High Power Levels Research Articles

KENESARY KASSYMOV İN PRE-REVOLUTİONARY HİSTORİOGRAPHY

This article considers the directions and features of the study of the national liberation uprising against the colonialism of tsarism, led by Kenesary Kassymov in 1837-1847 in the work of pre-revolutionary authors Kenesary Khan is a personality, his name occupies a special place in the history of not only Kazakhstan, but also Central Asia.He became famous for being a sultan («аксүйек»aristocracy -auth.) belonged to the tyure («төре » representatives of the Genghis Khan family - auth.)was the last khan of the Kazakhs, also a batyr (knight, hero - auth.) and leader of the national liberation uprising.M.I. Venyukov cited the name of Kenesary only as an example to clarify the methods of warfare. L.Meyer provided relatively complete data on the activities of Kenesary Kassymov. N.I. Krasovsky acknowledged that for the Kazakhs, the unity and independence of the people were the main values.According to V. Potto, every year the colonization of the Zhetisu (Semirechye - auth.) is intensified by foreigners from the interior of Russia, mainly in the south of the region. Although M. Terentyev showed Kenesary's high level of power, he likened his warriors to pirates. Zavalishin described the movement ofKenesary Kassymov as an uprising, not just a riot or robbery. It is known that Ch.Ch. Valikhanov called Kenesary the most courageous rebel.А. Kenesarin's note tells about the life and work of the Kenesary, the details of his death. N.A. Sereda recognized Kenesary as a political opponent of the Russian Empire and its long struggle as a war of the Kazakh people for the restoration of independence. In А. Yanushkevich's works, there are conflicting opinions about Kenesary. A. Dobrosmyslov estimated that Kenesary was the last false khan of the Middle Horde.

KENESARY KASSYMOV İN PRE-REVOLUTİONARY HİSTORİOGRAPHY

This article considers the directions and features of the study of the national liberation uprising against the colonialism of tsarism, led by Kenesary Kassymov in 1837-1847 in the work of pre-revolutionary authors Kenesary Khan is a personality, his name occupies a special place in the history of not only Kazakhstan, but also Central Asia.He became famous for being a sultan («аксүйек»aristocracy -auth.) belonged to the tyure («төре » representatives of the Genghis Khan family - auth.)was the last khan of the Kazakhs, also a batyr (knight, hero - auth.) and leader of the national liberation uprising.M.I. Venyukov cited the name of Kenesary only as an example to clarify the methods of warfare. L.Meyer provided relatively complete data on the activities of Kenesary Kassymov. N.I. Krasovsky acknowledged that for the Kazakhs, the unity and independence of the people were the main values.According to V. Potto, every year the colonization of the Zhetisu (Semirechye - auth.) is intensified by foreigners from the interior of Russia, mainly in the south of the region. Although M. Terentyev showed Kenesary's high level of power, he likened his warriors to pirates. Zavalishin described the movement ofKenesary Kassymov as an uprising, not just a riot or robbery. It is known that Ch.Ch. Valikhanov called Kenesary the most courageous rebel.А. Kenesarin's note tells about the life and work of the Kenesary, the details of his death. N.A. Sereda recognized Kenesary as a political opponent of the Russian Empire and its long struggle as a war of the Kazakh people for the restoration of independence. In А. Yanushkevich's works, there are conflicting opinions about Kenesary. A. Dobrosmyslov estimated that Kenesary was the last false khan of the Middle Horde.

Dynamic Grid Voltage-Based Impedance-Reshaped Control for the Stability Enhancement of Grid-Connected DC/AC Converter System under Bidirectional Power Flow

Considering the bidirectional three-phase DC/AC converter, it presents different impedance characteristics on AC side under different power flow directions, resulting in different stability margin. This may cause the system instability at high-power level. This directionally oriented stability difference has not been paid enough attention in the grid-connected converter control. To mitigate the stability variations under bidirectional power flow, a dynamic grid voltage-based impedance reshaping control is proposed in this paper. The proposed method extracts the grid voltage dynamic component, and correspondingly compensates the power output, which is capable of regulating the power output coordinated with voltage dynamics in both power flow directions, neutralizing the stability difference and enhancing the bidirectional power flow stability. Unlike the conventional unidirectional damping optimization control in the current loop, the proposed control method can maintain satisfied stability under bidirectional power flow through the grid side voltage, which can avoid increasing the current loop delay, and thus endow the converter flexible bidirectional power process capability. The effectiveness of the proposed method has been verified by both simulations and experiments.

Pragmatic Approach: A Study of Politeness Strategies in Pakistani Morning Shows

The purpose of this study was to explore the use of different politeness strategies in Pakistani Morning shows and to find out the highly frequently used politeness strategies. It further explored the factors affecting the use of different politeness strategies. The data was collected from two Pakistani morning shows “The Morning Show” and “Ek Nayee Subah with Farah”. Brown and Levinson’s (1987) politeness strategies were explored in the utterances of speakers. The frequency of using these strategies was counted and the factors influencing the speakers to choose these strategies were analysed. The findings revealed that the hosts and guests employed all of the fifteen sub-strategies of positive politeness frequently to maintain close relationship. However, the hosts, as the higher level power participants, also apply bald-on strategy to be authoritative with their assistants and the audience. Negative politeness and its ten sub-strategies were less frequently used by the speakers. Different power ranks also affected the choice of politeness strategies because participants having high power used bald-on record strategy but same power ranks showed the application of negative and positive politeness.

Validation of a numerical model for hot-spot detection on the surface of a rotor pole using a scale model of a hydroelectric generator

To meet the ever-increasing demand for electricity, Hydro-Québec is investigating the viability of running its existing hydroelectric generators at higher power levels than their current operating limits. To assist in this investigation, numerical models capable of simulating the conjugate turbulent air flow and heat transfer phenomena in these generators were formulated and then validated, by using them to predict these phenomena within a scale model of a hydroelectric generator available at Hydro-Québec’s Research Institute and comparing the results to complementary experimental data. Reynolds-averaged governing equations were used, with turbulent stresses and heat fluxes approximated using eddy-viscosity and eddy-diffusivity approaches, in conjunction with the standard k − ɛ and a k − ω shear-stress-transport models, constant turbulent Prandtl number, and specialized treatments of the near-wall regions. Variable- and constant-fluid-property formulations (with coupled and decoupled solutions of the fluid flow and heat transfer) were assessed. The discretization of the complex geometry and the governing equations, and solutions of the discretized equations, were done using commercial codes. These numerical models gave favorable and comparable results, with predictions of global flow quantities (such as windage losses and overall mass flow rates) lying within 4%, and average and maximum temperatures of the pole surface within 5 °C and 3 °C, respectively, of the corresponding experimental data when using the constant-property, coupled, standard k − ɛ model with specialized wall functions. However, the equivalent decoupled model, which was the least computationally intensive, was also adequate for the task at hand. Numerical assessments of two alternate ventilation configurations in the scale model were also undertaken. They showed that increasing the surface area of the spider arms reduced the maximum temperature of the pole by 2.6 °C; and restricting the rotor inlet area reduced the windage losses and the maximum temperature of the pole by 4.7% and 1.5 °C, respectively. • 3D Conjugate heat transfer simulations of a hydroelectric generator scale model. • Validation of flow and temperature distributions by way of experimental measurements. • In contrast with design assumptions, flow across the rotor rim ducts is non-uniform. • Numerical predictions of hot-spots on the scale model’s rotor to within 2.7 °C. • Proposed modifications to the rotor design to reduce rotor pole hot-spot temperatures.

Design of Winner-Takes-All Circuits in Competitive Neural Networks

The Winner-Take-All circuit is an important part of the competition layer in the competitive neural network. Its main function is to compare the size of the output of the nodes after the weighted summation of all input vectors, and select the node with the largest output to output high power level, while other nodes output low level, that is, to find the node with the largest output. According to the characteristics of the Winner-Take-All circuit in the competitive neural network, the simulation of the Winner-Take-All circuit is carried out by the PSPICE simulation software. The physical test results show that, like the simulation diagram of the Winner-Take-All circuit, it conforms to the logic truth table, which further confirms the rationality and correctness of the Winner-Take-All circuit. Hardware realization of Winner-Take-All circuit as an important component of competitive layer in competitive neural networks has important research significance.

Multiphase Induction Motor

Many researchers have studied multiphase Induction motor drives and output of these research shows that output Torque of these motors is superior to that of normal three phase Induction motor. Limitations on the power level of semiconductor devices establish a barrier to the increase of converter ratings. In order to get rid of this limitation, multilevel converters have been developed where switches of reduced rating are used to construct high power level converters. Instead of multilevel converters, multi-phase machines are used: By dividing the handled power between multiple phases, generally more than three, high power levels can be achieved even using limited rated power electronic converters. The aim of this research is to implement novel design and development of six phase induction motor. Also control of the same motor is carried out when fed by two, three phase inverters.

Boost DC-DC Converter with Switched-Capacitor and Four-State Switching Cell

The integration of switched-capacitor voltage multiplier cells in basic converter topologies has been studied to provide voltage gain and voltage stress reduction. However, SC cells do not provide current sharing and additionally they induce high current spikes in the devices, which are limitations of these structures to operate in high power levels. The main contribution of this paper is to overcome this drawback proposing the use of a multistate switching-cell for current sharing in SC-based boost converters, which reduces the current stress in the power devices and increases the power levels of this family of converters. The proposed concept can be generalized for m number of SC cells and n number of switching cells to increase the voltage gain and current levels. Furthermore, it can be applied to other basic structures. The theoretical analysis of the proposed structure was evaluated experimentally in a 3 kW boost-type dc-dc converter, achieving 200 V to 1200 V voltage gain, and reaching 98.4% of maximum efficiency.

The relationship between handgrip strength and performance scores in North American Collegiate Division I women’s artistic gymnasts

Maximal isometric handgrip strength (HGS) is used as an indicator of overall muscular strength and has also been found to be predictive of certain athletic events sporting prowess. Women’s artistic gymnastics requires athletes have high levels of relative muscular strength and power to be successful. This study examined the relationship between HGS and gymnastics performance scores for the 4 events of vault, uneven bars, beam, and floor in female collegiate artistic gymnasts. Twenty-five (n=25) female National Collegiate Athletic Association (NCAA) Division I North American collegiate women’s artistic gymnasts (age: 20.1±1.3 yrs; height: 158.9±5.6 cm; mass: 58.2±5.3 kg) were assessed for a one-time measurement of absolute HGS in kg and relative HGS (HGS/height in m2), as well as their average vault, uneven bars, beam, and floor performance scores across a competitive season. Pearson correlation coefficients (r) were determined between HGS and all performance scores. No significant (p > 0.05) correlations were found between absolute HGS (30.8±4.4 kg) or relative HGS (12.0±1.6 kg/m2) and any 4 gymnastics event’s performance scores (r range: -0.07 – 0.50 or r range: -0.06 – 0.31, respectively). In this female collegiate gymnastics’ population, 56% had an absolute HGS and 80% had a relative HGS, respectively, above the 50th percentile of all similarly aged adult females in the United States. In the current population of female collegiate gymnasts, absolute and relative HGS were not related to any gymnastics events performance scores and adds to the existing literature, supporting no relationships between HGS and sports performances where sports movements require a high degree of technical precision and accuracy. Findings from this investigation can be used by athletes, coaches, and practitioners in the collegiate women’s gymnastics realm to assess if athletes have attained sufficient absolute HGS, and especially relative HGS values, to be successful.

Experimental and statistical study of an in-situ ultrasound (US)-assisted ultrafiltration process: Application to fouling control in skimmed milk filtration

In the present work, in-situ ultrasound was employed as an innovative technique for fouling control and membrane cleaning in ultrafiltration of skimmed milk solution. A response surface methodology (RSM) was used to examine the influence of operational parameters, including US power and frequency, solid concentration, and feed flow rate, on the performance of the US-assisted ultrafiltration process. The experiments were conducted without US irradiation initially, and the results were compared to those obtained through US-assisted filtration. Filtration performance was found to improve at higher levels of power and feed flow rate and at lower levels of US frequency and solid concentration. The total mass of permeate, permeate flux, and mass of particles retained on the membrane were determined for each run. The permeate flux was improved using US by >67 % at the optimum conditions of 100 w, 28 kHz, 0.5 wt%, 1 L/min). A novel synchrotron X-ray high contrast imaging technique available at the Canadian Light Source (CLS) was employed for real-time visualization of US-generated bubbles and its influence on fouling control. It was observed that the number and size of the microbubbles increased as the US power enhanced from 50 W to 100 W. Under the influence of the US frequency, significantly larger bubbles were created at 20 kHz, while microbubbles' size decreased when the frequency changed to 40 kHz. A non-phenomenological mathematical model was also developed to predict US-assisted ultrafiltration performance under the defined factor levels.

Oxygen vacancies in LiB3O5 crystals and their role in nonlinear absorption

LiB3O5 (LBO) crystals are used to generate the second, third, and fourth harmonics of near-infrared solid-state lasers. At high power levels, the material’s performance is adversely affected by nonlinear absorption. We show that as-grown crystals contain oxygen and lithium vacancies. Transient absorption bands are formed when these intrinsic defects serve as traps for “free” electrons and holes created by x rays or by three- and four-photon absorption processes. Trapped electrons introduce a band near 300 nm and trapped holes produce bands in the 500-600 nm region. Electron paramagnetic resonance (EPR) is used to identify and characterize the electrons trapped at oxygen vacancies (the unpaired electron is localized on one neighboring boron). Self-trapped holes and lithium vacancies with the hole trapped on an adjacent oxygen are also observed with EPR. At room temperature, we predict that most of the unwanted defect-related ultraviolet absorption created by a short laser pulse will decay with a half-life of 29 µs.

Thermal Estimation and Thermal Design for Coupling Coils of 6.6 kW Wireless Electric Vehicle Charging System

Wireless electric vehicle charging technology is developing in the direction of high power levels. However, more generated heat brought by higher power will accelerate the system’s aging and can even lead to damage. An excellent thermal design for the magnetic coupler can reduce each part’s maximum temperature, ensuring long-term operation reliability. Therefore, in this article, the magnetic coupler’s thermal estimation and design are studied based on a 6.6 kW wireless electric vehicle charging system. First, the calculation method of internal resistance of a litz coil, core loss, and eddy current loss of a shielding aluminum plate are studied. Considering the influence of thermal fields on material properties, each part’s power loss calculation formula is further modified to improve the accuracy. After that, heat dissipation research is carried out. The heat dissipation measures, such as filling the surface of the shielding aluminum plate with thermal conductive silicone grease, are proposed. Finally, the effectiveness of the heat dissipation measures is verified by simulation and experiments. The experiment shows that the error between the power loss value of each part calculated by simulation and measured by the experiment is less than 15%, and the maximum temperature of the magnetic coupler is controlled below 80 °C.

High-level power estimation techniques in embedded systems hardware: an overview

High-level power estimation techniques in embedded systems hardware: an overview

Formation Mechanism of a Coastal Zone Environment Collaborative Governance Relationship: A Qualitative Comparative Analysis Based on fsQCA.

The coastal zone is an area where terrestrial and marine ecosystems intersect. This region may be subject to outstanding environmental issues, as influenced by many stakeholders. Based on the framework of collaborative governance, the starting conditions for forming a coastal zone environment collaborative governance relationship are proposed as follows: coastal zone environment, balanced level of power and resources, superior-level government participation, and previous cooperation experience. The coastal environmental governance practices of 14 cities along the continental coastal zone of the East China Sea are selected as cases, in order to test the interactions between and influence mechanisms of the starting conditions. As qualitative comparative analysis (QCA), based on set theory and Boolean algebra, is a popular tool to explain complex collaboration situations in small-N cases; and as fuzzy-set qualitative comparative analysis (fsQCA) allows for fine classification of the membership degree (where the condition can be allocated any number between 0 and 1), we use fsQCA to analyze the collaborative governance relationships. The results of the analysis demonstrate that three combination configurations promote the formation of medium–high intensity collaborative governance relationships: high balance level of power and resources × high previous cooperation experience, high pollution of coastal zone environment × high balance level of power and resources × low superior-level government participation, and high pollution of coastal zone environment × high superior-level government participation × high previous cooperation experience. Based on this conclusion, we determine three types of relationship formation modes: wheel-, echo state network-, and umbrella-shaped modes. Notably, under certain conditions, superior-level government participation is not necessary for the formation of a medium–high intensity collaborative governance relationship.

A 1-kW and 100-cm Distance Magnetically Coupled Resonant WPT System Achieving 80% Efficiency

For the magnetically coupled resonant wireless power transfer (MCR WPT) applications with high-power level and medium-range distance, the low coupling coefficient brings severe challenges to the system efficiency and reliability, as the coil loss and the voltage/current stress on compensation components are both considerable; meanwhile, the high operating frequency that contributes to improve the power density will result in high switching loss and related electromagnetic interference. In this article, a parameter design methodology for high-power and medium-range-distance MCR WPT applications was proposed to achieve high system efficiency. The accurate time-domain system model was built to obtain the relationship among voltage/current stresses on the compensation components, zero-voltage-switching (ZVS) conditions of power switches and system parameters. The key parameters, including the switching frequency, the coil self-inductance, and the compensation inductance, are designed to realize wide-range ZVS and reduce voltage/current stresses. Double-layer coil configuration was adopted instead of the traditional single-layer coil to reduce coil losses, and the series compensation capacitors in TX and RX coils were split to achieve current sharing between double-layer coils. Meanwhile, the LCCL-TT compensation network was used to achieve the optimal load and maximize the system efficiency. Finally, a 1-kW MCR WPT prototype within 100-cm transmission distance was implemented in the laboratory for experiments, and the system efficiency under the rated condition is 80.62%.

A Physiological Profile Of Male And Female Division I Collegiate Tennis Players

Tennis requires high levels of reaction time, muscular power, and aerobic capacity. Assessments of these physiological parameters can aid in making decisions on training priorities, adaptations, and overall readiness. PURPOSE: The purpose of this analysis was to evaluate physiological and performance characteristics of male and female tennis players and identify relationships between metrics. METHODS: Collegiate tennis players (male [M]: n = 7, age = 20.7 ± 1.3 y, height = 186 ± 4 cm, body mass = 82.2 ± 4.5 kg; female [F]: n = 10, age = 19.6 ± 1.3 y, height = 166 ± 5 cm, mass = 65.3 ± 9.2 kg) participated in preseason testing to assess body composition, reaction time, muscular power, and aerobic capacity. First, body composition (body fat percentage [%BF], fat-free mass [FFM]) was measured by air-displacement plethysmography (BODPOD), followed by simple (Dynavision D2) and whole-body dynamic (Trazer) reaction time (RT), muscular power via maximal countermovement vertical jump with hands on hips (CMJ), and aerobic capacity (VO2max) via maximal graded exercise testing. Descriptive statistics are presented as mean ± standard deviation, and relationships between metrics were assessed using Pearson’s correlations (r) with an alpha-level of 0.05. RESULTS: Average %BF and FFM were 10.8 ± 4.0% and 73.3 ± 3.6 kg for M and 21.6 ± 6.2% and 51.7 ± 6.7 kg for F. Simple RT was 0.7 ± 0.1 s for both M and F, and dynamic RT was 0.5 ± 0.0 s for M and F. CMJ height was 56.4 ± 6.2 cm for M and 41.9 ± 4.4 cm for F. VO2max was 57.1 ± 5.1 mL/kg/min for M and 47.3 ± 5.8 mL/kg/min for F. %BF was inversely related to both CMJ (r = -0.72; P < 0.01) and VO2max (r = -0.77; P < 0.01). CONCLUSIONS: Overall, this sample was relatively lean, though M met the “Good-Excellent” category while F met the “Fair” category according to ACSM standards. Both measures of RT were consistent across M and F, though M had higher CMJ. VO2max was also higher in M, but both teams were considered “Excellent.” Correlational findings suggest increased BF% may negatively impact both anaerobic and aerobic performance, as athletes with higher BF% had lower CMJ heights and cardiovascular fitness. Future research should assess how these measures, particularly reaction time metrics, relate to on-court tennis performance.

Feasibility of wideband dielectric imaging to guide temperature-controlled atrial fibrillation ablation.

The DiamondTemp (DT) radiofrequency (RF) ablation catheter (Medtronic, Dublin, Ireland) has been introduced for atrial fibrillation (AF) ablation. It features 6 thermocouples at its tip, imbedded in a synthetic diamond material that offers high thermal diffusivity. The technology allows temperature-controlled ablation combining high ablation power levels with a direct temperature feedback consequently resulting in homogeneous atrial lesion formation.1 Recently, a novel wideband dielectric imaging system (KODEX-EPD, EPD Solutions, Philips, Amsterdam, The Netherlands) was introduced to guide catheter ablation of cardiac arrhythmias.

Classifying jobs towards power-aware HPC system operation through long-term log analysis

The efficient utilization of high-performance computing (HPC) system resources under rigorous electric power budget or I/O workload constraints is among the most important goals set by system operators to deal with the demanding requirements of application users. In most cases, the effective utilization of CPU and memory devices, which is tightly linked to electric power consumption, is a counterpart metric of I/O activities in most HPC jobs. Towards higher utilization of HPC systems under strict electric power consumption and I/O activity management constrains, we must be careful to prevent hot-spots from developing in power consumption or I/O operations that could lead to unstable system operations by exceeding electric power supply or I/O subsystem capabilities. One of the feasible solutions is arranging compute node assignment not to have such hot-spots in electric power or I/O operations. To address this issue, we analyzed vast amounts of log data collected from the K computer and found strong positive correlations between CPU and memory device utilization rates and electric power consumption levels. On the one hand, we also observed strong negative correlations and reduced electric power consumption in relation to file I/O activities in a specific compute node-layout, thereby indicating unique characteristics in some I/O-intensive HPC jobs in the node-layout. Our investigation revealed that HPC jobs could be divided into two groups when classified in terms of required electric power — jobs consuming high electric power levels and I/O-intensive jobs with reduced electric power levels. Then, we achieved high levels of accuracy when classifying jobs in terms of electric power levels using RandomForestClassifier among multiple machine learning classification models provided from scikit-learn . The classification can prevent us from hot-spots in electric power consumption in compute node assignment in job scheduling. Thus we demonstrated efficient job classifications towards power-aware system operations in the supercomputer Fugaku, which is the successor to the K computer.

Application Prospects of the Superconducting Dynamic Synchronous Condenser

The new power system based on renewable energy sources may bring the problems of voltage and frequency stability due to the high-level power electronic-based interfaced generation. As a reliable reactive power compensation equipment, dynamic synchronous condensers (DSCs) have the merits of short response time and high overload capacity. They can also improve the system inertia and short-circuit current capacity, and play the role of voltage and frequency stabilizer in the power system. Compared with the conventional DSCs, the superconducting DSCs have higher efficiency, stronger voltage support ability and more excellent reactive compensation performance. In 2018, a research project was launched to explore the feasibility of the superconducting DSC in power grid. The project has achieved significant progress. A hundred-kW prototype was designed and made for technical verification, and the design procedure of the 10 Mvar one is being carried out.

ASSOCIATIONS BETWEEN LOW ENERGY AVAILABILITY, EATING DISORDERS RISK AND BODY DISSATISFACTION IN ADOLESCENT FEMALE ATHLETES

Previous research has suggested that athletes at risk of low energy availability can present with symptoms other than those traditionally expected and highlight the complexity of identifying individuals at risk. It is very important to recognize as early as possible the risk of low energy availability by evaluating the presence of symptoms which include menstrual and gastrointestinal dysfunction, injury history, as well as oral contraceptive use. This is especially so in aesthetic sports which require high levels of strength, power, and endurance as well as artistic skills to perform in different environments. This study aimed to verify possible links between low energy availability, eating disorders risks, and body dissatisfaction in aesthetic sports' adolescent athletes. Seventy-one female athletes (mean ± SD, age: 17.55±3.15 years; height: 169.70 ± 6.27 cm; weight: 58.75 ± 6.42 kg; training 13.79±6.71 hours/week) completed questionnaires: Low Energy Availability Questionnaire (LEAF-Q), Eating Attitudes Test (EAT), and Body Dissatisfaction Scale (BSQ). Results suggested that most of the examined female athletes fall into the normal range of BMI scores with regard to body mass and eating patterns, but there are athletes with very high scores on the questionnaires among them. No significant correlations were reported between low energy availability and other study variables, but EAT-26 and BSQ scores correlated significantly (r=.694, p&lt;.000). Furthermore, BMI correlated with BSQ scores (r=.447, p&lt;.000) and EAT-26 scores (r=.265, p&lt;.050). The study confirmed the relationship between body image concerns and pathological eating attitudes among female aesthetic sport athletes, but not with low energy availability.