performed at the Advanced Light Source X-Ray Optics Laboratory (XROL) in application to a new optical surface measuring system under development at the XROL. In the OTF measurements, we have shown that application of a rectangular aperture with dimensions of 1.5 mm × 3 mm improves the spatial resolution in the tangential direction by a factor of ∼1.4 compared to that of the standard circular aperture of 2.5-mm diameter. We believe that the results of our investigations are crucial for reaching fundamental metrological limits in deflectometric profilometry utilizing state-of-the-art electronic autocollimators.

Angular Diversity Aperture (ADA) Receivers for Indoor Multiple-Input Multiple-Output (MIMO) Visible Light Communications (VLC)

The angular diversity aperture (ADA) receiver is a new form of optical wireless receiver which is made up of a number of receiving elements (REs) each consisting of a photodiode (PD) located below an aperture in an opaque screen. Previous work on the use of ADA receivers for visible light communication (VLC) analyzes only REs with round apertures and photodiodes with a limited range of parameters. This paper extends the analysis to calculate the channel gains for REs with for both round and square apertures and PDs and for more parameters. Graphs show how the gain varies as a function of the relative orientation of the transmitter and receiver for ten different designs. It is shown that the directionality of an RE depends on the offset of the PD from the aperture and that the field of view depends on the distance between the aperture and the PD. Detailed theoretical analysis and extensive simulation results demonstrate the bit error rate (BER) performance of receivers based on these ten designs in a multiple-input multiple-output (MIMO) VLC application. The round and square designs are found to have very similar BERs. It is shown that, even with high levels of shot noise, good BER results can be achieved throughout a typical scenario.

First record of marine gastropods (wentletraps) from mid-Cretaceous Burmese amber

Abstracts Gastropod fossils are rarely preserved in amber with only a few records of terrestrial snails. Two new species, Epitonium (Epitonium) zhuoi n. sp. and Epitonium (Papyriscala) lyui n. sp. are described based on two well-preserved specimens from mid-Cretaceous amber from northern Myanmar. Highresolution three-dimensional images using X-ray micro-computed tomography (micro-CT) are provided. These species can be attributed to the family Epitoniidae (wentletraps) based on the shell characters such as the slender and conical shell-shape, numerous whorls, round aperture and regular, axial sculpture of high, sharply-ribbed costae. Our find is the first record of marine gastropods preserved in amber, and suggests that the Burmese amber forest probably existed close to the seashore.

Shell morphology and color of the subtidal whelk Buccinum undatum exhibit fine-scaled spatial patterns.

Geographical patterns in morphology can be the result of divergence among populations due to neutral or selective changes and/or phenotypic plasticity in response to different environments. Marine gastropods are ideal subjects on which to explore these patterns, by virtue of the remarkable intraspecific variation in life‐history traits and morphology often observed across relatively small spatial scales. The ubiquitous N‐Atlantic common whelk (Buccinum undatum) is well known for spatial variation in life‐history traits and morphology. Previous studies on genetic population structure have revealed that it exhibits significant differentiation across geographic distances. Within Breiðafjörður Bay, a large and shallow bay in W‐Iceland, genetic differentiation was demonstrated between whelks from sites separated by just 20 km. Here, we extended our previous studies on the common whelk in Breiðafjörður Bay by quantifying phenotypic variation in shell morphology and color throughout the Bay. We sought to test whether trait differentiation is dependent on geographic distance and/or environmental variability. Whelk in Breiðafjörður Bay displayed fine‐scale patterns of spatial variation in shape, thickness, and color diversity. Differentiation increased with increasing distance between populations, indicating that population connectivity is limited. Both shape and color varied along a gradient from the inner part of the bay in the east to the outer part in the west. Whelk shells in the innermost part of Breiðafjörður Bay were thick with an elongate shell, round aperture, and low color diversity, whereas in the outer part of the bay the shells were thinner, rounder, with a more elongate aperture and richer color diversity. Significant site‐specific difference in shell traits of the common whelk in correlation with environmental variables indicates the presence of local ecotypes and limited demographic connectivity.