scholarly journals Low Electron Temperature Plasma Diagnosis: Revisiting Langmuir Electrostatic Probes

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1158
Author(s):  
Guillermo Fernando Regodón ◽  
Juan Manuel Díaz-Cabrera ◽  
José Ignacio Fernández Palop ◽  
Jerónimo Ballesteros
Keyword(s):  
Electron Temperature ◽  
Virtual Instrument ◽  
Measurement Method ◽  
Characteristic Curve ◽  
Diagnostic Methods ◽  
Industrial Processes ◽  
Probe Design ◽  
Temperature Plasma ◽  
Plasma Diagnosis ◽  
Advantages And Disadvantages

This article describes a method of measurement of the current-to-probe voltage characteristic curve of a Langmuir electrostatic probe immersed in a plasma characterized by a low electron temperature that is only one order of magnitude higher than room temperature. These plasmas are widely used in industrial processes related to surface technology, polymers, cleaning, nanostructures, etc. The measurement method complies with the strict requirements to perform representative plasma diagnosis, particularly in the ion saturation zone when the probe is polarized much more negatively that the potential of the plasma bulk surrounding the probe and allows to diagnose the plasma very quickly and locally, making it possible to better monitor and control the plasma discharge uniformity and time drift. The requirements for the Langmuir probe design, the data acquisition and data treatment are thoroughly explained and their influence on the measurement method is also described. Subsequently, the article describes different diagnostic methods of the magnitudes that characterize the plasma, based on theoretical models of that characteristic curve. Each of these methods is applied to different zones of the measured characteristic curve, the obtained results being quite similar, which guarantees the quality of the measurements. The advantages and disadvantages of each method are discussed. A series of measurements of the plasma density for different plasma conditions shows that the method is sensitive enough that the temperature of the ions needs to be taken into account in the data processing. Finally, a Virtual Instrument is included in the LabView environment that performs the diagnosis process with sufficient speed and precision, which allows the scientist to control the parameters that characterize the plasma to increase the quality and performance of the industrial processes in which the plasma diagnosis is to be used. The Virtual Instrument can be downloaded for free from a link that is included, in order to be easily adapted to the usual devices in a plasma laboratory.

scholarly journals Selected methods of electron-and ion-diagnostics in tokamak scrape-off-layer

Nukleonika ◽  
2015 ◽  
Vol 60 (2) ◽  
pp. 199-206
Author(s):  
Marek J. Sadowski
Keyword(s):  
Nuclear Fusion ◽  
Plasma Heating ◽  
Fusion Energy ◽  
High Energy ◽  
Diagnostic Methods ◽  
Fusion Reactions ◽  
Temperature Plasma ◽  
Fast Electrons ◽  
Advantages And Disadvantages ◽  
Direct Measurements

Abstract This invited paper considers reasons why exact measurements of fast electron and ion losses in tokamaks, and particularly i n a scrape-off-layer and near a divertor region, are necessary in order to master nuclear fusion energy production. Attention is also paid to direct measurements of escaping fusion products from D-D and D-T reactions, and in particular of fast alphas which might be used for plasma heating. The second part describes the generation of so-called runaway and ripple-born electrons which might induce high energy losses and cause severe damages of internal walls in fusion facilities. Advantages and disadvantages of different diagnostic methods applied for studies of such fast electrons are discussed. Particular attention is paid to development of a direct measuring technique based on the Cherenkov effect which might be induced by fast electrons in appropriate radiators. There are presented various versions of Cherenkov-type probes which have been developed by the NCBJ team and applied in different tokamak experiments. The third part is devoted to direct measurements of fast ions (including those produced by the nuclear fusion reactions) which can escape from a high-temperature plasma region. Investigation of fast fusion-produced protons from tokamak discharges is reported. New ion probes, which were developed by the NCBJ team, are also presented. For the first time there is given a detailed description of an ion pinhole camera, which enables irradiation of several nuclear track detectors during a single tokamak discharge, and a miniature Thomson-type mass-spectrometer, which can be used for ion measurements at plasma borders.

Trends in Diagnosis for Active Tuberculosis Using Nanomaterials

2019 ◽  
Vol 26 (11) ◽  
pp. 1946-1959 ◽  
Author(s):  
Le Minh Tu Phan ◽  
Lemma Teshome Tufa ◽  
Hwa-Jung Kim ◽  
Jaebeom Lee ◽  
Tae Jung Park
Keyword(s):  
Sensitivity And Specificity ◽  
High Efficiency ◽  
Point Of Care ◽  
High Sensitivity ◽  
Signs And Symptoms ◽  
Diagnostic Methods ◽  
Advantages And Disadvantages ◽  
Treatment And Prevention ◽  
Clinical Tools ◽  
Diagnostic Applications

Background:Tuberculosis (TB), one of the leading causes of death worldwide, is difficult to diagnose based only on signs and symptoms. Methods for TB detection are continuously being researched to design novel effective clinical tools for the diagnosis of TB.Objective:This article reviews the methods to diagnose TB at the latent and active stages and to recognize prospective TB diagnostic methods based on nanomaterials.Methods:The current methods for TB diagnosis were reviewed by evaluating their advantages and disadvantages. Furthermore, the trends in TB detection using nanomaterials were discussed regarding their performance capacity for clinical diagnostic applications.Results:Current methods such as microscopy, culture, and tuberculin skin test are still being employed to diagnose TB, however, a highly sensitive point of care tool without false results is still needed. The utilization of nanomaterials to detect the specific TB biomarkers with high sensitivity and specificity can provide a possible strategy to rapidly diagnose TB. Although it is challenging for nanodiagnostic platforms to be assessed in clinical trials, active TB diagnosis using nanomaterials is highly expected to achieve clinical significance for regular application. In addition, aspects and future directions in developing the high-efficiency tools to diagnose active TB using advanced nanomaterials are expounded.Conclusion:This review suggests that nanomaterials have high potential as rapid, costeffective tools to enhance the diagnostic sensitivity and specificity for the accurate diagnosis, treatment, and prevention of TB. Hence, portable nanobiosensors can be alternative effective tests to be exploited globally after clinical trial execution.

Scattering of electromagnetic waves by hybrid waves in a two-electron-temperature plasma

1991 ◽  
Vol 46 (1) ◽  
pp. 99-106 ◽  
Author(s):  
S. K. Sharma ◽  
A. Sudarshan
Keyword(s):  
Growth Rate ◽  
Electron Temperature ◽  
High Frequency ◽  
Electromagnetic Waves ◽  
Low Frequency ◽  
Lower Hybrid ◽  
Stimulated Scattering ◽  
Coupled Modes ◽  
Temperature Plasma ◽  
Electrostatic Perturbation

In this paper, we use the hydrodynamic approach to study the stimulated scattering of high-frequency electromagnetic waves by a low-frequency electrostatic perturbation that is either an upper- or lower-hybrid wave in a two-electron-temperature plasma. Considering the four-wave interaction between a strong high-frequency pump and the low-frequency electrostatic perturbation (LHW or UHW), we obtain the dispersion relation for the scattered wave, which is then solved to obtain an explicit expression for the growth rate of the coupled modes. For a typical Q-machine plasma, results show that in both cases the growth rate increases with noh/noc. This is in contrast with the results of Guha & Asthana (1989), who predicted that, for scattering by a UHW perturbation, the growth rate should decrease with increasing noh/noc.

scholarly journals Two-temperature magnetohydrodynamic simulations for sub-relativistic active galactic nucleus jets: dependence on the fraction of the electron heating

2020 ◽  
Vol 493 (4) ◽  
pp. 5761-5772 ◽  
Author(s):  
Takumi Ohmura ◽  
Mami Machida ◽  
Kenji Nakamura ◽  
Yuki Kudoh ◽  
Ryoji Matsumoto
Keyword(s):  
Electron Temperature ◽  
X Rays ◽  
Ion Temperature ◽  
Temperature Plasma ◽  
Electron Heating ◽  
Coulomb Collisions ◽  
X Ray ◽  
Jet Plasma ◽  
Magnetohydrodynamic Simulations ◽  
Two Temperature

ABSTRACT We present the results of two-temperature magnetohydrodynamic simulations of the propagation of sub-relativistic jets of active galactic nuclei. The dependence of the electron and ion temperature distributions on the fraction of electron heating, fe, at the shock front is studied for fe = 0, 0.05, and 0.2. Numerical results indicate that in sub-relativistic, rarefied jets, the jet plasma crossing the terminal shock forms a hot, two-temperature plasma in which the ion temperature is higher than the electron temperature. The two-temperature plasma expands and forms a backflow referred to as a cocoon, in which the ion temperature remains higher than the electron temperature for longer than 100 Myr. Electrons in the cocoon are continuously heated by ions through Coulomb collisions, and the electron temperature thus remains at Te > 109 K in the cocoon. X-ray emissions from the cocoon are weak because the electron number density is low. Meanwhile, X-rays are emitted from the shocked intracluster medium (ICM) surrounding the cocoon. Mixing of the jet plasma and the shocked ICM through the Kelvin–Helmholtz instability at the interface enhances X-ray emissions around the contact discontinuity between the cocoon and shocked ICM.

scholarly journals SCREENING IN CARDIOLOGY

2018 ◽  
Vol 7 (4) ◽  
pp. 92-100 ◽  
Author(s):  
I. V. Samorodskaya
Keyword(s):  
Risk Factors ◽  
The United States ◽  
Diagnostic Methods ◽  
Screening Programs ◽  
Advantages And Disadvantages ◽  
Target Populations ◽  
Screening Strategies ◽  
National Programs ◽  
Expensive Process ◽  
Current Guidelines

The organization of screening is a complex and expensive process. Many countries have implemented and continue to implement various health screening programs in the population groups. However, there is a process of refusing to screen certain diseases. In cardiology, some screening strategies are integrated in the national programs aimed at identifying risk factors and preventing chronic non-communicable diseases. None of the countries have established the screening of the entire population for all known cardiovascular diseases (CVD) using all known diagnostic methods. The decision to screen individuals for CVDs / risk factors within the opportunistic screening in the target populations in different countries varies, since it depends on many factors. The article discusses the advantages and disadvantages of screening for CVD, presents current guidelines from professional communities and national services of the United States of America, Great Britain, and Canada.

scholarly journals Problems of diagnostics and treatment of diffuse — toxic goiter (Graves’ disease)

2019 ◽  
Vol 14 (2) ◽  
Author(s):  
Saydiganikxodja I. Ismailov ◽  
Komila Kh. Khayitboyeva
Keyword(s):  
Surgical Treatment ◽  
Iodine Deficiency ◽  
Diagnostic Methods ◽  
Graves Disease ◽  
Minimal Risk ◽  
Familial Predisposition ◽  
Advantages And Disadvantages ◽  
Radioiodine Ablation ◽  
Treatment Indications ◽  
Toxic Goiter

The article is devoted to prevalence, contemporary diagnostic methods and treatment of Grave’s disease. Advantages and disadvantages of different treatment options are discussed. The cause of the disease can be environmental conditions, infectious diseases, severe operational intervention, drugs, trauma, especially brain traumas, iodine deficiency and radiation damage of thyroid in iodine deficiency conditions, familial predisposition. The ideal treatment of Graves’ disease should ensure a fairly rapid elimination of clinical symptoms of thyrotoxicosis, return to an euthyroid state, with minimal risk of complications. The relapse rate of the disease can reach up to 80 %, using conservative treatment. The radioiodine ablation is relatively simple, non-invasive, effective and cheap. There are special indications for surgical treatment. Indications for surgical treatment: 1) large goiter (the volume of the thyroid gland is more than 45 ml); 2) frequent recurrences of thyrotoxicosis and failure of the drug and RIT; 3)malignancy of goiter; 4) allergic and toxic (leukopenic) reactions to thyreostatics. Patients with Graves’ disease should referred to a specialized center with multidisciplinary team.

Bearing Scuffing Detection and Condition Monitoring Using Virtual Instrumentation

2014 ◽  
Vol 657 ◽  
pp. 604-608 ◽  
Author(s):  
Carmen Bujoreanu ◽  
Florin Breabăn
Keyword(s):  
Condition Monitoring ◽  
Virtual Instrument ◽  
Friction Torque ◽  
Diagnostic Methods ◽  
Virtual Instrumentation ◽  
Friction Forces ◽  
Data Acquisition Board ◽  
Bearing Condition Monitoring ◽  
Braking Torque ◽  
Vibration Signature

Bearing condition monitoring confronts the most machine users. Diagnostic methods used to include bearing problems represent one of the most important challenges. The scuffing phenomenon initiation of the bearing elements produces an important increase in the vibration level and can be emphasized by the analysis of the bearing friction forces which are the most sensitive indicator of the bearing failure. Commonly used technique for damage detection is the vibration signature analysis that must be carefully utilized in conjunction with the friction torque monitoring through the strain gauges measurements. In order to detect the scuffing onset, the paper presents an experimental setup for the scuffing tests performed on a 7206 ball bearing. A virtual instrument monitoring the friction force respectively the braking torque was created. An accelerometer captures the signal from the bearing outer ring then it is processed using PCI-4451 National Instruments data acquisition board and LabVIEW soft.

scholarly journals New Approach, Taking into Account Elastic and Inelastic Processes, for Transport Properties of a two Temperature Plasma

1985 ◽  
Vol 40 (9) ◽  
pp. 885-891 ◽  
Author(s):  
C. Bonnefoi ◽  
J. Aubreton ◽  
J.-M. Mexmain
Keyword(s):  
Thermal Conductivity ◽  
Electron Temperature ◽  
Plasma Electron ◽  
Temperature Plasma ◽  
Heavy Particles ◽  
New Approach ◽  
Definition Of ◽  
Thermal Conductivity Λ ◽  
Two Temperature ◽  
Inelastic Processes

Abstract We have developed a modified Chapman-Enskog method for a two-temperature partially ionized plasma: electron temperature (Te) and heavy particles temperature (Th). We introduce a new definition of the diffusion forces and then calculate the reactive thermal conductivity λR.

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