Value Of Resistive Load Research Articles

Improving electric power generation of a standalone wave energy converter via optimal electric load control

This paper aims to investigate electric dynamics and improve electric power generation of an isolated wave energy converter that uses a linear permanent magnet generator as the power take-off system, excited by regular or irregular waves. This is of significant concern when considering actual operating conditions of an offshore wave energy converter, where the device will encounter different sea states and its electric load needs to be tuned on a sea-state-to-sea-state basis. To that end, a fully coupled fluid-mechanical-electric-magnetic-electronic mathematical model and an optimization routine are developed. This proposed time-domain wave-to-wire model is used to simulate the hydrodynamic and electric response of a wave energy converter connected to specific electric loads and also used in an optimization routine that searches optimal resistive load value for a wave energy converter under specific sea states. Sample results are presented for a point-absorber type wave energy converter, showing that the electric power generation of a device under irregular waves can be significantly improved.

IMMUNOLOGICAL INDICES OF THE HUMAN IN CONDITIONS OF THE APPLICATION OF INDIVIDUAL MEANS OF PROTECTION OF RESPIRATORY ORGANS

The purpose of the work was to study reactions of the immune system with the use of additional respiratory resistance arising from the use of personal respiratory protection. The inspiratory resistance to respiration of 20, 40 and 60% Pmmax was used. The study involved 26 male and female cases at the average age of 21,22,23 years. Based on the results of the study the short-term (3 minutes) effect of inspiratory resistive loads was shown to have a pronounced effect on the population and subpopulation composition of blood lymphocytes, practically without changing the level of secreted immunoglobulins. Different values of additional resistance to respiration were noted to statistically significantly change the level of biogenic amines: the concentration of epinephrine and norepinephrine with elevating values of resistive loads progressively increased; the serotonin concentration shows the opposite dynamics. The work demonstrates the additional respiratory resistance of 20% Pmmax fail to change the immunological status of the subjects. The resistive respiratory load of 40% Pmmax caused immunosuppressive changes in the population composition of lymphocytes and indices of nonspecific immunological resistance. An additional respiratory resistance of 60% Pmmax induced an immunostimulatory effect in the change in the population composition of lymphocytes and in indices of nonspecific immunological resistance. Based on the data obtained, a suggestion has been made that in designing individual respiratory protection devices it is advisable to limit the value of additional inspiratory resistance to respiration of 20% Pmmax.

Optimal range of loading for operating a fixed-speed wind turbine using a self-excited induction generator

In the present study, a new strategy of analysis was used to determine the optimal interval of a single-phase resistive load to operate a fixed-speed wind turbine. The essence of this optimal range is to enable the generator to have stable voltages and current balances, large power, and an acceptable frequency range, and also mitigate generator overheating. The generator windings and excitation capacitances were prepared according to the C-2C connection scheme with suitable values of excitation capacitances. The admittance matrix of the system was based on positive and negative sequence generator voltages and was calculated by symmetrical components theory. The generator performance was found through optimization of the determinant admittance matrix magnitude. Moreover, balanced position of the generator can be achieved near the maximum load power. Consequently, the best interval of resistive load of the generator (1.5 kW) was found around 2% voltage unbalance factor. The appropriate optimal load was approximately ±6% of the perfect balance resistive load value.

Tongue-Strengthening Exercises in Healthy Older Adults: Does Exercise Load Matter? A Randomized Controlled Trial.

Tongue-strengthening exercises (TSE) are based on the principles of exercise and motor learning, including intensity. Intensity is manipulated by gradually adjusting the resistive load. This randomized controlled trial (RCT) investigates the effect of three different values resistive load during TSE in healthy older adults. Sixty subjects completed 8weeks of TSE while exercising with Iowa Oral Performance Instrument (IOPI). They were randomly distributed to 4 different treatment arms: 3 exercise groups (EG1: n = 15; EG2: n = 16, EG3: n = 16) and 1 control group performing lip-strengthening exercises (CG: n = 13). Values of resistive load for EG1, EG2, and EG3 were 100, 80, and 60% 1RM, respectively. Anterior and posterior maximal isometric pressures (MIPA, MIPP) were measured at baseline, after 4 and 8weeks of training and 4weeks post-training. MIPA and MIPP in the EG were significantly higher than in the CG at all time points, except baseline. No significant differences between EG were found, but some trends were observable. Anteriorly, the higher the resistive load, the higher the increase in MIP. Posteriorly, 100% 1RM caused the highest values, followed by 60% and 80% 1RM. No detraining effects were measured. The degree of exercise load had a significant negative effect on the registered success rate. This RCT confirms the efficacy of TSE in healthy older adults. For MIPA and MIPP, TSE at a resistive load of 100% 1RM are the most efficient choice in this population, while lowering the resistive load will lead to an increased success rate. No detraining effects were registered.

High-power nano- and picosecond optoelectronic switches based on high-voltage silicon structures with p–n junctions: II. Energy efficiency

Energy efficiency of optoelectronic switches based on high-voltage silicon photodiodes, phototransistors or photothyristors and triggered-on by picosecond laser pulses has been studied for the first time. For given values of resistive load, amplitude and duration $t_R$ of voltage pulses it is shown that there exist optimal sets of values for the device area, energy and absorption coefficient for triggering illumination, which provide the maximal general efficiency of the switch about 0.92. All three types of switches have almost identical efficiencies at short $t_R$, and in case of long $t_R$ photothyristors possess a noticeable advantage among them.

Reciprocal reactions to different amounts of increased breathihg resistance

Objective: to study the role of the components of the stress-realizing and stress-limiting body systems at adaptation to different values breathing resistance. Materials and Methods: The study was conducted on healthy individuals (126 men), aged 18 to 38 years old of both sexes. Inspiratory breathing applied resistive load value of 20, 40 and 60%Pmmax. We measured the performance of hemostasis, immunity, oxidative activity, stress hormones. Results: Inspiratory load 40%Pmmax leads to activation of the anticoagulating mechanisms, increase antioxidant activity, stress-limiting effects and immunosuppressive changes; load 60%Pmmax caused opposite effects. Conclusions: The increased breathing resistance 40%Pmmax activates the stress-limiting systems; resistive load 60%Pmmax causes activation reciprocally organized stress-implement systems.

Experimental Study of Thermoelectric Generators

Thermoelectric generator is solid-state device which convert temperature difference, ∆T into electrical energy based on Seebeck effect phenomenon. The device has been widely used in self-powered system applications. This paper focuses on presentation of methodology for characterizing thermoelectric generators. The measurement of its behavior is performed by varying load resistances. A standard module of thermoelectric generator (TEC1-12710) is used in examination and an instrument setup consists of controllable heat source, controllable cooler, personal computer, data logger MCC DAQ USB-1208LS equipped with two sets of K-type thermocouples. The experiment is performed by measuring output voltage and output current in 4 values of temperature gradient by applying 10 values of resistive loads connected to the thermoelectric output wires. The common parameters studied in this research are output voltage, current and power. Generally, the relationship between parameters agrees with the basic theory and the procedure can be adopted for characterizing other type of thermoelectric generator.

Voltage Profile Analysis in Power Transmission System based on STATCOM using Artificial Neural Network in MATLAB/SIMULINK

This paper deals with Voltage Stability Analysis in a Power Transmission System with and without STATCOM using Artificial Neural Network in MATLAB/ SIMULINK. It is shown that trained Neural Network developed has excellent capabilities of forecasting which can be very useful in research. Voltage control and reactive power compensation in a weak distribution networks for integration of wind power is also represented in this paper. For dynamic reactive power compensation, when,STATCOM (Static Synchronous Compensator) is a used at a point of interconnection of wind farm and the network; the system absorbs the generated wind power for maintaining its voltage level. Voltage level of the system changes on changing the values of resistive loads connected to transmission line and using these voltages on bus 1 and bus2 on different values of loads a neural network is developed after training which can forecast voltage on bus 1 and bus 2 of the transmission line on any values of the resistive load connected to transmission line.

Linear Robust Output Regulation in a Class of Switched Power Converters

This article addresses the robust output regulation problem for a class of nonlinear switched power converters after its linearization by means of a change of the control vector variable. The methodology employs a dynamic state feedback control law and considers parametric uncertainty due to unknown values of resistive loads. Restrictions arising from the fact that the control gains exhibit fixed values are taken into account. The proposed technique is exemplified with the output voltage regulation of a Noninverting Buck-Boost converter and tested through realistic numerical simulations.

A Theory of Available Output and Optimum Operating Conditions for Triode Valves

The output characteristics of triode and pentode valves have been investigated in the past by many workers, using either the static method of plotting a whole family of curves, or the dynamic method of measurement with a harmonic analyzer: these have not, however, led to many simplifying generalizations, and are cumbersome and difficult methods if they are to be applied to each individual valve. In this paper, the form of the triode curves is first investigated experimentally, and the allowable limits of dynamic swing thus determined for any given per cent harmonic: on this basis, a series of expressions are mathematically developed giving the required output characteristics in terms of an easily obtained valve constant (i.e., the valve alternating-current resistance at V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</inf> = 100, V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</inf> = 0; this is the standard figure quoted by English manufacturers). Curves are given for output and correct plate current with various values of resistive load and of per cent harmonic limit, with or without conditions of limited anode dissipation. The case of the practical load with low direct-current resistance is examined, and the results are checked with a harmonic analyzer; the paper concludes with a few practical rules. It is hoped in a future paper to extend the analysis to cover push-pull circuits, the pentode valve, and the practical inductive load.