Discharge Conditions Research Articles

Blackberry Seeds-Derived Carbon as Stable Anodes for Lithium-Ion Batteries.

The suitability of biocarbons derived from blackberry seeds as anode materials in lithium-ion batteries has been assessed for the first time. Blackberry seeds have antibacterial, anticancer, antidysentery, antidiabetic, antidiarrheal, and potent antioxidant properties and are generally used for herbal medical purposes. Carbon is extracted from blackberries using a straightforward carbonization technique and activated with KOH at temperatures 700, 800, and 900 °C. The physical characterization demonstrates that activated blackberry seeds-derived carbon at 900 °C (ABBSC-900 °C) have well-ordered graphene sheets with high defects compared to the ABBSC-700 °C and ABBSC-800 °C. It is discovered that an ABBSC-900 °C is mesoporous, with a notable Brunauer-Emmett-Teller surface area of 65 m2 g-1. ABBSC-900 has good electrochemical characteristics, as studied under 100 and 1000 mA g-1 discharge conditions when used as a lithium intercalating anode. Delivered against a 500 mA g-1 current density, a steady reversible capacity of 482 mA h g-1 has been achieved even after 200 cycles. It is thought that disordered mesoporous carbon with a large surface area account for the improved electrochemical characteristics of the ABBSC-900 anode compared to the other ABBSC-700 and ABBSC-800 carbons. The research shows how to use a waste product, ABBSC, as the most desired anode for energy storage applications.

Cooling performance of a Li-ion cylindrical battery pack with liquid circulating pipes embedded in phase change material

In global efforts to reduce carbon emissions from conventional IC-engine-powered vehicles, several countries have taken steps to adopt electric vehicles (EVs) as alternate transport options. Lithium-ion batteries are widely used as power sources and a battery thermal management system (BTMS) is needed to ensure that the battery operates within the optimal operating temperature. In this study, the battery module is designed to have a single inlet and outlet as well as provisions for supplying and removing coolants on the same side. This facilitates easier placement of systems considering the constraints of electric vehicles. The hybrid cooling system is proposed utilizing the effectiveness of the phase change material in addition to the active mode of liquid cooling for twenty-five 18650 Li-ion batteries arranged in 5S5P pack configuration with a resultant target capacity of 12500 mAh and 18 V. The hybrid battery cooling systems are designed in three configurations based on the number of water-circulating pipes embedded in a phase change material (PCM) container: 4V3H, 6V5H, and 8V7H where V and H represent vertical and horizontal pipes. Detailed procedures have been included for the structural design and realization of the hybrid cooling system. With the proposed hybrid cooling systems, the maximum battery pack temperature could be restricted below 43 °C when the battery packs were subjected to 4C discharge conditions at an ambient temperature of 35 °C for a 4C3H system. The maximum temperature non-uniformity was found less than 0.86 °C. A battery pack operating at a higher ambient temperature of 40 °C, the effective use of PCM and water circulating tubes keeps the maximum battery temperature below 45 °C and maximum temperature non-uniformity below 0.75 °C.

Optimal discharging of solar driven sorption thermal battery for building cooling applications

In this study, optimal discharge conditions of sorption thermal battery (STB) are determined for stable supply of the building cooling load based on different load patterns. Parametric analysis is conducted to ascertain the influence of heat source temperature and the mass flow rate ratio between the solution and the heat transfer fluid on the performance of the STB. The maximum values of energy storage density (ESD) and coefficient of performance (COP) are estimated as 207.73 kWh/m3 and 0.74, respectively. The daily transient behaviors of STB are examined in detail, and the optimal solution charge and the solution flow rate are quantified based on the building types (residential, hospital, hotel, and office). For a building with an air conditioning floor area of 181.63 m2, the most suitable cooling load response is observed in the hotel scenario. The minimum deviated cooling output from the building load is 8.69%. Concurrently, COP and ESD are estimated of 0.69 and 101.99 kWh/m3. This paper demonstrates the cooling load responsiveness and optimal operating point of STB based on building load pattern. Additionally, a dimensionless number is defined to generate the discharge trend and enable to predict COP and ESD.

SOL impurity transport analysis with SONIC code with a kinetic effect on a thermal force transport model in JT‐60U

AbstractThe latest version of the SONIC code with the extended thermal force model that is capable to treat collisionality dependence of the force has been applied to the interpretative simulation of L‐mode discharge of JT‐60 U to investigate the impact of kinetic correction of the thermal force on the scrape‐off layer (SOL) plasma properties. As a first attempt, we have selected an L‐mode attached discharge #39090 (Ip = 1.6 MA, Bt = 3.1 T, and PNBI = 4.5 MW), where = 2.08 × 1019 m−3, = 0.392 with deuterium plasmas. It has been found that the peak values of SOL impurity density are reduced by a factor of 2, with the kinetic correction, because the thermal force is reduced by the low collisionality of SOL plasma between the X‐point and the (inner and outer) midplane. On the other hand, the profiles near the divertor plates are unaffected by the kinetic correction due to the highly collisional condition. The kinetic correction is found more pronounced for the higher charge states impurity due to the charge dependence of the parallel impurity force balance. Overall effects due to the kinetic correction on the total impurity radiation and the divertor heat load are confirmed to be a few % in the present discharge condition of JT‐60U.

Domain-alignment multitask learning network for partial discharge condition assessment with digital twin in gas-insulated switchgear

Deep-learning-driven methods have made great progress in the condition assessment of partial discharge (PD) which including diagnosis and location in gas-insulated switchgear (GIS). However, these methods perform diagnosis and location as two separate tasks and ignore the coupling relationship. In addition, these methods all require obtaining sufficient samples to develop models, and the model becomes ineffective when there is a significant difference in sample distribution. Therefore, we propose a novel domain-alignment multitask learning network (DAMTLN) for condition assessment including diagnosis and location assisted by digital twin. Firstly, a digital virtual model is established to assist the actual condition assessment of GIS PD. Then, a novel multitask network is constructed to mine the coupling relationship between the two tasks. Finally PD condition assessment guided by a digital twin model are achieved via a combination of local-maximum-mean-discrepancy-based and adversarial -based domain adaptation, in which fine-grained information on each category is captured. Experimental results show that the proposed DAMTLN achieved a diagnostic accuracy of 98.73%, and the mean absolute error of location was 9.06 cm, which were significantly better than the results of other methods. The DAMTLN thus provides a new avenue for PD diagnosis and location driven by ‘data–physics’ coupling.

Sensitivity of small river channels in the North Carolina Piedmont to change in streamflow conditions, Atlantic Multi-decadal Oscillation, and land use/land cover change

Twenty-four years (1999–2022) of channel change is assessed using specific-gage analysis based on the United States Geological Survey (USGS) rating curve calibration data from thirteen sites (drainage area < 500 km2) to understand the sensitivity of discharge-specific stage (DSS) or its inverse, stage-specific channel capacity (SSCC) to streamflow regimes, hydroclimatological history, and land use in small Piedmont watersheds of North Carolina, USA. We compare observed channel changes to common streamflow and flood metrics, Atlantic Multi-decadal Oscillation Index (AMOI), and land use/land cover data using regression and correlation techniques to suggest drivers of change and infer sensitivity. In addition to interannual variability, our results at most sites reveal three coherent periods of DSS/SSCC variation at the sub-decadal scale as well as multidecadal trend variation. The magnitudes and frequencies of these changes indicative of potential sensitivity vary substantially amongst sites. The trendlines from the DSS plots for the full length of record indicate that six sites showed increased specific stage while the remaining seven sites showed either reduced or a near-zero change in specific stage. Coefficients of determination relating specific stage and the index of AMO are low (R2 = 0.14—0.38) with both positive and negative relationships exhibited. Multiple regression, coefficients of determination relating specific stage and average monthly discharge are more variable, ranging from 0.18 to 0.94. Both positive and negative correlations (r ≤ 0.7) are found between specific stage and basin land use/land cover intensity indices, although few are significant at 95 % confidence interval. Both qualitative observations and correlation analyses support inferences that drought and persistent low mean discharge conditions tend to increase discharge-specific stage values (decreasing SSCC), by aggradation of the bed and/or lower banks. At our sites, this may be responsible for a sub-decadal trend of increasing specific stage between roughly 2013 and 2018, followed by ongoing reductions over the subsequent period.

Impact on urban river water quality and pollution control of water environmental management projects based on SMS-Mike21 coupled simulation

To explore the impact of expanding Nanyang Sewage Purification Center (NSPC) on the main sewage discharge area of Bai River, we constructed a 2D hydrodynamic-water quality model based on surface water modeling system (SMS) and Mike21. Simulating three sewage discharge conditions in wet, normal, and dry season, we evaluated three indicators (COD, NH3-N, and BOD5) by the single-factor pollution index and provided recommendations for water environment management. The results showed that, maximum absolute error of water level was 0.08 m, percentage bias coefficient of COD, NH3-N and BOD5 were 19.3%, 16.2% and 23.1%, indicating the SMS and Mike21 coupling model was applicable; water quality of the assessment section were upgraded from the original class IV, V, V (Condition 1) to class IV, III, II (Condition 2) and class IV, III, III (Condition 3) in the wet, normal and dry season, indicating that NSPC's expansion had improved the water quality of the assessment section; as the primary pollutant, BOD5 concentration in the downstream was lower than the upstream, which was due to the dilution effect of river. Therefore, on the basis of expanding NSPC, we recommend to remediation of BOD5 by physical, chemical, and biological methods. This study broadens new ideas for the application of Mike21, and provide a reference for the prevention and improvement of river water pollution in urban areas.

On thermodynamics and heat and mass transfer aspects of CH4 adsorption onto coconut shell-based carbonaceous material

The current study investigates the equilibrium methane (CH4) adsorption capacity and the adsorption kinetics of a locally produced coconut shell-derived activated carbon (AC CARB 6X12 60) for pressure and temperatures ranging from 0 to 55 bar and -20 to 70 °C, respectively. The adsorption isotherms and kinetics are determined using an in-house developed adsorption test rig. A maximum methane adsorption uptake of 0.140 kg/kg is obtained at -20 °C and 40 bar pressure. The adsorption equilibrium isotherm data are fitted using Toth, Dubinin-Astakhov (DA), and Modified-DA isotherm models. Afterwards, the kinetics study is done considering pseudo first order, second order, Elovich, and intra-particle diffusion models. In continuation, based on the DA isotherm model, Clausius Clapeyron relation, and Maxwell's relations, the expressions for the crucial thermodynamic parameter of adsorbed phase, i.e., isosteric heat of adsorption, specific heat capacity, enthalpy, and entropy is derived, and same is estimated using DA isotherm parameters. Additionally, the activated carbon's thermophysical properties (i.e., thermal conductivity, thermal diffusivity, and specific heat) are determined using the TPS 2500 S analyzer, which works on the hot-disk principle. Using the most suitable isotherm (DA) and kinetic model (pseudo second order), heat and mass transfer analysis is carried out on novel reactor configuration with an external cooling jacket, double row of cooling pipes with external longitudinal fins for methane storage using a 3D transient model in Comsol Multiphysics. The charge characteristics are studied for gas charging pressure varying from 1 to 50 bar and cooling fluid temperature of -20 to 70 °C. Iso-concentration contours are plotted to identify the pressure-temperature combination resulting in identical storage capacity (i.e., including both gaseous and adsorbed phases). Further simulations are carried out for constant pressure charging and constant flow discharge conditions to expound upon the effects of the dormancy period, gas charging pressure, and cooling/heating fluid temperature. 14% improvement in total discharge amount is obtained with a dormancy period between charging and discharging compared to no dormancy case.

Effect of discharge operation on thermal runaway incubation process of lithium-ion battery: An experimental study

As the most critical safety issue for lithium-ion batteries (LIBs), thermal runaway (TR) may occur during operation, but the characteristics of TR under such conditions are not clear yet. Hence, the TR processes are studied under discharge conditions in this work. Firstly, TR is investigated under thermal abuse coupled with discharge to obtain the critical parameters at the cell level, compared with the test without discharge operation, the onset temperature of TR shows significant changes based on the residual state of charge (SOC), but the maximum difference of TR incubation time is only about 3%. Subsequently, the effect mechanism of discharge on TR is analyzed by clarifying the heat source contribution of the cells, the heat generated by the cell becomes the main driving force of TR before the discharge ratio reaches its maximum value, and the difference in total heat accumulation is caused by the scale of exothermic side reactions of LIB under the influence of SOC. The lower the cell SOC, the more heat is generated by the cell itself to trigger TR. Lastly, the effectiveness of discharge to mitigate TR propagation also has been verified from various perspectives at the module level. The results are expected to provide a reference for the safe application of LIBs and TR disaster mitigation.

Hydraulic Relationship between Hulun Lake and Cretaceous Confined Aquifer Using Hydrochemistry and Isotopic Data

Hydraulic Relationship between Hulun Lake and Cretaceous Confined Aquifer Using Hydrochemistry and Isotopic Data

Hydro‐Sedimentary Processes of a Plunging Hyperpycnal River Plume Revealed by Synchronized Remote Imagery and Gridded Current Measurements

AbstractThe present knowledge of plunging hyperpycnal river plumes is mainly based on two‐dimensional (confined) laboratory experiments. Several hypotheses on three‐dimensional (unconfined) flow processes have been made, but not tested in situ. In this field study, the dominant three‐dimensional hydro‐sedimentary processes related to unconfined plunging were elucidated by synchronizing autonomous time‐lapse camera images with boat‐towed acoustic Doppler current profiler measurements. It was found that the flow field complies with two‐dimensional conceptualizations along the plume centerline. Perpendicular to the centerline, the plume slumped laterally due to its density excess and simultaneously converged laterally due to its vertical divergence. This combination led to a narrowing of the plume near the surface, resulting in a sediment‐rich triangle‐shaped pattern on the surface near the inflow, and a rather stable width near the bed. The formation of secondary flow cells transporting riverine water and suspended particulate matter (SPM) away from the plume near the bed, up toward the surface and back toward the plume near the surface, was revealed. An increase of the average SPM concentration and the SPM flux in the main flow direction indicates net sediment erosion under the investigated conditions of high discharge and sediment load. This suggests transient storage of sediment during conditions of lower discharge and sediment load, and high morphological activity in the plunging area. These findings allowed extending a classical conceptual plunging model to laterally unconfined sediment‐laden plunging inflows for conditions of well‐mixed ambient water in the plunging region and inflow densimetric Froude numbers exceeding 1, common in nature.

Reliability of reservoir inflow for supporting the operation simulation model of multi reservoir

This research intends to analyze the inflow reliability of the Tugu-Bagong multi-reservoir. The utilization of Tugu Dam is as follows: for fulfilling the irrigation water need of Ngasinan Irrigation Area an area is 1,200 ha, supplying 12 l/s of raw water, controlling the yearly flood in Trenggalek Regency with the discharge is 76.21 m3/s, as the potency of mini-hydro electrical generation (PLTM) in the amount of 0.40 MW, and as the tourism means. However, Bagong Dam, besides being utilized for flood control, is also utilized for supplying raw water, irrigation, and domestic water; for water resources conservation; and recreation or tourism. The methodology consists of collecting the rainfall data and watershed parameters like watershed area, infiltration coefficient each for dry and rainy seasons, retention coefficient, SMC value, etc.; to analyze the dependable discharge due to the rainfall analysis input in 4 discharge conditions: dry season discharge, low water discharge, normal water discharge, and sufficient water discharge. The result of inflow reliability is hoped to be able to support the operation simulation modeling of the Tugu-Bagong multi-reservoir.

A comparative DFT study on the adsorption properties of lithium batteries thermal runaway gases CO, CO2, CH4 and C2H4 on pristine and Au doped CdS monolayer

The thermal runaway gases, such as CO, CO2, CH4, and C2H4, will leak from the battery electrolyte when lithium batteries in extreme discharge or thermal runaway conditions. The structural properties, differential charge density (DCD), density of state (DOS), gas adsorption properties, desorption time, work function and front-orbit theory calculation of pristine and Au doped CdS monolayer are explored and compared by first-principle calculation. The adsorption energy of CO, CO2, CH4 and C2H4 on the surface of Au–CdS are –0.89 eV, –0.40 eV, –0.14 eV and –0.77 eV, respectively. After doping, the adsorption type of CO and C2H4 are chemical type. Partial density of states shows that the gas molecules react with doped precious metal atoms. The adsorption ability of Au–CdS can be ranged as CO>C2H4>CO2>CH4. C2H4 on the surface of Au–CdS can desorb within 10 s at room temperature. As a result, Au–CdS exhibits tremendous prospective application as CO or C2H4 gas sensor. This study demonstrates that the adsorption and sensing properties of CdS monolayer can be improved effectively by the introduction of precious metal.

Plasma characteristics and material erosion mechanism in multi-channel wire electrical discharge machining

Multi-channel wire electrical discharge machining (MC-WEDM) is an advanced and high-efficiency machining technology, but its material erosion mechanism remains unclear. In this study, dual-channel wire electrical discharge machining was utilized as a case study to investigate the impact of the plunging current on both the plasma characteristics and material erosion under complex discharge conditions. Force analysis was conducted on the charged particles in the plasma, revealing that the plunging current can influence the trajectory of the plasma by modifying the self-magnetic field. The particle tracking method was employed to simulate the motion of electrons, revealing that in MC-WEDM, electrons exhibited a larger and more uniform distribution. The evolution of the plasma within a single-pulse discharge was observed using high-speed photography technology, and the discharge signals collected from different channels were analyzed. It was observed that the plasma in MC-WEDM experienced more intense back-and-forth sweeping on the workpiece surface, facilitating the ejection of molten metal from the molten pool. The oscillating plasma exhibits a larger processing area and a more uniform distribution of energy, resulting in the formation of larger and shallower discharge craters. Furthermore, the influence of the amplitude and time point of the plunging current on the volume and area of the discharge craters was summarized. Finally, MC-WEDM significantly reduced the occurrence of holes and micro-cracks and exhibited a thinner recast layer in the continuous discharge experiment.

Quantification of sediment fluxes and intermittencies from Oligo–Miocene megafan deposits in the Swiss Molasse basin

AbstractThe conglomerates preserved in alluvial fans in the Swiss Molasse basin provide crucial insights into the sedimentary dynamics of these routing systems. In particular, the architectural trends and grain sizes of such deposits reveal information on the sediment fluxes and record variations in the intermittency — a proxy for the fan's activity — that indicate on the relative importance of tectonic or climatic controls on sediment production and transport. Here, we calculated intermittencies from sediment transport dynamics using the ratio between the long‐term average and the short‐term instantaneous unit sediment fluxes during bankfull discharge conditions. For this, we collected grain size data from three palaeo‐fan systems that were active through Oligo–Miocene times and that reveal preserved proximal–distal relationships. The three fan systems, which we term the western, central and eastern fans, show significant differences in their long‐term sediment budget but equivalent magnitudes of the sediment transport dynamics expressed through the intermittency factor. The eastern fan records a low long‐term sediment flux (5.7 km2 Myr−1), which needed the fan to be active during ca. 8 h yr−1 (intermittency factor of 0.89 × 10−3). The western fan reveals a higher long‐term sediment flux (16.2 km2 Myr−1), which could have accumulated during ca. 16 h yr−1 (intermittency factor of 1.83 × 10−3), thereby reflecting a more active system. The central fan records the largest long‐term sediment flux (40.3 km2 Myr−1), where ca. 57 h yr−1 of sediment transport would be required to deposit the supplied material (intermittency factor of 6.53 × 10−3), thus representing the most active system. By relating these characteristics to the regional exhumation history, we consider that the central fan mainly recorded the transient response of the Alpine surface to the break‐off of the European mantle lithosphere slab. Contrarily, the western and eastern fans were formed during the Alpine evolution when steady‐state conditions between uplift and erosion were reached and when sediment fluxes to the basin were lower. Despite differences in the tecto‐geomorphic and climatic boundary conditions, our data suggest that these Oligo–Miocene megafans could accomplish their mean annual sediment transport work within a few hours or days per year.

Hydrologic and Landscape Controls on Rock Weathering Along a Glacial Gradient in South Central Alaska, USA

AbstractRock weathering impacts atmospheric CO2 levels with silicate rock dissolution removing CO2, and carbonate dissolution, pyrite oxidation, and organic rock carbon oxidation producing CO2. Glacierization impacts the hydrology and geomorphology of catchments and glacier retreat due to warming can increase runoff and initiate landscape succession. To investigate the impact of these changes on catchment scale weathering CO2 balances, we report monthly samples of solute chemistry and continuous discharge records for a sequence of glacierized watersheds draining into Kachemak Bay, Alaska. We partition solute and acid sources and estimate inorganic weathering CO2 balances using an inverse geochemical mixing model. Furthermore, we investigated how solutes vary with discharge conditions utilizing a concentration‐runoff framework. We develop an analogous fraction‐runoff framework which allows us to investigate changes in weathering contributions at different flows. Fraction‐runoff relationships suggest kinetic limitations on all reactions in glacierized catchments, and only silicate weathering in less glacierized catchments. Using forest cover as a proxy for landscape age and stability, multiple linear regression shows that faster reactions (pyrite oxidation) contribute less to the solute load with increasing forest cover, whereas silicate weathering (slow reaction kinetics) contributes more. Overall, in glacierized catchments, we find elevated weathering fluxes at high runoff despite significant dilution effects. This makes flux estimates that account for dilution more important in glacierized catchments. Our findings quantify how glaciers modify the inorganic weathering CO2 balance of catchments through hydrologic and geomorphic forcings, and support the previous hypothesis that deglaciation will be accompanied by a shift in inorganic weathering CO2 balances.

Risk factors for hemorrhage in patients with long-term aspirin therapy undergoing emergency external ventricular drainage/intracranial pressure probe placement

BackgroundStudies have been inconclusive on the risk for hemorrhage in patients with a history of aspirin use who underwent emergency external ventricular drainage (EVD)/intracranial pressure (ICP) probe placement. The aim of this study was to explore hemorrhage-related risk factors in order to reduce the risk for hemorrhage in these patients. MethodsBetween July 2014 and July 2020, patients were retrospectively divided into EVD/ICP-related hemorrhage and non-hemorrhage groups. The collected data included age, gender, major diagnosis, medical history, imaging examinations, conventional coagulation test data, thromboelastography with platelet mapping (TEG-PM), surgical procedures and discharge conditions. ResultsIn total 94 patients, 21 in the hemorrhage group (15 males, 6 females) and 73 in the non-hemorrhage group (52 males, 21 females) were included. The majority of hemorrhages were recorded in EVD patients (19/21; 90.5%). Platelet AA pathway inhibition rate of ≥75% (sensitivity: 79.45% specificity: 52.38%) (P = 0.014) and SBP ≥125 mmHg (P = 0.006) were significantly related to hemorrhage. When the platelet AA pathway inhibition rate was ≥75% and the during-procedure SBP was ≥125 mmHg, the hemorrhage rate was significantly higher (83.3%) than with SBP <125 mmHg (6.7%) (P < 0.001). When the inhibition rate was <75%, there were no significant differences in the hemorrhage rates between the during-procedure SBP ≥125 mmHg group (17.2%) and the SBP <125 mmHg group (13.2%) (P > 0.05). Multivariate logistic regression analysis revealed that a platelet AA pathway inhibition rate ≥75% (OR = 5.183, 95% CI: 1.683–15.960) and during-procedure SBP ≥125 mmHg (OR = 4.609, 95% CI: 1.466–14.484) were independent risk factors for EVD/ICP-related hemorrhage. ConclusionPatients with long-term aspirin therapy, a platelet AA pathway inhibition rate ≥75% and during-procedure SBP ≥125 mmHg had a significantly higher risk of hemorrhage, which could be reduced by adjusting the SBP to <125 mmHg.

A CNN-SAM-LSTM hybrid neural network for multi-state estimation of lithium-ion batteries under dynamical operating conditions

Accurately estimating the state of charge (SOC), state of energy (SOE), and state of health (SOH) online is a critical and urgent concern in the management of lithium-ion batteries for electric vehicle applications, particularly in terms of safety and reliability. This paper develops a hybrid neural network, abbreviated as CNN-SAM-LSTM model, which combines a convolutional neural network, self-attention mechanism, and long-short term memory neural network to jointly estimate the state parameters of lithium-ion batteries, including SOC, SOE, and SOH. Additionally, a joint loss function considering homoscedastic uncertainty is developed to optimize weight adjustments for the training losses associated with the three state parameters. Experimental data collected under UDDS, BBDST and CC discharge conditions are employed to showcase the effectiveness of the proposed CNN-SAM-LSTM model. The results demonstrate that the proposed model is capable of simultaneously and accurately estimating SOC, SOE, and SOH for lithium-ion batteries under different dynamical operating conditions. Moreover, when applied to randomly segmented data, the proposed model exhibits robustness, effectively handling deviations from random discharge segments.

Isotope effects on transport characteristics of edge and core plasmas heated by neutral beam injection (NBI) in an inward shifted configuration at the Large Helical Device

Isotope effects have been investigated in Neutral Beam Injection (NBI) heated plasmas on the Large Helical Device with similar operational parameters between Hydrogen (H) and Deuterium (D) plasmas. Experimental results show that the global energy confinement has no significant dependence on the isotope mass under similar discharge conditions with nearly the same heating power, line-averaged density ( nˉe ) and magnetic field. For both electron and ion energy transport, the transport coefficients, which are obtained based on local power balance analysis, have analogous profiles between H and D dominant plasmas. For neoclassical χe and χi values, they are almost equal between H and D dominant plasmas in low nˉe discharges, whereas in high nˉe cases they are lower in H plasmas than those in D ones. At low nˉe , the electron and ion thermal transport in both H and D plasmas are dominated by neoclassical transport at a certain zone ( ρ≈0.6−0.85 ), while the anomalous transport process has primary effects in the remaining area, and the density fluctuations exhibit ion temperature gradient mode nature. With increase of nˉe , the anomalous transport becomes prevailing and the density fluctuations propagate along electron diamagnetic drift direction. Bispectral analysis reveals that the H plasma has stronger nonlinear coupling in edge density fluctuations in both low and high density discharges, which is probably due to that the D plasma has stronger damping rate for the nonlinear interaction of turbulence. For a comparative study, the present results have been compared with those observed in the ECRH discharges (Tanaka et al 2019 Nucl. Fusion 59 126040). The reasons for the similarities and dissimilarities between these two different heating manners are not clear yet. To unravel the underlying physics, essential inputs from theories and simulations are required.

Stability Valorization of Hydrofluoroolefine HFO-1336mzzE and Its Mixtures under Arc Discharge Conditions

Stability Valorization of Hydrofluoroolefine HFO-1336mzzE and Its Mixtures under Arc Discharge Conditions