scholarly journals Numerical Modeling of Nondestructive Testing of Various Conductive Objects inside Metal Enclosures Using ELF/VLF Magnetic Fields

2021 ◽  
Vol 11 (8) ◽  
pp. 3665
Author(s):  
Hoyoung Kim ◽  
Vijay Harid

Nondestructive evaluation of various conductive objects through metal enclosures is investigated by using ELF/VLF magnetic induction fields in detailed simulations. ELF/VLF magnetic fields (<30 kHz) have a unique ability to penetrate highly conductive or permeable shields. Using a magnetic dipole source antenna, objects hidden inside a metal enclosure are imaged via examining distortions to the field outside the enclosure. The field distortion is parametrically studied by varying the size, conductivity, and permeability of the hidden objects. Furthermore, the importance of the conductivity of the enclosure itself is investigated using both low (106 S/m) and high (108 S/m) conductivity metallic shields. It is shown that the responses are quite sensitive to the object and shield parameters; both qualitative and quantitative properties of the field distortions are described in detail. The simulation results suggest that properties of hidden conductive or permeable objects, over a relatively wide range of parameters (both geometry and material), can be inferred nondestructively using ELF/VLF magnetic induction fields.

Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1941
Author(s):  
Igor V. Popov ◽  
Ammar Algburi ◽  
Evgeniya V. Prazdnova ◽  
Maria S. Mazanko ◽  
Vladimir Elisashvili ◽  
...  

One of the main problems in the poultry industry is the search for a viable replacement for antibiotic growth promoters. This issue requires a “one health” approach because the uncontrolled use of antibiotics in poultry can lead to the development of antimicrobial resistance, which is a concern not only in animals, but for humans as well. One of the promising ways to overcome this challenge is found in probiotics due to their wide range of features and mechanisms of action for health promotion. Moreover, spore-forming probiotics are suitable for use in the poultry industry because of their unique ability, encapsulation, granting them protection from the harshest conditions and resulting in improved availability for hosts’ organisms. This review summarizes the information on gastrointestinal tract microbiota of poultry and their interaction with commensal and probiotic spore-forming bacteria. One of the most important topics of this review is the absence of uniformity in spore-forming probiotic trials in poultry. In our opinion, this problem can be solved by the creation of standards and checklists for these kinds of trials such as those used for pre-clinical and clinical trials in human medicine. Last but not least, this review covers problems and challenges related to spore-forming probiotic manufacturing.


2021 ◽  
Vol 11 (8) ◽  
pp. 3623
Author(s):  
Omar Said ◽  
Amr Tolba

Employment of the Internet of Things (IoT) technology in the healthcare field can contribute to recruiting heterogeneous medical devices and creating smart cooperation between them. This cooperation leads to an increase in the efficiency of the entire medical system, thus accelerating the diagnosis and curing of patients, in general, and rescuing critical cases in particular. In this paper, a large-scale IoT-enabled healthcare architecture is proposed. To achieve a wide range of communication between healthcare devices, not only are Internet coverage tools utilized but also satellites and high-altitude platforms (HAPs). In addition, the clustering idea is applied in the proposed architecture to facilitate its management. Moreover, healthcare data are prioritized into several levels of importance. Finally, NS3 is used to measure the performance of the proposed IoT-enabled healthcare architecture. The performance metrics are delay, energy consumption, packet loss, coverage tool usage, throughput, percentage of served users, and percentage of each exchanged data type. The simulation results demonstrate that the proposed IoT-enabled healthcare architecture outperforms the traditional healthcare architecture.


Data ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 4
Author(s):  
Evgeny Mikhailov ◽  
Daniela Boneva ◽  
Maria Pashentseva

A wide range of astrophysical objects, such as the Sun, galaxies, stars, planets, accretion discs etc., have large-scale magnetic fields. Their generation is often based on the dynamo mechanism, which is connected with joint action of the alpha-effect and differential rotation. They compete with the turbulent diffusion. If the dynamo is intensive enough, the magnetic field grows, else it decays. The magnetic field evolution is described by Steenbeck—Krause—Raedler equations, which are quite difficult to be solved. So, for different objects, specific two-dimensional models are used. As for thin discs (this shape corresponds to galaxies and accretion discs), usually, no-z approximation is used. Some of the partial derivatives are changed by the algebraic expressions, and the solenoidality condition is taken into account as well. The field generation is restricted by the equipartition value and saturates if the field becomes comparable with it. From the point of view of mathematical physics, they can be characterized as stable points of the equations. The field can come to these values monotonously or have oscillations. It depends on the type of the stability of these points, whether it is a node or focus. Here, we study the stability of such points and give examples for astrophysical applications.


2011 ◽  
Vol 2011 ◽  
pp. 1-24 ◽  
Author(s):  
Bin Zheng ◽  
Qinghua Feng

Some new Volterra-Fredholm-type discrete inequalities in two independent variables are established, which provide a handy tool in the study of qualitative and quantitative properties of solutions of certain difference equations. The established results extend some known results in the literature.


Author(s):  
Arzu Özbey ◽  
Mehrdad Karimzadehkhouei ◽  
Evrim Kurtoğlu ◽  
Ali Koşar

Magnetic actuation of ferrofluids with dynamic magnetic fields is one of the most promising research areas with its wide and different potential application areas such as biomedical and micropumping applications. Ferrofluid has the potential of opening up new possibilities. To have more understanding about various fields of engineering, more research should be conducted by considering both the experimental and modeling aspects. The most important parameters determining the flow property, flow rates and overall system efficiency are the quality and the topology of magnetic fields used in these systems. Therefore, the methods of dynamic magnetic field generation constitute a central problem to obtain desired performance. This study includes modeling and simulation of ferrofluid actuation with dynamic magnetic fields by using the COMSOL software and reports that ferrofluid actuation can be successfully used and the simulation results agree well with the experimental results.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Veepan Kumar ◽  
Ravi Shankar ◽  
Prem Vrat

PurposeIn today’s uncertain business environment, Industry 4.0 is regarded as a viable strategic plan for addressing a wide range of manufacturing-related challenges. However, it appears that its level of adoption varies across many countries. In the case of a developing economy like India, practitioners are still in the early stages of implementation. The implementation of Industry 4.0 appears to be complex, and it must be investigated holistically in order to gain a better understanding of it. Therefore, an attempt has been made to examine the Industry 4.0 implementation for the Indian manufacturing organization in a detailed way by analyzing the complexities of relevant variables.Design/methodology/approachSAP-LAP (situation-actor-process and learning-action-performance) and an efficient interpretive ranking process (e-IRP) were used to analyze the various variables influencing Industry 4.0 implementation. The variables were identified, as per SAP-LAP, through a thorough review of the literature and based on the perspectives of various experts. The e-IRP has been used to prioritize the selected elements (i.e. actors with respect to processes and actions with respect to performance) of SAP-LAP.FindingsThis study ranked five stakeholders according to their priority in Industry 4.0 implementation: government policymakers, industry associations, research and academic institutions, manufacturers and customers. In addition, the study also prioritized important actions that need to be taken by these stakeholders.Practical implicationsThe results of this study would be useful in identifying and managing the various actors and actions related to Industry 4.0 implementation. Accordingly, their prioritized sequence would be useful to the practitioners in preparing the well-defined and comprehensive strategic roadmap for Industry 4.0.Originality/valueThis study has adopted qualitative and quantitative approaches for identifying and prioritizing different variables of Industry 4.0 implementation. This, in turn, helps the stakeholder to comprehend the concept of Industry 4.0 in a much simpler way.


2021 ◽  
pp. 92-95
Author(s):  
Александр Николаевич Остриков ◽  
Наталья Леонидовна Клейменова ◽  
Инэсса Николаевна Болгова ◽  
Максим Васильевич Копылов ◽  
Екатерина Юрьевна Желтоухова

Использование растительных масел в рационе человека необходимо для удовлетворения энергетической потребности организма и регулирования биологических процессов. В настоящей работе представлен качественный и количественный состав витаминов и токоферолов различных видов растительных масел, полученных холодным отжимом из выращенных в нашей стране расторопши, горчицы, подсолнечника, рыжика, рапса. Проведен сравнительный анализ литературных источников о наличии витаминов и токоферолов в различных растительных маслах. Количественный и качественный витаминный состав для одного и того же вида масла, по данным разных авторов, варьируется в достаточно широком диапазоне. В ходе исследования изучен витаминный состав пяти растительных масел. Результаты свидетельствуют, что наибольшей витаминной активностью обладают масла рыжиковое, расторопши и горчичное. Установлено наличие витамина А в маслах: рыжиковом (27,15±0,002 мкг%), расторопши (19,07±0,02 мкг%), горчичном (24,77±0,02 мкг%). Витамины В и В присутствуют в маслах горчичном, рыжиковом и расторопши; витамин В определен в горчичном и рыжиковом, В - в рыжиковом и расторопши. В маслах горчичном и расторопши присутствует витамин В. Наиболее богаты витамином Е масла рыжиковое (52,8±0,02 мг%), подсолнечное (48,3±0,02 мг%), расторопши (47,12±0,02 мг%). Витамин К и токоферолы определены во всех растительных маслах. Присутствие b-каротина обнаружено в рыжиковом (1,237±0,004 мг%), расторопши (0,812±0,002 мг%), подсолнечном (0,22±0,02 мг%) и горчичном (0,148±0,002 мг%) маслах. Анализируемые масла холодного отжима можно рассматривать как ценный источник при проектировании новых многоцелевых продуктов или побочных продуктов для промышленного, косметического и фармацевтического использования. The use of vegetable oils in the human diet is necessary to meet the energy needs of the body and regulate biological processes. This work presents the qualitative and quantitative composition of vitamins and tocopherols of various types of vegetable oils obtained by cold pressing from silybum marianum, mustard, sunflower, camelina, rapeseed grown in our country. A comparative analysis of the literature on the presence of vitamins and tocopherols in various vegetable oils has been carried out. The quantitative and qualitative vitamin composition for the same type of oil, according to different authors, varies in a wide range. During the study, the vitamin composition of five vegetable oils was studied. The results indicate that the following oils have the highest vitamin activity: camelina, silybum marianum and mustard. The presence of vitamin A was found in oils: camelina (27.15±0.002 μg%), silybum marianum (19.07±0.02 μg%), mustard (24.77±0.02 μg%). Vitamins B and B are present in mustard, camelina and silybum marianum oils; vitamin B is found in mustard and camelina; B in camelina and silybum marianum. Mustard and silybum marianum oils contain vitamin B. The richest in vitamin E are camelina (52.8±0.02 mg%), sunflower (48.3±0.02 mg%), silybum marianum (47.12±0.02 mg%). Vitamin K and tocopherols are found in all vegetable oils. The presence of b-carotene was found in camelina (1.237±0.004 mg%), silybum marianum (0.812±0.002 mg%), sunflower (0.22±0.02 mg%) and mustard (0.148±0.002 mg%) oils. The analyzed cold-pressed oils can be considered as a valuable resource when designing new multipurpose products or by-products for industrial, cosmetic and pharmaceutical applications.


Author(s):  
Dilip Prasad

Windmilling requirements for aircraft engines often define propulsion and airframe design parameters. The present study is focused is on two key quantities of interest during windmill operation: fan rotational speed and stage losses. A model for the rotor exit flow is developed, that serves to bring out a similarity parameter for the fan rotational speed. Furthermore, the model shows that the spanwise flow profiles are independent of the throughflow, being determined solely by the configuration geometry. Interrogation of previous numerical simulations verifies the self-similar nature of the flow. The analysis also demonstrates that the vane inlet dynamic pressure is the appropriate scale for the stagnation pressure loss across the rotor and splitter. Examination of the simulation results for the stator reveals that the flow blockage resulting from the severely negative incidence that occurs at windmill remains constant across a wide range of mass flow rates. For a given throughflow rate, the velocity scale is then shown to be that associated with the unblocked vane exit area, leading naturally to the definition of a dynamic pressure scale for the stator stagnation pressure loss. The proposed scaling procedures for the component losses are applied to the flow configuration of Prasad and Lord (2010). Comparison of simulation results for the rotor-splitter and stator losses determined using these procedures indicates very good agreement. Analogous to the loss scaling, a procedure based on the fan speed similarity parameter is developed to determine the windmill rotational speed and is also found to be in good agreement with engine data. Thus, despite their simplicity, the methods developed here possess sufficient fidelity to be employed in design prediction models for aircraft propulsion systems.


2018 ◽  
Vol 610 ◽  
pp. A84 ◽  
Author(s):  
Iker S. Requerey ◽  
Basilio Ruiz Cobo ◽  
Milan Gošić ◽  
Luis R. Bellot Rubio

Context. Photospheric vortex flows are thought to play a key role in the evolution of magnetic fields. Recent studies show that these swirling motions are ubiquitous in the solar surface convection and occur in a wide range of temporal and spatial scales. Their interplay with magnetic fields is poorly characterized, however. Aims. We study the relation between a persistent photospheric vortex flow and the evolution of a network magnetic element at a supergranular vertex. Methods. We used long-duration sequences of continuum intensity images acquired with Hinode and the local correlation-tracking method to derive the horizontal photospheric flows. Supergranular cells are detected as large-scale divergence structures in the flow maps. At their vertices, and cospatial with network magnetic elements, the velocity flows converge on a central point. Results. One of these converging flows is observed as a vortex during the whole 24 h time series. It consists of three consecutive vortices that appear nearly at the same location. At their core, a network magnetic element is also detected. Its evolution is strongly correlated to that of the vortices. The magnetic feature is concentrated and evacuated when it is caught by the vortices and is weakened and fragmented after the whirls disappear. Conclusions. This evolutionary behavior supports the picture presented previously, where a small flux tube becomes stable when it is surrounded by a vortex flow.


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