Steady-state Parameters Research Articles

Research on new energy grid-connected load monitoring method based on the network analysis method

Abstract The steady-state characteristic parameters of the loads are used to identify new energy grid-connected loads using an event-based network analysis method in this paper. The analysis of interdependence among elements is done by studying the element layer and special structure of the network analysis method. Using the principle of limit relative ranking vector calculation, the supermatrix and weighting matrix of the ANP element layer are constructed, and the basic steps of ANP model weights are determined. The ANP-based load monitoring algorithm is evaluated by combining the load identification accuracy with the F-value. The results show that event detection algorithms are generally more than 70% accurate. 17 out of 18 times of identifying load events of computers can be correctly identified with an accuracy rate of 89.37%, 9 out of 10 times of identifying fluorescent lamps with an accuracy rate of 89.98%, and 14 out of 15 times of identifying microwave ovens with an accuracy rate of 92.75%. The new energy grid-connected load can also be detected by combining the harmonic content rate. The harmonic content rates when the desktop computer was turned on were 93.04%, 86.67%, 60.16%, 61.76%, and 23.46%, respectively. This study helps to improve the accuracy of new energy grid-connected load monitoring.

Olaparib plus Abiraterone for Metastatic Castration-resistant Prostate Cancer: Pharmacokinetics Data from the PROpel Trial

PROpel (NCT03732820) was a positive phase 3 trial that demonstrated a clinically significant improvement in radiographic progression-free survival with olaparib plus abiraterone versus placebo plus abiraterone in first-line metastatic castration-resistant prostate cancer. For a subset of PROpel patients, steady-state concentrations of olaparib, abiraterone, and Δ4-abiraterone were measured in blood samples collected before and at several time points after dose administration. The pharmacokinetics (PK) for each drug and metabolite were evaluated to determine whether any clinically relevant drug-drug interactions between olaparib and abiraterone occurred. The results demonstrate that steady-state PK parameters for olaparib and abiraterone in PROpel were comparable with those in monotherapy trials. Abiraterone steady-state exposures were similar between treatment arms. Δ4-Abiraterone had slightly lower steady-state exposures when abiraterone was administered in combination with olaparib. These results are consistent with a previous phase 2 study, supporting the conclusion that no clinically relevant PK-based drug-drug interactions occurred when olaparib and abiraterone were given in combination at their full monotherapy doses. Patient summaryWhen drugs are administered in combination, a key consideration is whether there are any interactions between the drugs that may affect their activity. We analyzed blood concentrations of olaparib and abiraterone in a subset of patients with prostate cancer from the PROpel trial to determine if there were interactions between these two drugs. We found that there was no significant effect on the profile of either drug when they were given together at the same doses used when each drug is given individually.

Experimental analysis of a compact cooling system containing an enhanced-surface spray heat sink

This paper examines the performance of a heat sink that combines an evaporator and an expansion device into a single component within a compact vapor compression refrigeration system designed for applications with high heat fluxes. The liquid refrigerant at high pressure expands through orifices, generating a spray that impacts a copper heater. The heated surface is enhanced with laser-micromachined micropillars featuring a square cross-section to improve the thermal conductance of the boiling liquid film. Qualitative evaluations of the enhanced surfaces using interferometry analyses determined the heat transfer surface area and assessed the effectiveness of the fabrication technique. The experiments involved using R-134a, a two-orifice expansion device, and enhanced surfaces with pillar edge sizes ranging from 200 to 600μm. This analysis encompasses the cooling system’s thermodynamic performance, including compressor power and coefficient of performance, as well as steady-state heat transfer parameters such as convection coefficient and critical heat flux. The system achieved a cooling capacity of 230 W (35.9 W/cm2), with the heater surface temperature staying below 22.9 °C and the highest average heat transfer coefficient reaching as high as 55 kW/(m2-K). This represents a 129% increase in thermal conductance compared to mirror polished surfaces, leading to a significant reduction in the temperature of the heated surface. Additionally, the area-corrected heat transfer coefficient is computed to verify the thermal resistance reduction unrelated to the surface area enhancement, and a 60% reduction is found. Furthermore, although this heat transfer enhancement shows minor to no influence on the thermodynamic performance of the refrigeration system, the heater cooling efficiency, defined as the ratio of the enthalpy rise delivered by the heat source to its ideal maximum, increased by 13%. The findings are supported by high-speed video sequences illustrating the boiling heat transfer features.

Persistent Voltage Control of a Wind Turbine-Driven Isolated Multiphase Induction Machine

The growing concern about the energy crisis and environmental protection has caused a growing interest in wind power generation systems. Researchers and engineers urgently need to create new multiphase induction machines for the production of wind energy, since they are essential parts of wind turbines. This study offers control and stability analysis of a multiphase induction machine based on the entropy stability requirements for its linearized model. The generated model was used to assess the on-load properties of the multiphase induction machine and calculate its steady-state parameters under each operating circumstance. According to the analysis, the eigenvalues depend on the machine parameters, with the excitation capacitance and speed variation being the most important. Stabilization of the multiphase induction machine is the main focus of the singular values, which vary according to its variables. The simulated results include an examination of a multiphase induction machine steady state for voltage build-up at various types of load.

Nuclear data effect on BWR stability parameter uncertainty at stable core conditions

The objective of this study is to quantify the influence of nuclear data uncertainties on both steady-state and dynamic core parameters in BWRs, with a specific focus on the uncertainty quantification of stability parameters such as the decay ratio and resonance frequency at stable core conditions. This investigation is carried out within the framework of the OECD/NEA benchmark on the Oskarshamn-2 stability event that occurred in February 1999. The nuclear data uncertainties are propagated, using the in-house SHARK-X platform, through the 2-D lattice calculations using CASMO5 and followed by downstream static and dynamic calculations using and SIMULATE3 and SIMULATE-3 K, respectively. For steady-state, the uncertainty is estimated in terms of k-eff, radial and axial power peaking factors, void fraction, and average fuel temperature, while for the transient, the estimated uncertainties are obtained, for the first time, for the decay ratio and resonance frequency. The results indicate that nuclear data uncertainties have a non-negligible impact on most of the analyzed parameters. More specifically, the uncertainty in k-eff, radial and axial power peaking factors, nodal void fraction peak, and nodal fuel temperature peak for steady-state could reach about 0.5 %, 0.4 %, 2.8 %, 0.1 %, and 1.5 %, respectively, For transient, the uncertainty due to nuclear data for the two stability parameters could reach about 9 % and 2 % for the decay ratio and resonance frequency, respectively.

Parameter Robustness Enhanced Deadbeat Control for DFIG with ESO-Based Disturbance Estimation

Doubly fed induction generators (DFIGs) are widely applied in wind energy conversion systems, where the harsh service environment and long-lasting operation can bring about motor parameter deviations, deteriorating the system performance. In this paper, an extended state observer (ESO)-based deadbeat control strategy that enhances the system parameter robustness is proposed. Firstly, the effects of motor parameter inaccuracy are analyzed to reflect the control errors and degradation of the system performance. Secondly, a lumped disturbance represented by an additional state extended from the system mathematical model is derived with the parameter inaccuracy taken into consideration. Finally, the parameter robustness enhanced deadbeat control method with the ESO-based disturbance estimation is developed to realize accurate prediction and control, even when the inductance of DFIG deviates under various operation conditions. To verify the effectiveness of the proposed method, simulations are carried out in MATLAB/Simulink for a 1.5 MW DFIG with a 30% stator and rotor inductance deviation. Compared to the conventional control method, smooth and fast dynamic performance is maintained, and the current ripple for the proposed control strategy can be reduced by approximately 40%, where the steady-state tracking performance and parameter robustness of the system are significantly enhanced.

Numerical analysis of finite bearing operating under non-Newtonian lubricant and flow turbulence effect

The purpose of this work is to evaluate the combined influence of turbulence and shear-thinning/shear-thickening lubricant on the steady-state characteristics of hydrodynamic journal bearings. The modified Navier–Stokes equation for linear turbulence and non-Newtonian (shear-thinning as well as shear-thickening aspect) lubricants are solved using a finite element method to acquire load capacity, attitude angle, friction coefficient variable, total oil flow, and temperature rise variable for distinct combined values of the flow behavior index and Reynolds number. This work utilizes the Navier–Stokes equation with Ng–Pan's linear turbulence and shear-thinning/shear-thickening lubricant models, which is very helpful in predicting the performance characteristics of hydrodynamic bearings under harsh industrial operating conditions. The results show that the combined presence of non-Newtonian lubricant and turbulence in the flow significantly affects the steady-state performance parameters of such type of bearing compared to existence of individual presence of turbulence and non-Newtonian lubricant in the clearance space. This work helped to provide better insight into the operation of journal bearings in a severe environment owing to the high speed and changes in the nature of lubricant.

Determinants of splenic preservation among patients with sickle cell disease in North-Eastern Nigeria.

In patients with sickle cell disease (SCD), the spleen commonly enlarges during early childhood, but undergoes reduction in size and fibrosis from repeated episodes of vaso-occlusion and infarction. The rate of progression of this process varies markedly among these patients. The aim of current study was to explore clinical and laboratory factors associated with the preservation of the spleen among these patients. Two hundred four patients with SCD (103 females; age 1-45 years) underwent abdominal ultrasonography at the University of Maiduguri Teaching Hospital, Nigeria between October 2020 and November 2021 to assess for splenic visualisation and echotexture. Steady-state clinical parameters and blood samples for full blood count, serum chemistry, high-performance liquid chromatography and malaria parasitemia were obtained from all the patients. The spleen was visualised in 107 (52.4%; 95% confidence interval [CI], 46%-59%) patients with SCD on ultrasonography. While the spleen was visualised in all children less than 5 years of age, it was visualised in only 23.5% of those aged 15 years and older. Visualisation of the spleen was significantly associated with low mean corpuscular haemoglobin concentration and high haemoglobin F (HbF) in those younger than 10 years. The odds of visualisation of the spleen on ultrasonography increased by a factor of 1.17% for every 1% increase in HbF level. Only 32 (15%) patients were on regular hydroxyurea therapy. The HbF level was significantly higher among patients on hydroxyurea (median 12.7 vs. 7.4; p < 0.0001). In patients with SCD, failure to visualise the spleen was not found in children less than 5 years old. Patients with visualised spleens had a higher level of HbF than those with non-visualised spleens. HbF was significantly associated with visualisation of the spleen before 10 years of age. Since early administration of hydroxyurea will increase HbF level, we expect that it would help to preserve the spleen.

Energy optimization and neural-based dynamic analysis of integrated multiple stage evaporator

Abstract Minimizing energy consumption is often a grave challenge in many industrial energy-intensive process units such as Multiple Stage Evaporator (MSE). Integration of Energy Reduction Schemes (ERSs) is a common technique to resume a countable amount of energy. Hence, the present work proposes a hybrid (h-) ERSs integrated MSE placed in the paper industry, used to increase the solid content of the black liquor. The h-ERSs Integrated MSE comprises several ERSs such as Thermo-Vapor Compressor, Steam-, Feed-split, and Feed Preheater to improve the energy efficiency significantly, and its energy performance is compared with base (b-) MSE. For this purpose, nonlinear mathematical models have been developed and transformed into a constrained optimization problem to search for the optimum energy efficiency obtained as Steam Economy (SE). A state-of-art metaheuristic approach, Equilibrium Optimizer (EO), along with some well-acquainted solution approaches (Interior Point OPTimizer, Interior Point Method, and Particle Swarm Optimization) has been simulated in different platforms to estimate the maximum SE to check their competitiveness for this industrial optimization problem. It is observed that EO outperformed all the algorithms with a 66 % higher SE for h-MSE than b-MSE. Eventually, the steady state parameters are applied as the initial conditions to analyze the nonlinear enthalpy dynamics of the b-and h-MSE. A neural base solution has been adopted to rigorously study the open-loop process dynamics that meet the desired product quality.

Deformation and breakup behaviors of a Giesekus viscoelastic droplet in Newtonian shear flow

The deformation and breakup of a Giesekus viscoelastic droplet suspended in a Newtonian matrix under simple shear flow is investigated through a lattice Boltzmann method, which uses the color-gradient model for immiscible two-phase flows while coupling a lattice advection-diffusion scheme for the Giesekus constitutive equation. The influence of the Deborah number (De) and shear-thinning mobility parameter (α) of the droplet is first explored for relatively low capillary numbers (Ca). The transient overshoot is observed before the deformation reaches the steady state, and the overshoot generally increases with De but decreases with α. With the increase of De, the steady-state deformation parameter first decreases and then increases, which is attributed to two opposite effects on the elastic force, namely the promoting effect from the increased polymer extension and the inhibiting effect caused by the deviation of the location where the maximum elastic force occurs from the droplet tips. The droplet inclination angle varies little with α but increases with De, where the latter can be explained as an increased vertical component of viscous and elastic forces in the tip regions. Upon increasing α, the steady-state deformation parameter becomes higher due to the reduced elastic force at the droplet tips. In addition, the phase diagrams of Ca-De and Ca-α are presented in which the critical capillary number Cacr characterizing the droplet breakup can be identified. It is found that Cacr varies non-monotonically with De, while Cacr is not very sensitive to α.

Understanding the mode of action of AgroGain®, a biostimulant derived from the red seaweed Kappaphycus alvarezii in the stimulation of cotyledon expansion and growth of Cucumis sativa (cucumber).

Seaweed-based biostimulants are sustainable agriculture inputs that are known to have a multitude of beneficial effects on plant growth and productivity. This study demonstrates that Agrogain® (Product code: LBS6), a Kappaphycus alvarezii-derived biostimulant induced the expansion of cucumber cotyledons. Seven days treatment of LBS6-supplementation showed a 29.2% increase in area of expanded cotyledons, as compared to the control. LBS6-treated cotyledons also showed higher amylase activity, suggesting starch to sucrose conversion was used efficiently as an energy source during expansion. To understand the mechanisms of LBS6-induced expansion, real time gene expression analysis was carried out. This revealed that LBS6-treated cotyledons differentially modulated the expression of genes involved in cell division, cell number, cell expansion and cell size. LBS6 treatment also differentially regulated the expression of those genes involved in auxin and cytokinin metabolism. Further, foliar application of LBS6 on cucumber plants being grown under hydroponic conditions showed improved plant growth as compared to the control. The total leaf area of LBS6-sprayed plants increased by 19.1%, as compared to control. LBS6-sprayed plants efficiently regulated photosynthetic quenching by reducing loss via non-photochemical and non-regulatory quenching. LBS6 applications also modulated changes in the steady-state photosynthetic parameters of the cucumber leaves. It was demonstrated that LBS6 treatment modulated the electron and proton transport related pathways which help plants to efficiently utilize the photosynthetic radiation for optimal growth. These results provide clear evidence that bioactive compounds present in LBS6 improved the growth of cucumber plants by regulating the physiological as well as developmental pathways.

The Effects of Surfactant and Metal Ions on the Stability and Rheological Properties of Nanoemulsions Loaded with Gardenia Yellow Pigment

The present work reports the preparation of gardenia yellow pigment containing paraffin oil nanoemulsions stabilized by Span80 and Tween80. The preparation of the required nanoemulsions was optimized by testing different conditions, such as varying the hydrophilic–lipophilic balance (HLB), the emulsifier concentration (EC), the oil–water ratio (OWR), and the temperature (T), as determined by the average droplet diameter (ADD) and polydispersity index (PDI). Our results indicated that a minimum ADD of 65.9 nm and PDI of 0.116 were obtained at an optimum HLB value of 6.0, EC of 10% (w/w), OWR of 2:1, and T of 40 °C. Both the steady-state and dynamic rheological parameters were further investigated, revealing that the emulsions exhibited pseudoplastic behaviors. The long-term stabilities of the nanoemulsions after the addition of inorganic salts were monitored by observing their visual appearances. It was found that the emulsions containing pure water or 0.1 M CaCl2 and AlCl3 became slightly separated, while the emulsions containing 0.1 M KCl and NaCl showed no separation after 30 days of storage at room T. This difference among different salts could be related to the number of valence electrons of their cations. The spatial electrostatic effects of the monovalent cationic (KCl and NaCl) and the nonionic surfactants were greater than the delamination/sedimentation forces of the system, which was better than the salt based on the cations with valences greater than one (CaCl2 and AlCl3). In conclusion, the present work illustrated the formation, rheological properties, and stability of water containing gardenia yellow pigment in paraffin oil nanoemulsions, which can be of great significance for the application of gardenia-yellow-pigment-based formulations.

Pattern-electroretinogram in the differential diagnosis of ocular hypertension and primary open-angle glaucoma

PURPOSE. To evaluate the clinical utility of pattern electroretinography (PERG) in the differential diagnosis of ocular hypertension and newly diagnosed primary open-angle glaucoma (POAG) of the initial stage.METHODS. This prospective non-randomized cohort study included patients over the age of 35 years with newly diagnosed ocular hypertension and initial stage POAG in at least one eye. All patients underwent a standard ophthalmological examination, as well as a complex of additional methods used to diagnose POAG: pachymetry, examination of the biomechanical properties of the cornea (Ocular Response Analyzer, Reichert), standard automated perimetry (SAP) (Octopus 900, Haag-Streit Diagnostics), optical coherence tomography (OCT) of the optic nerve head (ONH) and macular area (OCT Triton Plus 3000, Topcon) and PERG (Diopsys Nova, Diopsys, Inc.). Data from both eyes of all included patients were analyzed (12 eyes in the ocular hypertension group and 26 eyes in the POAG group). Statistics was calculated using the StatPlus:mac Software package (StatPlus Inc., Taiwan).RESULTS. During this study we recorded statistically significant differences in steady-state PERG parameters according to the PERG-24 protocol (magnitude, magnitude D — taking into account the magnitude and variability of the response phase throughout the test — and their reverse ratio, determined at pattern contrasts of 100% and 85%) between the groups of patients with newly diagnosed ocular hypertension and newly diagnosed initial stage POAG with a comparable level of intraocular pressure, corneal thickness, biomechanical properties and comparable perimetric indices, as well as the average thickness of the retinal nerve fiber layer and the ganglion cell complex according to OCT data. At the same time, all PERG parameters in the ocular hypertension group were within the normal range, while individual PERG parameters in the POAG group had deviations from the normal.CONCLUSION. Steady-state PERG may be an additional objective method for early detection of disorders in the functioning of retinal ganglion cells (RGCs), which allows differential diagnosis of ocular hypertension without damage of RGCs and initial stage POAG. In addition, dynamic examination with steady-state PERG of individuals with ocular hypertension may allow early detection of the onset of retinal ganglion cells death, i.e. the development of POAG, than with SAP and OCT.

Experimental verification and analysis of the beam loading effect based on precise bunch-by-bunch 3D position measurement

The beam loading effect is one of the main bottlenecks in further improving the performance of synchrotron radiation light sources. Although theoretical analysis and numerical simulation of the beam loading effect have been very well performed, the corresponding diagnostic tools were rather poor, and in most cases, only streak cameras were used to observe the synchronous phase distribution and the intensity distribution in bunch trains. SSRF developed a precise bunch-by-bunch 3D beam position measurement system. This system allows precise measurement and recording of both transient state data and steady-state beam parameters (filling pattern, synchronous phase). Therefore, experimental verification and analysis of the beam loading effect can be more comprehensive and accurate. In this paper, the measurement results of the synchronous phase, synchrotron frequency and synchrotron damping time with and without a third harmonic cavity are introduced and discussed.

Abstract P4-01-21: Phase 2 Study of the CDK4/6 Inhibitor FCN-437c in Combination With Fulvestrant or Letrozole and Goserelin in Patients With HR+, HER2– Advanced Breast Cancer

Abstract Background: FCN-437c is a second-generation CDK4/6 inhibitor. Phase 1b clinical results indicated improved antitumor activity in patients (pts) with HR+, HER2– advanced breast cancer (ABC), treated with FCN-437c + letrozole. Methods: This Phase 2, multicenter, open-label clinical study evaluated the antitumor activity, pharmacokinetics (PK), and safety of FCN-437c + fulvestrant in post-menopausal pts (Cohort 1, treatment-naïve or 2L), FCN-437c + letrozole + goserelin in pre-menopausal pts (Cohort 2, treatment-naïve). Pts received FCN-437c (200 mg QD) in a 21-day-on and 7-day-off schedule either in combination with fulvestrant (500 mg D1) or letrozole (2.5 mg QD) + goserelin (3.6 mg once per cycle) in 28-day cycles. The primary endpoint was overall response rate (ORR) and secondary endpoints were progression-free survival (PFS), overall survival (OS), PK, and safety. Results: At study cutoff (Feb 7, 2022), 36 pts were enrolled in Cohort 1 and 31 pts were in Cohort 2; 42 (62.7%) pts had visceral metastases and 9 (13.4%) pts had bone-only metastases. In Cohort 1, 18 pts were treatment-naïve, 15 pts had received 1L treatment, and 3 pts had received ≥2L treatment. In Cohort 2, 25 pts were treatment-naïve and 6 pts had received 1L treatment. Overall, 27 pts in the per-protocol set achieved partial response (PR), resulting in an ORR of 40.9% (95% CI, 29.0-53.7). Median follow-up was 12.8 months, and median PFS (mPFS), OS, and DOR were not reached. However, at 12 months, the PFS rate was 67.7% (95% CI, 53.2-78.6) and the OS rate was 95.9% (95% CI, 84.5-99.0); the 6-month DOR rate was 96.0% (95% CI, 74.8-99.4). In Cohort 1 (n=35), 11 pts achieved PR: the ORR was 31.4% (16.9-49.3%) and mPFS was 12.9 months (95% CI, 9.2-NR); the 6-month DOR rate was 100%. In Cohort 2 (n=31), 16 pts achieved PR: the ORR was 51.6% (95% CI, 33.1-69.9%). mPFS, OS, and DOR were not reached; the 6-month DOR rate was 92.9% (95% CI, 59.08-98.96) (Table). Treatment-emergent adverse events (TEAEs) were observed in all pts. Majority of AE were G1 or 2 except for hematological TEAE. 58 (86.6%) pts reported grade ≥3 TEAEs, mainly neutropenia (74.6%), leukopenia (49.3%), hypertriglyceridemia (6.0%), lymphocyte count decrease (4.5%), and γ-glutamyltransferase increase (3.0%): most were reversed through dose interruption and symptomatic therapy. Steady-state PK parameters were analyzed after 15-21 days of QD administration: Cohort 1: median Tmax was 3 h, geomean T1/2 was 44.6 h, geomean Cmax was 1650.7 ng/mL, and geomean AUC0-24h was 29,148.08 h*ng/mL; the geomean accumulation ratios of AUC0-24h and RCmax were 2.18 and 1.74, respectively, compared with first dose. Cohort 2: median Tmax was 4 h, geomean T1/2 was 35.7 h, geomean Cmax was 1314.34 ng/mL, and geomean AUC0-24h was 22,889.96 h*ng/mL; the geomean accumulation ratios of AUC0-24h and RCmax were 1.95 and 1.63, respectively, compared with first dose. Conclusion: FCN-437c in combination with fulvestrant or letrozole + goserelin demonstrates antitumor activity and safety and is well tolerated in pts with HR+, HER2– ABC. This combination therapy will be further investigated in 2 ongoing Phase 3 trials (NCT05438810 and NCT05439499). Clinical trial number: NCT05004142. Research Sponsor: Avanc Pharmaceutical Co., Ltd Table. Clinical outcomes for patients in the per-protocol set. Citation Format: JiaJie Shi, Wei Li, Zhongsheng Tong, Aimin Zang, Xiaohua Zeng, Shui Wang, Tao Huang, Ying Wang, Yanqiu Song, Lihua Kang, Zheng Lv, Yehui Shi, Hua Yang, Jing Wu, Yongmei Yin, Yan Liang, Jie Tan, Jie Ming, Yaping Yang, Simin Luo, Xiujuan Gui, Ai-Min Hui, Zhuli Wu, Ling Tian, Yuchen Yang, Lei Diao, Wenjing Zhang, Yongjiao Zhang, Yunjiang Liu. Phase 2 Study of the CDK4/6 Inhibitor FCN-437c in Combination With Fulvestrant or Letrozole and Goserelin in Patients With HR+, HER2– Advanced Breast Cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-01-21.

An Improved Setting-Free Scheme for Fast and Reliable Detection of Complete and Partial Loss-of-Excitation

In this article, an improved setting-free loss-of-excitation (LOE) protection is developed for fast and reliable classification of various events. In the proposed scheme, the internal voltage and reactive power of the synchronous generator (SG) have been exploited to fulfill the condition of not needing the threshold amount because they are directly dependent on the rotor field and continuously reduced during the LOE, leading to having a negative polarity of variation. However, due to slow dynamic variation during the LOE condition, they are multiplied to accelerate and highlight the reduction changes, giving rise to increasing the detection speed. Meanwhile, owing to the considerable difference between the value of internal voltage and reactive power and to highlight the effect of multiplication function, an adaptive gain on the basis of steady-state parameters of SG is suggested. Furthermore, given that the negative polarity of the multiplied parameters can be affected during the hybrid events, the limited integral function is implemented to eliminate the happened swings, resulting in keeping the negative polarity and thus clustering the hybrid events reliably. The performed simulations on the IEEE 9-bus and 39-bus test systems prove that the provided setting-free protection can detect all types of the events reliably and quickly than other schemes.

Comparative analysis on the performance envelope of a three-pad and four-pad active journal bearing

Controllable fluid film bearings with the ability to actively modify the operational conditions of rotor bearing systems possess high demand in the field of rotating machinery. Controllable or active bearing geometries can effectively enhance the performance envelope and life of machine support systems. Alternate forms of an active bearing pad geometry with unique adjustability features having the ability to modify the rotor bearing performance are presented in this study. The adjustability mechanism incorporated in the active pad geometry allows the multiple-bearing pads to translate radially and undergo tilted motions on a real-time basis. These pad adjustments are simulated by incorporating the radial and tilt adjustable functions into the developed theoretical model. In this study, a major focus is on a three-pad active bearing geometry and will further compare its steady state and dynamic performance behavior with a four-pad active bearing model. Effect of varying pad positions, pad angles and number of pads on the steady state and dynamic characteristics are analyzed in this study. For various combinations of operating parameters, pads adjusted to negative radial and negative tilt position were found to provide a notable improvement in the steady state and dynamic performance parameters. Identifying the optimal pad adjustments will further help to develop an active bearing with a feedback control mechanism operated on a real-time basis.

A Single- and Multiple-Dose Pharmacokinetic Study of Oral Perampanel in Healthy Chinese Subjects.

Perampanel is a once-daily oral anti-seizure medication indicated for focal-onset seizures and generalized tonic-clonic seizures. This study investigated the single- and multiple-dose pharmacokinetics of perampanel in healthy Chinese adults. Study 052 (NCT03424564) was a phase I, single-center, open-label, parallel-group study. In the single-dose part of the study, subjects received a single oral dose of perampanel 2, 4, or 8 mg. In the multiple-dose part, subjects received once-daily oral perampanel 2 mg on Days 1-7 and 4 mg on Days 8-21. Pharmacokinetic parameters were determined from perampanel plasma concentrations using non-compartmental analysis. Dose proportionality after single doses of perampanel was assessed. Safety and tolerability were evaluated. In the single-dose part (N=30), median time to reach maximum concentration (tmax) was 0.75-1.0h, mean terminal elimination phase half-life (t½) was 85.6-122h, mean maximum observed concentration (Cmax) was 77.9-276 ng/mL, and mean area under the concentration-time curve from time zero to time of the last quantifiable concentration (AUC(0-t)) was 4070-15100 ng·h/mL. Single-dose pharmacokinetics were linear for perampanel 2-8 mg. In the multiple-dose part (N=12), Day 21 steady-state (4 mg/day) parameters were median time at which the highest drug concentration occurs at steady state (tss,max), 1.25h; mean t½, 109h; mean maximum observed concentration at steady state (Css,max), 453ng/mL; and mean area under the concentration-time curve over the dosing interval on multiple dosing (AUC(0- τ)), 7540 ng·h/mL. For single- and multiple-dose perampanel, the most common treatment-emergent adverse events were dizziness and somnolence. Single- and multiple-dose pharmacokinetics of perampanel in healthy Chinese adults revealed rapid perampanel absorption, slow elimination, and a linear relationship with single perampanel doses of 2-8 mg. Findings were consistent with previous studies of perampanel pharmacokinetics in other ethnic/racial populations of healthy subjects. Single and multiple doses of perampanel were generally safe and well tolerated. NCT03424564; registered February 2018.

Gating defects in K1126I, a putative hypokalemic periodic paralysis mutation in hNav1.4.

We investigated the impact of mutation K1126I reported to be associated with hypokalemic periodic paralysis, but not yet characterized. The location of this mutation is the extracellular positive charge in domain III S4, and characterization of artificial mutations at this locus suggest it is outside the electric field. We used cut-open oocyte electrophysiology to characterize the steady-state and kinetic gating parameters in wild type hNaV1.4, K1126I in both the native background and with incorporation of the 1303IFM/QQQ mutation to isolate activation from fast inactivation. K1126I produced an 11 mV hyperpolarizing (left-)shift in the midpoint of the steady-state fast inactivation curve, and decreased slope. Activation midpoint was left-shifted by 4 mV by K1126I with decreased slope. Recovery from fast inactivation was slowed and entry from closed states was accelerated by K1126I, with open-state fast inactivation and deactivation not significantly altered. Simulated action potentials for which steady-state fast inactivation and activation parameters were incorporated showed a 10 mV attenuation of the skeletal muscle fiber action potential. We used the IFM/QQQ background to compare slow inactivation in wild type and K1126I channels. The midpoint of the steady-state slow inactivation was hyperpolarized by 8 mV in K1126I/QQQ compared to hNaV1.4 / QQQ, with onset unaffected and recovery accelerated. This work was supported by an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under Grant #P20GM103408.

Calculation of Main Circuit Steady-State Parameters for Capacitor Commutated Converter System

The calculation of the main circuit parameters is the basic part of the engineering design for high voltage direct current (HVDC) transmission systems. Compared to the conventional line commutated converter (LCC), the application of the capacitor commutated converter (CCC) can reduce the probability of commutation failures and the shunt capacitor reactive compensation. This paper proposes a calculation method of main circuit parameters for the CCC-based HVDC system. Firstly, the topology of a CCC-HVDC transmission system is described. Secondly, based on the steady-state mathematical model of the CCC, the paper proposes the calculation method of the commutation capacitor to satisfy the system requirements, and the calculation formulas of the main circuit parameters are also given. Then the calculation procedure of the main circuit steady-state parameters is described in detail considering system parameters, control modes, calculation tolerances and operating conditions. Finally, a two-terminal ±500 kV/3000 MW LCC-CCC HVDC transmission system is presented to verify the validity of the main circuit parameter calculation method. The proposed method has great significance for the AC filter design in practical engineering application.