Changes In Plasma Parameters Research Articles

Tunable biasing magnetic field design of ferrite tuner for ICRF heating system in EAST

Ion cyclotron range of frequency (ICRF) heating has been used in tokamaks as one of the most successful auxiliary heating tools and has been adopted in the EAST. However, the antenna load will fluctuate with the change of plasma parameters in the ICRF heating process. To ensure the steady operation of the ICRF heating system in the EAST, fast ferrite tuner (FFT) has been carried out to achieve real-time impedance matching. For the requirements of the FFT impedance matching system, the magnet system of the ferrite tuner (FT) was designed by numerical simulations and experimental analysis, where the biasing magnetic circuit and alternating magnetic circuit were the key researched parts of the ferrite magnet. The integral design goal of the FT magnetic circuit is that DC bias magnetic field is 2000 Gs and alternating magnetic field is ±400 Gs. In the FTT, E-type magnetic circuit was adopted. Ferrite material is NdFeB with a thickness of 30 mm by setting the working point of NdFeB, and the ampere turn of excitation coil is 25 through the theoretical calculation and simulation analysis. The coil inductance to generate alternating magnetic field is about 7 mH. Eddy-current effect has been analyzed, while the magnetic field distribution has been measured by a Hall probe in the medium plane of the biasing magnet. Finally, the test results show the good performance of the biasing magnet satisfying the design and operating requirements of the FFT.

Optimizing Process Parameters for Plasma Assisted Atomic Layer Deposition

Plasma assisted atomic layer deposition (PA-ALD) is a low temperature conformal layer-by-layer deposition technique that is based on a pair of self-terminating and self-limiting gas-surface half-reactions, in which at least one half-reaction involves species from a plasma. This approach generally offers the benefit of substantially reduced growth temperatures and greater flexibility in tailoring the gas phase chemistry to produce varying film characteristics. The flexibility and lower growth temperatures that plasmas provide come at the cost of a complex array of process variables that often require great care on the part of the user. In response to this challenge, this work focuses on the use of plasma diagnostics to inform the choice of process conditions for PA-ALD systems. In this work we employ optical emission spectroscopy and charged particle collectors to characterize a Fiji 200 (Ultratech/CNT) PA-ALD tool. In particular, we assess the total ion flux reaching the substrate surface and the relative fractions of atomic and molecular species generated in the plasma under a variety of pressures and gas input flow fractions in the context of PA-ALD of AlN and Ga2O3films. Changes in plasma parameters are then linked with changes in film characteristics. ________________________________ * This work supported by the Naval Research Laboratory Base Program

Chronic exposure of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces an obesogenic effect in C57BL/6J mice fed a high fat diet

Contaminant involvement in the pathophysiology of obesity is widely recognized. It has been shown that low dose and chronic exposure to endocrine disruptor compounds (EDCs) potentiated diet- induced obesity. High and acute exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a persistent organic pollutant (POP) and an EDC with anti-estrogenic property, causes wasting syndrome . However at lower doses, the TCDD metabolic effects remain poorly understood. We investigated the obesogenic effect during chronic exposure of TCDD at 1μg/kg body weight (bw)/week in adult C57BL/6J mice fed with a high fat diet (HFD) and exposed from 10 to 42 weeks old to TCDD or equal volume of vehicle by intragastric gavage. Under these conditions, TCDD was obesogenic in adult mice (7% in males and 8% in females), which was linked to fat mass. A sex effect was observed in the fat mass distribution in adipose tissue and in the hepatic triglyceride content evolution. In visceral fat pad weight, we observed a decrease (11%) in males and an increase (14%) in females. The hepatic triglyceride content increase (41%) in females only. TCDD failed to induce any change in plasma parameters regarding glucose and lipid homeostasis. Messenger ribonucleic acid (mRNA) levels involved in adipose tissue and hepatic metabolism, inflammation, xenobiotic metabolism and endocrine disruption were differently regulated between males and females. In conclusion, these results provide new evidence that dioxin, a POP and EDC can be obesogenic for adult mice with multi-organ effects.

Hysteresis and fast timescales in transport relations of toroidal plasmas

This article assesses current understanding of hysteresis in transport relations, and its impact on the field. The rapid changes of fluxes compared to slow changes of plasma parameters are overviewed for both core and edge plasmas. The modulation ECH experiment is explained, in which the heating power cycles on-and-off periodically, revealing hysteresis and fast changes in the gradient–flux relation. The key finding is that hystereses were observed simultaneously in both the the gradient–flux and gradient–fluctuation relations. Hysteresis with rapid timescale exists in the channels of energy, electron and impurity densities, and plausibly in momentum. Advanced methods of data analysis are explained. Transport hysteresis can be studied by observing the higher harmonics of temperature perturbation in heating modulation experiments. The hysteresis introduces the term , which depends on the harmonic number m in an algebraic manner (not exponential decay). Next, the causes of hysteresis and its fast timescale are discussed. The nonlocal-in-space coupling works here, but does not suffice. One mechanism for ‘the heating heats turbulence’ is that the external source S in phase space for heating has its fluctuation in turbulent plasma. This coupling can induce the direct input of heating power into fluctuations. The height of the jump in transport hysteresis is smaller for heavier hydrogen isotopes, and could be one of the origins of isotope effects on confinement. Finally, the impacts of transport hysteresis on the control system are assessed. Control systems must be designed so as to protect the system from sudden plasma loss.

Influence of the geometry system on the effectiveness of polarimetric measurements in thermonuclear plasma diagnostics

Simulations are undertaken using the angle variable technique (AVT) to study changes of the polarimetry state of an electromagnetic wave passing through a thermonuclear plasma in the poloidal plane. The first section analyses the changes in polarization state depending on the angle at which a test beam is sent for a set of fixed plasma parameters Subsequently, for a given geometry, numerical calculations are used to verify the influence of changes in various parameters of plasma (plasma density, current density, the safety factor profile) on the state of polarization of the test beam. All numerical calculations were being performed for ITER relevant plasma parameters. It should be emphasized that due to the different geometries in the present work both Faraday and Cotton-Mouton effect are taken into account.

Energy partitioning and its influence on surface scatter coefficients within fluorinated inductively coupled plasmas

Energy partitioning for molecules formed from fluorinated plasma systems has been measured using laser-induced fluorescence, optical emission, and broadband absorption spectroscopies. For the two radicals discussed here, SiF in tetrafluorosilane plasmas, and CF in CxFy-type fluorocarbon plasmas, high electronic excited state vibrational temperatures, TV, suggest that vibrational modes are preferentially excited over other degrees of freedom. In CxFy plasma systems, rotational temperatures, TR, for the radicals equilibrate to the plasma gas temperature and remain independent of changing plasma parameters. TR for ground state CF2 molecules are elevated in comparison to the excited state radical. Translational temperatures (TT) and TR for SiF increase concomitantly with increasing vibrational temperatures, suggesting that a vibrational-translational energy exchange mechanism is the preferred pathway for vibrational relaxation in these molecules and rotational degrees of freedom are more easily thermalized compared to vibrational modes. Using the imaging of radicals interacting with surfaces technique, surface scattering coefficients measured for each radical show a strong correlation with the associated TV, with little dependence upon TR or TT. Ultimately, this work provides fundamental, molecular-level understanding of fluorinated plasma systems and helps to reveal the complex interactions between the distribution of energy within the plasma and its influence at a surface.

İNDÜKSİYON EŞLENİKLİ ARGON PLAZMASINDA AKIŞ DEBİSİ VE BOBİN LOKASYONUNUN SİSTEM ÇALIŞMA PARAMETRELERİNE ETKİSİ İLE İLGİLİ SİMÜLASYONLAR

The usage areas of the plasmatron has been increasing due to the very high level of temperature which they can reach. They are used widely in the plasma-wind tunnels to create the atmospheric test conditions of high velocity aircrafts and spacecrafts while entering atmosphere. Additionally, most efficient coal and bio-mass burning also, syngas production from burning of the coal and biomass can be achieved with the high temperature plasmatrons. They are also used in the tests of high temperature resistance materials, plasma metallurgy and related scientific researches. The usage of simulation is very important to determination and verification for technical requirements of a plasma and plasmatron system before it’s production, the time, cost and technical risks can be minimized before investing money to the production and development by simulating the related plasma system. In this work, a system that is consisted of inductive coupled plasma (ICP) is investigated by making related computer simulations. Investigated simulations are gas flow simulation, heat transfer simulation and plasma simulation and, these simulations are performed as coupled. In these simulations, the RF frequency is chosen as 13.56 MHz and vacuum pressure is chosen as 1 Torr. This vacuum level is selected appropriately for atmospheric re-entry experimental conditions. The mass flow rate is adjusted as a low and a high level, Q 1 =3 mg/s and Q 2 = 90 mg/s respectively. With these setting the changes of flow, heat and plasma parameters are investigated. Totally, 7 different chemical reaction is added to the realized simulations. The magnetic field distribution, the electric field induced from this magnetic field, the magnetic field magnitude, flow temperature distribution, convective heat transfer distribution, plasma gas velocity field, plasma gas pressure distribution and plasma electron density distribution is calculated in these simulations and, these results are compared for the different gas mass flow rate. Finally, the location of the coils which gives the RF electrical energy to the ICP plasma are slid to where the plasma gas is leaving from the geometry which respect to symmetry axis-z. The simulations are performed when the coils are in the middle and in the gas exit of the geometry. In these two different configurations, the power which this system is taken and mass flow rates are kept the same. These values are 3500 Watt and 90 mg/s respectively. Afterward with the change of the coils location, the plasma electron temperature and plasma gas temperature are investigated for 1-D and 2-D distribution and they are compared for discussion.

Evaluation of plasma sphingosine 1-phosphate, hepcidin and cardiovascular damage biomarkers (cardiac troponin I and homocysteine) in rats infected with brucellosis and vaccinated (Rev-1, RB-51).

Brucellosis is known as one of important zoonosis. Studying the histological and biochemical effects of the disease could help to increase our knowledge about it. The aim of the present study was to evaluate changes of plasma parameters after intraperitoneal injection of two species of Brucella (Brucella melitensis and Brucella abortus) and two vaccines (Rev-1, RB-51) in the rat. Forty male rats were divided into five groups (n=8 in each group). Two groups received suspensions of Brucella abortus and Brucella melitensis and two other groups were injected intraperitoneally with two mentioned vaccines and the last group received only distilled water. The results showed a significant increase in sphingosine 1-phosphate, Malondialdehyde, hepcidin, homocysteine, cardiac troponin I and copper levels and a considerable decrease in the levels of iron and zinc (P≤0.01) in infected groups compared to the control animals. In vaccinated groups, hepcidin was increased but other parameters were not changed in comparison to the control group. It can be concluded that increase of homocysteine and cardiac troponin I in brucellosis could be a warning for cardiac adverse effects. Besides, increase of sphingosine 1-phosphate probably indicates its stimulant and modulatory effects in anti- Brucellosis biochemical pathways of the host.

Analysis of Dissociation Mechanism of CO2 in a Micro-Hollow Cathode Discharge**Supported by the National Natural Science Foundation of China under Grant Nos 11575019 and 11275021.

Considering the feature of distributions of parameters within the micro-hollow cathode discharge, we use a simple method to separate the sheath region characterized by drastic changes of plasma parameters and the bulk plasma region characterized by smooth changes of plasma parameters. A zero-dimensional chemical kinetic model is used to analyze the dissociation mechanism of CO2 in the bulk plasma region of a micro-hollow cathode discharge and is validated by comparisons with previous modeling and experimental results. The analysis of the chemical kinetic processes has shown that the electron impact dissociation and heavy species impact dissociation are dominant in different stages of the micro-hollow cathode discharge process for a given applied voltage. The analysis of energy consumption distributions under different applied voltages reveals that the main reason of the conversion improvement with the increase of the applied voltage is that more input energy is distributed to the heavy species impact dissociation.

Transport hysteresis of core plasma, isotope effect, and H-mode physics

This article assesses the understanding of and impact by the hysteresis in transport relation. The rapid changes of fluxes compared to slow changes of plasma parameters are overviewed for both edge barrier and core plasmas. The theoretical approaches to understanding the direct influence of heating power on turbulent transport are addressed. Based on this new theoretical framework, the ‘isotope effect’ of plasma confinement time is discussed. A trial explanation is given for this unresolved mystery in plasma confinement. The advanced data analysis method to research the hysteresis in gradient-flux relation is explained.

Curcumin alleviates ischemia reperfusion-induced acute kidney injury through NMDA receptor antagonism in rats

Objective: The present study investigated the role of N-methyl-d-aspartate (NMDA) receptors in curcumin-mediated renoprotection against ischemia reperfusion (I/R)-induced acute kidney injury (AKI) in rats.Methods: Rats were subjected to bilateral renal I/R (40 min I, 24 hours R) to induce AKI. Kidney injury was assessed by measuring creatinine clearance, blood urea nitrogen, plasma uric acid, potassium level, fractional excretion of sodium, and macroproteinuria. Oxidative stress in renal tissues was assessed by measuring myeloperoxidase activity, thiobarbituric acid reactive substances, superoxide anion generation, and reduced glutathione content. Hematoxylin & eosin staining was done to assess histological changes in renal tissues. Curcumin (30 and 60 mg/kg) was administered one hour before subjecting rats to AKI. In separate groups, NMDA receptor agonists, glutamic acid (200 mg/kg), and spermidine (20 mg/kg) were administered prior to curcumin treatment in rats followed by AKI.Results: I/R-induced AKI was demonstrated by significant change in plasma and urine parameters along with marked increase in oxidative stress and histological changes in renal tissues that were aggravated with pretreatment of glutamic acid and spermidine in rats. Administration of curcumin resulted in significant protection against AKI. However, glutamic acid and spermidine pretreatments prevented curcumin-mediated renoprotection.Conclusion: It is concluded that NMDA receptor antagonism significantly contributes towards curcumin-mediated protection against I/R-induced AKI.

Optimization of plasma treatment variables for the improvement of carbon fibres/epoxy composite performance by response surface methodology

The purpose of the current work was to investigate the effect of oxygen plasma treatment of carbon fibre on the interfacial adhesion in carbon fibre/epoxy composites. The adhesion between the carbon fibre and matrix was examined by interlaminar shear strength (ILSS). It was observed that the composites prepared from plasma treated carbon fibre had higher ILSS compared with untreated fibres. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were employed to study the changes in the surface morphology of carbon fibres and the fracture of carbon fibre/epoxy composite before and after plasma treatment. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) analysis indicated that the plasma process created hydroxyl and carboxyl groups at the surface of carbon fibres. An experimental design with the identified process parameters namely, treatment time, power and flow rate of oxygen gas was followed. Experiments were performed according to the design in order to optimize the plasma variables by response surface methodology (RSM) using Box Behnken design. A second-order polynomial model was developed to predict the ILSS of carbon fibre composites in relation with the changes in plasma parameters. The process conditions were optimized with the quadratic model and the most efficient conditions were confirmed by the empirical results.

Spectroscopic and morphological studies of laser ablated silver

The spectroscopic and morphological studies of silver has been investigated after irradiation of Nd:YAG laser by employing Laser Induced Breakdown Spectroscopy (LIBS) and Scanning Electron Microscope (SEM) analyses. Silver targets were exposed to various laser fluences ranging from 5.2Jcm−2 to 41.7Jcm−2 under ambient environment of argon at a pressure of 100Torr. LIBS analysis revealed that when the laser fluence was increased from 5.2Jcm−2 to 10.4Jcm−2, an increasing trend for both electron temperature and electron number density of plasma was observed due to enhanced energy deposition. Afterwards, with increasing fluence from 10.4Jcm−2 to 15.6Jcm−2, a decreasing trend was achieved which was attributed to the shielding effect. With further increase in fluence from 15.6Jcm−2 to a maximum value of 41.7Jcm−2, a saturation region was achieved and insignificant changes in both plasma parameters were observed. This saturation is explainable on the basis of the formation of a self-regulating regime. SEM analysis revealed the formation of flakes and ridges on the surface of silver at the lowest fluence of 5.2Jcm−2. For increased fluences ranging from 10.4Jcm−2 to 41.7Jcm−2, distinct and unorganized melted channels were the dominant features. However, at a maximum fluence of 41.7Jcm−2, micro and nano crystallites of lamellar (tabular) shape were also formed. At peripheral ablated areas, flakes, cavities, cones and craters with multiple ablated layers were formed. The modifications in surface morphology of laser-ablated silver have been correlated with plasma parameters.

Effect of magnetic field on laser-induced breakdown spectroscopy of graphite plasma

The effect of transverse magnetic field on laser-induced breakdown spectroscopy of graphite plasma as a function of fluence has been investigated. Graphite targets were exposed to Nd:YAG (1064 nm, 10 ns) laser pulses at various laser fluences ranging from 0.4 to 2.9 J cm−2 under two different environment of air and Ar at a pressure of 150 and 760 torr. A transverse magnetic field of strength 0.5 tesla was employed by using permanent magnets. It is revealed that due to the presence of the magnetic field the emission intensity, electron temperature and number density of graphite plasma have been increased at all fluences and for all environmental conditions. The enhancement in plasma parameters is attributed to magnetic confinement effect and Joule heating effect. Initially by increasing the fluence from 0.4 to 1.5 J cm−2 (in air) and 0.4 to 1.8 J cm−2 (in Ar), the emission intensity, electron temperature and number density have been increased and have attained their maximum values. Further increase in fluence was responsible for the decreasing trend in all plasma parameters. More increase in fluence (beyond 1.8 J cm−2 in case of air and 2.2 J cm−2 in case of Ar) up to a maximum value of 2.9 J cm−2, the saturation or self-sustained regime was achieved, which is responsible for insignificant changes in plasma parameters. The value of plasma parameter “β” was also evaluated analytically, and it was less than one for all conditions (fluences as well as environments), which confirmed the existence of confinement effect.

Characteristics of the resonant instability of surface electrostatic-ion-cyclotron waves in a semi-bounded warm magnetized dusty plasma

The influence of magnetic field and dust rotation on the resonant instability of surface electrostatic-ion-cyclotron wave is kinetically investigated in a semi-bounded warm magnetized dusty plasma. The dispersion relation and the temporal growth rate of the surface electrostatic-ion-cyclotron wave are derived by the specular-reflection boundary condition including the magnetic field and dust rotation effects. It is found that the instability domain decreases with an increase of the rotation frequency of elongated dust grain. It is also found that the dependence of the propagation wave number on the temporal growth rate is more significant for small ion cyclotron frequencies. In addition, it is shown that the scaled growth rate increases with an increase of the strength of magnetic field. The variation of the domain and magnitude of temporal growth rate due to the change of plasma parameters is also discussed.

Influence organic connections on contractive activity of lymph node

This article shows that in influence organic connections rats there wasa decrease of the thoracic lymph duct. Influence of organic toxic substanceis studied on the contractive function of the isolated lymph nodes for rats.It is shown in experiments, that infringement in biochemical content ofa lymph and plasma of blood have been observed, represses contractiveactivity of lymph nodes. Lymph nodes are executed in an organism by numerous functions and most essential from them – it depositing, transport,barrier, exchange et al. In extreme situations lymph nodes can deposit aconsiderable volume внеклеточной at poisoning. The experiments showthat the long-term poisoning of rats by causes changes in biochemicalcomposition and physicochemical parameters of lymph and blood plasma. The was reduction in the lymph flow from the intestinal lymphaticvessel were observed. A decrease in the viscosity of the dry residue ofblood plasma and lymph after poisoning at rats organic toxic substanceswas recorded. There was a reliable decline of maintenance in total proteincontent of blood plasma and lymph. These data testify to reduction to theexchange function of the lymphatic system. Under the poisoning by substances there were observed the violation of the rheological properties ofblood and lymph, the increase in viscosity, and accelerated clotting whichdeteriorated the fluidity of both blood and lymph.Key words: lymph, lymph dynamics, lymph nodes, contractile activity

Acid and re-esterified rapeseed oils as alternative vegetable oils for rainbow trout diets: Effects on lipid digestibility and growth

The present study aimed at evaluating the effects of dietary acid and re-esterified rapeseed oils as alternatives to native vegetable oils (VO) on growth performance and feed utilization in rainbow trout. Acid oils are a free fatty acid (FFA)-rich by-product from the refining of VO and re-esterified oils are the final product of a chemical esterification process between acid oils and glycerol. Because re-esterified oils have a high content of mono- and di-acylglycerols (MAG and DAG), known for being good emulsifiers, a higher nutritive value than that of the native and the acid oils might be expected. A 72-day feeding trial where triplicate groups of rainbow trout were fed eight experimental diets formulated to contain 15% of a native, a re-esterified and an acid rapeseed oil, in addition to a 5% of fish oil (FO), was carried out. Diets with the native or the re-esterified oils blended with the acid oil were also studied. A commercial fish oil was used for the control diet. Fish fed rapeseed acid and re-esterified oil diets (RA and RE, respectively) showed high fat and total fatty acid apparent digestibility coefficients (ADC) (RA: 90.5±0.3%, RE: 92.5±1.0% for total fat and RA: 95.7±0.1%, RE: 95.8±0.2% for total fatty acids). However, the lowest total fatty acid ADC was that obtained in animals fed RA, which was significantly lower (P<0.05) than that of fish fed the rapeseed native oil diet (RN: 96.7±0.1%). No significant differences in final weight were obtained between fish fed RA (375.9±2.9g) and RE (381.5±11.1g) and those fed RN (393.7±6.1g), even though both values were significantly lower (P<0.05) than that of fish fed the control diet (411.1±3.3g). Nonetheless, fish fed diets including blends of the rapeseed acid and the re-esterified oils (RE/RA and RA/RE) had higher final weights (392.8±4.4 and 394.6±1.6, respectively) than those of RA and RE, although differences were not statistically significant. Furthermore, RA and RE diets did not produce relevant changes in plasma parameters or in the morphology of liver and intestine of fish. Therefore, the inclusion of rapeseed acid and re-esterified oils along with a 5% of FO in aqua feeds does not seem to have negative effects on fat and fatty acid digestibility, growth, plasma parameter or morphology of liver and intestine in rainbow trout. However, before recommending their use, further studies regarding their effects on the final composition and quality of fillets should be carried out. Statement of relevanceRe-esterified and acid rapeseed oils could be included in diets for rainbow trout as economically advantageous sources with no negative results in fat and fatty acid digestibility, plasma parameters and morphology of liver and intestine.

Fine structure of modal focusing effect in a three dimensional plasma-sheath-lens formed by disk electrodes

Modal and discrete focusing effects associated with three-dimensional plasma-sheath-lenses show promising potential for applications in ion beam extraction, mass spectrometry, plasma diagnostics and for basic studies of plasma sheath. The ion focusing properties can be adjusted by controlling the geometrical structure of the plasma-sheath-lens and plasma parameters. The positive and negative ion kinetics within the plasma-sheath-lens are investigated both experimentally and theoretically and a modal focusing ring is identified on the surface of disk electrodes. The focusing ring is very sensitive to the sheath thickness and can be used to monitor very small changes in plasma parameters. Three dimensional simulations are found to be in very good agreement with experiments.

Laser-induced breakdown spectroscopy analysis of human deciduous teeth samples.

Laser-induced breakdown spectroscopy (LIBS) analysis of human deciduous teeth has been performed by employing Nd:YAG laser (1064 nm, 10 ns) for the evaluation of plasma parameters as well as elemental analysis. The plasma parameters, i.e., electron temperature and electron number density of laser-induced teeth plasma at various fluencies, have been evaluated. Both parameters show an increasing trend up to a certain value of laser fluence, i.e., 2.6 J/cm(2). With further increase in laser fluence up to a value of 3.9 J/cm(2), a decreasing trend is observed which is due to shielding effect. With further increase in laser fluence up to a maximum value of 10.5 J/cm(2), the insignificant changes in plasma parameters are observed which are attributed to saturation phenomenon governed by self-regulating regime. Emission spectroscopy results exhibit that laser fluence is the controlling factor for both plasma parameters. The elemental analysis was also performed at constant laser fluence of 2.6 J/cm(2) by evaluating the variation in detected elemental concentration of Ca, Fe, Sr, Zn, and Pb in three different parts of human teeth, i.e., enamel, dentine, and cementum. The lower concentration of Ca as compared to the standard values of CaCO3 (self-fabricated pellet) reveals that enamel is the most deciduous part of the human teeth. However, at the same time, it is also observed that the highest concentration of micro minerals is also found in enamel, then in dentine, and lowest in cementum. Carious or unhealthy tooth is identified by enhanced concentration of micro minerals (Pb, Sr, Zn, and Fe). The highest concentration of micro minerals as compared to other parts of teeth (dentine and root cementum) and lower concentration of Ca as compared to standard CaCO3 pellet in enamel confirm that enamel is the most deciduous part of the teeth.

Abrupt reversal of convective flow of carbon impurity during impurity-hole formation on the LHD

Time evolution of carbon density during impurity-hole formation is observed on the Large Helical Device (LHD) to study the dynamic behaviors of the carbon impurity flux. The flux of carbon impurity changes from inward to outward without significant change of plasma parameters in the plasma with a steep gradient of ion temperature. It is also observed that the flux of carbon impurity changes from outward to inward without significant change of plasma parameters at the termination of the impurity hole.