Maximum Relative Power Research Articles

Neutronic and thermal–hydraulic coupling of FCM and helium annular fuel as accident-tolerant fuel

The study aims to explore two types of Accident Tolerant Fuel (ATF) (helium annular fuel and Fully Ceramic Microencapsulated (FCM) fuel), both with Silicon Carbide (SiC) used as clad material and as a matrix material for TRISO (TRi-structural ISOtropic particle fuel) particles in FCM fuel. The safety characteristics (such as maximum fuel temperatures) were evaluated and compared against reference UO2-Zr for a Pressurised Water Reactor (PWR) with neutronic and thermal–hydraulic coupling during normal operation for fresh fuel. The results show that both annular and FCM fuels exhibit reduced maximum temperatures compared to the reference fuel, with a reduction of 479 K (25.3 %) for helium annular fuel and 798 K (42.2 %) in the FCM fuel. The annular fuel improved the burnup by 12.4 MWd/kgU (24.2 %) without the cycle length being affected significantly (−5.6 %). The FCM fuel significantly reduced in the cycle length by 44.1 % while the burnup was more than double the reference providing a 163.5 % increased burnup in comparison to the reference fuel assembly. Assembly pin power peaking factors showed no dramatic deviation from the reference and the axial power distribution of ATFs is more symmetrical than that of the reference fuels. In terms of coupling the pin models converged after eight iterations on average with maximum relative power errors per radial node below 2 %.

Dynamic Muscle Function Parameters in Indian Children and Adolescents with Type 1 Diabetes Mellitus: A Case-Control Study.

Recent evidence reveals that type 1 diabetes mellitus (T1DM) impairs muscle function (MF) in adolescents. However, despite its importance in physical well-being, data on dynamic MF in Indian children and adolescents (C and Y) with T1DM are scarce. We assessed MF using Jumping Mechanography (JM, a measurement method for motion analysis and assessment of muscle power and force). (1) To assess dynamic MF by JM in C and Y with T1DM as compared to healthy controls (2) To determine predictors of MF in children with T1DM. A cross-sectional observational study on 266 children (133 - T1DM duration >1 year with no known comorbidities + 133 age and gender-matched healthy controls) aged 6-19 years. Anthropometry, body composition, and MF (maximum relative power Pmax/mass, maximum relative force Fmax/BW by JM) were recorded. The lean mass index (LMI) was calculated as lean mass (kg)/height (m2). HbA1c was assessed in T1DM. Independent sample t-test and linear regression were performed. MF parameters (Pmax/mass 33.5 ± 7.2 vs 38.0 ± 8.6 W/kg and Fmax/BW 10.5 ± 2.9 vs 11.4 ± 4.1 N/kg, P < 0.05) were significantly lower in T1DM group vs controls. Positive association of body mass index and LMI with both MF parameters and negative association of insulin requirement and HbA1c with Fmax was observed in T1DM. Predictors of MF identified were MMI (Pmax/mass:b = 1.6,95%CI = 0.6-2.6; Fmax/BW:b =2.0,95%CI = 1.6-2.4) and HbA1c (Pmax/mass:b = -2.1,95%CI = -4.5--0.5; Fmax/BW:b = -1.1,95%CI = -2.0--0.2) (P < 0.05). C and Y with T1DM exhibits compromised muscle function. Poor glycaemic control increases the risk of having decreased MF, irrespective of diabetes duration and may contribute to sarcopenia in adulthood.

Multi-physics coupling simulation of small mobile nuclear reactor with finite element-based models

This paper describes the multi-physics coupling simulation of a small transportable nuclear reactor, SIMONS, using the neutronics/thermo-mechanics coupling three-dimensional high-fidelity code platform FEMAS (FEM-based Multiphysics Analysis Software for Nuclear Reactor). FEMAS builds multi-physics field models utilizing the open-source finite element codes deal.II and FEniCS. Using coupling simulations of neutronics, thermal-conduction, and thermo-mechanics, the SIMONS micro mobile reactor is examined. For the generation of cross-sections libraries, the open-source Monte Carlo code OpenMC is utilized, and the (n,xn) correction and SPH method is developed to maintain neutron equilibrium and eliminate homogenization errors. The approaches yield neutronic solutions that are in good agreement with the reference solutions, as the keff error decreases from 5066 pcm to 7.2 pcm and the maximum relative power error decreases from 5.2% to 0.3%. With a thermal power of 240 kW, the local temperature difference of the entire reactor is 354.68 K, and the deformation rate due to thermal stress is 2.4%, resulting in a reactivity feedback of 4459.6 pcm. At the wall in contact with the outermost fuel rods, where the temperature gradient grows substantially and thermal stress rises, the monolith stress is measured to peak at 9.65 MPa. This research has paved the way for a more thorough multi-physics examination of micro nuclear reactors in the era of high-precision computation.

English

Objective: This study aimed to evaluate the effects of creatine on the body composition and performance of college soccer players. Materials and method: Sixteen amateur soccer players were supplemented with creatine (n=8) or maltodextrin (placebo, n=8) for four weeks, using a loading protocol (20g/day in the first week, followed by 5g/day for the rest of the study period). Anthropometric measurements and three physical tests were performed before and after the intervention. Results: After the protocol, the Cr group showed increased body mass (pre 65.1 ± 8.2; post 66.4 ± 8.4; p=0.002), arm (pre 27.7 ± 4.3; post 28.3 ± 4.3; p=0.01), thigh (pre 49.9 ± 4.3; post 51.3 ± 4.6; p=0.012), and leg (pre 34.6 ± 2.3; post 34.8 ± 2.4; p=0.029) circumferences. For bangsbo repeat vertical jump test (BRVJ), there was an increase in maximum power (pre 2965.4 ± 691.8; post 3102.1 ± 818; p=0.034), maximum relative power (pre 44.5 ± 6.5; post 47.1 ± 6.5; p=0.045) and average power (pre 2757.6 ± 653.2; post 2937.7 ± 739.9; p=0.05) only in the Cr group. For running anaerobic sprint test (RAST), there was a significant improvement in average sprint and total times, and in the average power for both groups; however, only the Cr group showed significant improvement in maximum power (pre 517.93 ± 118.82; post 580.15 ± 119.06; p=0.01) and maximum relative power (pre 7.9 ± 1.2; post 8.5 ± 1.3; p&lt;0.001). For wingate test (WIN), improvements were observed in maximum power (pre 456.4 ± 91.0; post 508 ± 79.7; p=0.003), maximum relative power (pre 7.0 ± 0.9; post 7.6 ± 0.6; p=0.012), average power (pre 354.8 ± 69.5; post 410 ± 71.5; p&lt;0.001) and relative average power (pre 5.4 ± 0.6; post 6.1 ± 0.4; p=0.012) only in the Cr group. Conclusions: This study findings demonstrated that Cr supplementation during four weeks promotes positive anthropometric and anaerobic performance changes in college soccer players, especially in lower limbs, but also in upper limbs. However, a possible body mass gain with its use should be considered, so the viability should be individually analysed.

Sex-specific response to whole-body vibration training: a randomized controlled trial.

A few studies have indicated that males and females respond differently to whole-body vibration (WBV) training. However, the existing insights are still insufficient and they cannot be transferred to sex-specific practice planning. To evaluate the effect of 5-week WBV training on neuromuscular [countermovement jump (CMJ), squat jump (SJ)] and cardiovascular [heart rate and blood pressure] data, taking into account sex-specific effects. This is a comparative experimental study including 96 healthy adults, divided into two groups: a WBV group (25 females and 24 males) and a control group (27 females and 20 males). The participants attended nine to ten training sessions (twice a week for 5 weeks), each lasting approximately 30 min. Both groups performed the same exercise routine on the vibration training device. For the WBV group, the training device was vibrating during the whole training session, including the breaks. For the control group, it was turned off. Maximum jump height (H, cm) and maximum relative power (MRP, kW/kg) were noted during CMJ and SJ performed on a force plate. Resting (sitting) heart rate (bpm) and blood pressure (mmHg) were measured twice, before and after the intervention. For each parameter, Δdata (= before – after) was calculated. Interactive effects of sex (2) vs group (2) vs session (2) were noted only in males and they only concerned ΔSJMPR and ΔCMJH: compared to the control group, the WBV group had better ΔSJMPR (1.39 ± 3.05 vs -2.69 ± 4.49 kW/kg, respectively) and ΔCMJH (0.50 ± 6.14 vs -4.42 ± 5.80 cm, respectively). No sex-specific effect of WBV on neuromuscular (CMJ and SJ) or cardiovascular (heart rate and blood pressure) data was found.

Jumping Joints: The Complex Relationship Between Osteoarthritis and Jumping Mechanography

We investigated the relationship between lower limb osteoarthritis (OA) and muscle strength and power (assessed by jumping mechanography) in UK community-dwelling older adults. We recruited 249 older adults (144 males, 105 females). OA was assessed clinically at the knee according to ACR criteria and radiographically, at the knee and hip, using Kellgren and Lawrence grading. Two-footed jumping tests were performed using a Leonardo Mechanography Ground Reaction Force Platform to assess maximum muscle force, power and Esslinger Fitness Index. Linear regression was used to assess the relationship between OA and jumping outcomes. Results are presented as β (95% confidence interval). The mean age of participants was 75.2 years (SD 2.6). Males had a significantly higher maximum relative power during lift off (mean 25.7 W/kg vs. 19.9 W/kg) and maximum total force during lift off (mean 21.0 N/kg vs. 19.1 N/kg) than females. In adjusted models, we found significant associations in males between clinical knee OA and maximum relative power [− 6.00 (CI − 9.10, − 2.94)] and Esslinger Fitness Index [− 19.3 (− 29.0, − 9.7)]. In females, radiographic knee OA was associated with total maximum power [− 2.0 (− 3.9, − 0.1)] and Esslinger Fitness Index [− 8.2 (− 15.9, − 0.4)]. No significant associations were observed for maximum total force. We observed significant negative associations between maximum relative power and Esslinger Fitness Index and clinical knee OA in males and radiographic knee OA in females. We have used novel methodology to demonstrate relationships between muscle function and OA in older adults.

Overview of the SAS4A Metallic Fuel Models and Extended Analysis of a Postulated Severe Accident in the Prototype Gen-IV Sodium-Cooled Fast Reactor

The SAS4A safety analysis code, originally developed for the analysis of postulated severe accidents in oxide fuel sodium-cooled fast reactors (SFRs), has been significantly extended to allow the mechanistic analysis of severe accidents in metallic fuel SFRs. The SAS4A metallic fuel models simulate the metallic fuel thermomechanical and chemical behavior and track the evolution and relocation of multiple fuel and cladding components during the pretransient irradiation and during the postulated accident, allowing an accurate description of the changes in the local fuel composition. The local fuel composition determines the fuel thermophysical properties, such as freezing and melting temperatures, which in turn affect the fuel relocation behavior and ultimately the core reactivity and power history during the postulated accidents. Models describing the fuel-cladding interaction and eutectic formation, the effects of the in-pin sodium on the in-pin fuel relocation, and the postfailure reentry of the molten fuel and fission gas from the pin plenum have also been added. This paper provides an overview of the SAS4A key metallic fuel models emphasizing the postfailure metallic fuel relocation models included in the LEVITATE-M module of SAS4A. The capabilities of the SAS4A metallic fuel models are illustrated through an extended SAS4A analysis of a postulated unprotected loss-of-flow and transient-overpower accident in the metallic fuel prototype Gen-IV sodium fast reactor. The results show that the maximum relative power reached during the postulated accident is 1.19 P0. The favorable characteristics of the metallic fuel cause a significant decrease in net reactivity and relative power due to prefailure in-pin fuel relocation. Negative net reactivity values persist after cladding failure, and the postfailure fuel relocation events occur at low and decreasing power levels.

Light confinement in a 90° double high mesa slot bend waveguide

In this work, we propose a technique to enhance the confinement of light at 90o sharp bend of a double high mesa slot (DHMS) waveguide based on Silicon on Insulator (SOI). These waveguides deliver high electric field and optical power density in low refractive index Nano-metric slot. The slot is displaced to the inner and outer periphery of the bend and explores the deviation in the relative power. The maximum relative power is attained by shifting the slot towards the outer periphery of the bend. This is only conceivable by choosing the precise slot position where the two evanescent tails of the high index waveguide modes have maximum overlap.

Maximum Wave Energy Conversion by Two Interconnected Floaters

Interconnected floaters could use relative rotations around connection joints to drive a power take-off (PTO) system, such that the ocean wave energy can be converted into a useful energy. In this paper, our attention is on the PTO optimization for the interconnected floaters. A fully linear dynamic system, including the linear hydrodynamics of the interconnected floaters and a linear PTO system, is considered. Under assumptions of linear theory, we present a mathematical model for evaluating the maximum wave energy conversion of two interconnected floaters based on the three-dimensional wave radiation–diffraction theory. The model is validated by comparison of the present results with the published data, and there is a good agreement. The model can be employed to calculate the maximum power absorbed by the interconnected floaters under motion constraints due to the restraints of pump stroke or/and collision problem between the floaters. The influence of wave frequency, PTO system, floater rotary inertia radius, and motion constraints on the power capture capability of the two interconnected floaters is also examined. It can be concluded that enlarging the rotary inertia of each floater by using mass nonuniform distribution can be seen as an alternative way of adding PTO inertia. The maximum relative power capture width of the two interconnected floaters with optimized PTO system under constraints is much smaller than that without any motion constraints for long waves.

A real-time laser feedback control method for the three-wave laser source used in the polarimeter-interferometer diagnostic on Joint-TEXT tokamak

A three-wave laser polarimeter-interferometer, equipped with three independent far-infrared laser sources, has been developed on Joint-TEXT (J-TEXT) tokamak. The diagnostic system is capable of high-resolution temporal and phase measurement of the Faraday angle and line-integrated density. However, for long-term operation (>10 min), the free-running lasers can lead to large drifts of the intermediate frequencies (∼100-∼500 kHz/10 min) and decay of laser power (∼10%-∼20%/10 min), which act to degrade diagnostic performance. In addition, these effects lead to increased maintenance cost and limit measurement applicability to long pulse/steady state experiments. To solve this problem, a real-time feedback control method of the laser source is proposed. By accurately controlling the length of each laser cavity, both the intermediate frequencies and laser power can be simultaneously controlled: the intermediate frequencies are controlled according to the pre-set values, while the laser powers are maintained at an optimal level. Based on this approach, a real-time feedback control system has been developed and applied on J-TEXT polarimeter-interferometer. Long-term (theoretically no time limit) feedback of intermediate frequencies (maximum change less than ±12 kHz) and laser powers (maximum relative power change less than ±7%) has been successfully achieved.

Physical fitness and anthropometric characteristics in professional soccer players of the United Arab Emirates

ObjectiveTo describe the anthropometric and physical fitness profiles of elite soccer players acting in the United Arab Emirates. MethodTwenty seven elite soccer players acting in the United Arab Emirates were underwent to an anthropometric evaluation, an incremental test in treadmill and performed the Running-Based Anaerobic Test (RAST). ResultsBody mass index and body fat percentage of the athletes were 23.1±2.0kg.m−2 11.6±2.1 %, respectively. Indirect maximum oxygen uptake (VO2max) was 62.3±5.1ml.kg−1.min−1, mean velocity at VO2max was 17.6±1.5km.h−1, ventilatory threshold (VT) of 13.8±0.8km.h−1, heart rate at VT of 173.1±8.6b.min−1, which represents of 91.2±2.8 % of maximum heart rate. RAST resulted in a maximum absolute power of 551.9±73.0 W, maximum relative power of 7.8±0.4W.kg−1, mean absolute power of 484.0±57.8W, and mean relative power of 6.8±0.2W.kg−1. ConclusionThe anthropometric profile of soccer players that act in the United Arab Emirates is similar to others around the world. However, regarding the physical fitness, results are still inconclusive, since findings from other studies suggest that the anaerobic power of our sample is alike or lower than other elite players throughout the world. Likewise indirect VO2max, especially given the acknowledged limitations of obtaining indirectly this variable. In addition, making an analysis by playing position, the results of this study are similar to previous research.

Experimental Investigation of the Heat-Engineering Characteristics of TVSA Fuel Assemblies With Mixing Lattices

The results of experimental studies of the heat-engineering characteristics and critical heat transfer in 19-rod, electrically heated, models of the alternative heat assemblies TVSA with mixing lattices with deflectors, which secure in-row passage of the coolant, in the range of VVER-1000 coolant regime parameters are presented. The heat-engineering characteristics of a core with TVSA fuel assemblies with three mixing lattices for advanced VVER are determined. It is shown that mixing lattices combined with improved thermohydraulic characteristics of the corner construction of TVSA make it possible to increase the operational reliability of the fuel, implement an efficient fuel cycle, and additionally increase the reactor power to 110 % with maximum relative power of the fuel elements Krmax = 1.63.

Emergency Control Strategy Based on Multi-agent Theory under Blackout

The multi-agent theory is introduced and applied in the way to strike the control amount of emergency control according to stability margin, based on which an emergency control strategy of the power system is presented. The multi-agent control structure which is put forward in this article has three layers: system agent, areal agent and local agents. System agent sends controlling execution signal to the load-local agent according to the position and the amount of load shedding upload from areal agent; The areal agent judges whether the power system is stable by monitoring and analyzing the maximum relative power angle. In the condition of instability, determines the position of load-shedding, and the optimal amount of load-shedding according to the stability margin based on the corrected transient energy function, upload control amount to system agent; local-generator agent is mainly used for real-time monitoring the power angle of generator sets and uploading it to the areal agency, local-loads agent control load by receiving the control signal from system agent. Simulations on IEEE39 system show that the proposed control strategy improves the system stability.

Anaerobic capacity of upper extremity muscles of male and female swimmers

Anaerobic capacity of upper extremity muscles of male and female swimmers Study aim: To assess the anaerobic capacity of upper extremity muscles of male and female swimmers by applying two exercise tests. Material and methods: Male and female swimmers (n = 9 and 6, respectively), aged 19 - 23 years and having training experience of over 10 years, were subjected to two tests: 30-s Wingate for upper extremities and semitethered swimming test. The following variables were determined: body fat content (from 4 skinfolds), maximum power output, heart rate (HR) and lactate (LA) concentration in blood. Results: Relative power outputs in the Wingate test and swimming force in semi-tethered swimming test (maximum and mean) were significantly (p&lt;0.001) higher in male than in the female swimmers. Maximum LA concentrations were higher in male than in female swimmers, but maximum LA values related to relative power output were in both genders alike. Maximum force produced in the semi-tethered swimming test was strongly (r = 0.765; p&lt;0.001) correlated with maximum relative power output in the Wingate test. Conclusions: Both tests may be interchangeably applied to determine the anaerobic capacity of upper extremity muscles in swimmers.

周囲雑音を用いた無音物体探知における高分解能アレイ信号処理手法の比較

Much attention has been paid to the new idea of detecting objects by using ocean ambient noise affirmatively. This concept is called acoustic daylight imaging. The authors have tried to detect a silent target object using ambient noise by employing a wide-band beam former consisting of an array of receivers. In experimental results obtained in air, we have applied the delay-sum array (DSA) method and the multiple signal classification (MUSIC) method to successfully detect a silent target object in an acoustic noise field generated by a large number of transducers by using a wide-band beam former. In this paper, we applied the minimum variance (MV) method to detect silent targets as one of the promising high resolution technique of the array signal processing method. The relative power levels near the target obtained with MV and MUSIC were compared with those obtained by DSA. Then, the effectiveness of the MV and MUSIC method was evaluated according to the rate of increase and the direction in the maximum relative power levels.

Investigation of underwater acoustic noise for three different areas

The results of underwater acoustic noise measurements at different sites in the Persian Gulf, Karadj Dam lake and at a small lake west of Tehran are investigated on the basis of time series and relative power spectra. Several possible sources such as shipping, wind, surf, industrial activities on shore, thermal agitation etc. are distinguished to determine the most probable origins of the observed noise. The ambient noise of the Persian Gulf is found to be a composite of at least three overlapping components: turbulent-pressure fluctuations, noise due to shipping with a maximum relative power around 50–60 Hz, and that due to wind with a maximum around 800 Hz. Spectrum characteristics of each component and of the composite are shown. The radiated noise of some different classes of ships and boats measured in the Persian Gulf and Karadj Dam lake are also discussed. Additional sources, including those of intermittent and local effects, such as bubbles, rain, snow, flying aircraft, etc., are also investigated in the small lake. Finally the Gaussianity and stationarity of the recorded data are studied through appropriate tests.

Fast activity and oscillatory potential of carp retina in the frequency domain

There are two kinds of fast activity in the ERG: fast retinal potentials (FRP), an irregular series of spiky wavelets and oscillatory potentials (OP), a rhythmic sequence of events. Corneal ERG from nine intact young carps, evoked by extended pulses of diffuse white light under mesopic adaptation, displayed two different groups of wavelets related to ON and OFF, respectively. Stimulation and recording conditions were established to permit separate Fourier analysis of both groups of wavelets. Power distributions of normalized ON spectra showed both a wide dispersion and a high inter-subject variability. All normalized OFF spectra showed, instead, components within a narrow band from 52 to 56 Hz, most of them maximum relative power peaks. It is concluded that FRP originating in highly labile sources dominate ON fast activity, while the predominant OFF fast activity are OP originating in a stable discrete source.