Line Frequency Research Articles

Deletion of Gαq/11 or Gαs Proteins in Gonadotropes Differentially Affects Gonadotropin Production and Secretion in Mice.

Gonadotropin-releasing hormone (GnRH) regulates gonadal function via its stimulatory effects on gonadotropin production by pituitary gonadotrope cells. GnRH is released from the hypothalamus in pulses and GnRH pulse frequency differentially regulates follicle-stimulating hormone (FSH) and luteinizing hormone (LH) synthesis and secretion. The GnRH receptor (GnRHR) is a G protein-coupled receptor that canonically activates Gα q/11-dependent signaling on ligand binding. However, the receptor can also couple to Gα s and in vitro data suggest that toggling between different G proteins may contribute to GnRH pulse frequency decoding. For example, as we show here, knockdown of Gα s impairs GnRH-stimulated FSH synthesis at low- but not high-pulse frequency in a model gonadotrope-derived cell line. We next used a Cre-lox conditional knockout approach to interrogate the relative roles of Gα q/11 and Gα s proteins in gonadotrope function in mice. Gonadotrope-specific Gα q/11 knockouts exhibit hypogonadotropic hypogonadism and infertility, akin to the phenotypes seen in GnRH- or GnRHR-deficient mice. In contrast, under standard conditions, gonadotrope-specific Gα s knockouts produce gonadotropins at normal levels and are fertile. However, the LH surge amplitude is blunted in Gα s knockout females and postgonadectomy increases in FSH and LH are reduced both in males and females. These data suggest that GnRH may signal principally via Gα q/11 to stimulate gonadotropin production, but that Gα s plays important roles in gonadotrope function in vivo when GnRH secretion is enhanced.

Influence of plasma-activated water (PAW) on the germination of radish, fenugreek, and pea seeds

The present work is focused on investigating the effect of plasma-activated water (PAW) on the seed germination and seedling growth of radish, fenugreek, and pea seeds. A home-made gliding arc discharge (GAD) reactor generated in air under atmospheric pressure and operating at 50 Hz line frequency is used for water activation. PAW was prepared by exposing deionized water to GAD for 5, 10, 15, and 20 min. As a result of plasma treatment, deionized water showed substantial changes in physical characteristics such as pH and electrical conductivity along with chemical parameters such as nitrites, nitrates, and ammonia. The effect on germination was evaluated based on the fraction of germinated seeds and their length at 7 and 12 days after treatment. Seeds irrigated with PAW resulted in a higher imbibition rate than those irrigated by deionized water. When the seeds were irrigated with PAW, the germination parameters such as final germination rate, mean germination rate, coefficient of velocity of germination, germination index, and growth parameters such as shoot/seedling length and vigor index increased. In conclusion, PAW may be utilized to increase the germination rate of seeds.

LLC and CLLC Resonant Converters Based DC Transformers (DCXs): Characteristics, Issues, and Solutions

Conventional line frequency transformers have the disadvantages of large volume and low efficiency. The medium or high frequency transformers based on power converters can achieve high power conversion with small footprint have drawn popularity in numerous industrial applications. Unregulated resonant converters, LLC and CLLC resonant converters, with fixed voltage conversion ratio operating at resonant frequency, which are also known as DC transformers (DCXs), are attractive owning to their high efficiency characteristic. Nevertheless, there are issues associated with DCXs in real applications. Regulation capability and automatic resonant frequency tracking capability are the two most important issues for DCXs. The main work of this paper is to characterize the resonant converters based DCXs, and overview the issues and solutions associated with DCXs. Guidelines can be provided for researchers and engineers when designing the resonant converters based DCXs.

A single-stage full bridgeless boost half-bridge AC/DC converter with bidirectional switch

This paper proposes an isolated full bridgeless single stage alternating current-direct current (AC-DC) converter. The proposed converter integrates the operation of a pure bridgeless power factor correction with input boost inductor cascaded with center-tap transformer and half bridge circuit. In addition, the bidirectional switch can be driven with single control signal which further simplifies the controller circuit. It is also proved that this converter reduces the total number of components compared to some conventional circuit and semi-bridgeless circuit topologies. The circuit operation of the proposed circuit is then confirmed with the small signal model, large signal model, circuit simulation and then verified experimentally. It is designed and tested at 115 Vac, 50 Hz of input supply, and 20 Vdc output voltage with maximum output power of 100 W. In addition, the crossover distortion at the input current is minimize at high input line frequency.

Multifragmentary patellar fracture has a distinct fracture pattern which makes coronal split, inferior pole, or satellite fragments

The present study aimed to map the location and frequency of fracture lines on the coronal articular and sagittal planes in multifragmentary patellar fractures. 66 multifragmentary patellar fractures were digitally reconstructed using the 3D CT mapping technique. The coronal articular surface and midsagittal fracture maps were produced by superimposing each case over a single template. Each fracture line was classified based on the initial displacement and orientation. We evaluated the frequency and direction of the fracture line, coronal split fragment area, and satellite and inferior pole fragment presence. Coronal articular surface fracture mapping identified primary horizontal fracture lines between the middle and inferior one-third of the articular surface in 63 patients (95.4%). Secondary horizontal fracture lines running on the inferior border of the articular facet were confirmed (83.3%). Secondary vertical fracture lines creating satellite fragments were mostly located on the periphery of the bilateral facet. Midsagittal fracture mapping of primary and secondary horizontal fracture lines with the main coronal fracture line revealed a predominantly X-shaped fracture map. The consequent coronal split fragment and inferior pole fracture were combined in most cases. In conclusion, the multifragmentary patellar fracture has a distinct pattern which makes coronal split, inferior pole, or satellite fragments.

Analysis of wind farm penetration on power swing detection in distance relays

Distance protection plays an essential role in the protection of sub-transmission and transmission lines in power systems. However, power swings have occasionally led to the mal-operation of this type of protection. A significant number of large disturbances, such as blackouts, start with power swings. Thus, improving the circumstances leading to this disruptive phenomenon becomes a great priority. Nowadays, the wind power share of worldwide electricity generation and the use of wind farms have increased. As a result, to predict future events, it is necessary to assess the network in the presence of these renewable sources. In this paper, the effects of the wind resources penetration on power swing have been evaluated. Simulations and analyses have been performed in PSCAD/EMTDC and MATLAB environments, respectively. To provide a comprehensive analysis, maximum power passing through the transmission line and power swing frequency have been utilised as criteria. The results show that wind farms presented acceptable behaviour in the presence of power swing and instability. Therefore, in view point of a power swing, induction generator based wind power plants, compared to synchronous generators, led to better overall conditions. Finally, the effect of fixed and variable speed wind turbines on power swing is compared.

Dual-comb hyperspectral digital holography

Holography1 has always held special appeal as it is able to record and display spatial information in three dimensions2–10. Here we show how to augment the capabilities of digital holography11,12 by using a large number of narrow laser lines at precisely defined optical frequencies simultaneously. Using an interferometer based on two frequency combs13–15 of slightly different repetition frequencies and a lensless camera sensor, we record time-varying spatial interference patterns that generate spectral hypercubes of complex holograms, revealing the amplitudes and phases of scattered wave-fields for each comb line frequency. Advancing beyond multicolour holography and low-coherence holography (including with a frequency comb16), the synergy of broad spectral bandwidth and high temporal coherence in dual-comb holography opens up novel optical diagnostics, such as precise dimensional metrology over large distances without interferometric phase ambiguity, or hyperspectral three-dimensional imaging with high spectral resolving power, as we demonstrate with molecule-selective imaging of an absorbing gas.

Joint voltage and frequency predictive controllers for distributed generation plants

The paper determines the effect of proposed joint voltage and frequency predictive controllers for distributed generation (DG) plants on quality indicators characterizing the control process in different operating modes of power supply systems. The studies are conducted in the MatLab environment (Simulink and SimPowerSystems simulation packages) employing control engineering methods. It is proposed to design and adjust joint predictive controllers by determining the resonant frequency of oscillations for the master generator rotor. This approach provides better quality indicators of voltage and frequency control in power supply systems while maintaining the same settings for the controllers of DG plants. With an additional load in an isolated power supply system, the maximum voltage sag is found to be 1.75 times lower than for local predictive control and 3.5 times lower as compared to the use of conventional controllers. For the specified mode, predictive controllers enable a threefold reduction in the transient time between rotor rotational speeds in a synchronous generator. In the start mode of a powerful electric motor, the predictive controllers of synchronous generators in the power supply system enable a 1.5 times reduction in voltage sag, with a 1.4 times reduction in overvoltage following its start. In the case of a short-term three phase short-circuit, joint predictive controllers allow a 1.5 times decrease in transient time and a 2.3 times decrease in the overshoot of power line frequency as compared to local control. In addition, frequency oscillation in the power system is also reduced. Similar effects are observed in other operating modes of the considered power supply systems equipped with DG plants. The performed dynamic simulation confirms the effectiveness of using joint voltage and frequency predictive controllers for DG plants, which consists in a positive impact on the quality of processes involved in controlling the parameters of power supply systems in various operating modes.

A Phase-Ib/II Clinical Evaluation of Ponatinib in Combination with Azacitidine in FLT3-ITD and CBL-Mutant Acute Myeloid Leukemia (PON-AZA study)

A Phase-Ib/II Clinical Evaluation of Ponatinib in Combination with Azacitidine in FLT3-ITD and CBL-Mutant Acute Myeloid Leukemia (PON-AZA study)

Sugarcane Smut, Caused by Sporisorium scitamineum, a Major Disease of Sugarcane: A Contemporary Review.

Sugarcane smut caused by the fungus Sporisorium scitamineum is one of the major diseases of sugarcane worldwide, causing significant losses in productivity and profitability of this perennial crop. Teliospores of this fungus are airborne, can travel long distances, and remain viable in hot and dry conditions for >6 months. The disease is easily recognized by its long whiplike sorus produced on the apex or side shoots of sugarcane stalks. Each sorus can release ≤100 million teliospores in a day; the spores are small (≤7.5 µ) and light and can survive in harsh environmental conditions. The airborne teliospores are the primary mode of smut spread around the world and across cane-growing regions. The most effective method of managing this disease is via resistant varieties. Because of the complex genomic makeup of sugarcane, selection for resistant traits is difficult in sugarcane breeding programs. In recent times, the application of molecular markers as a rapid tool of discarding susceptible genotypes early in the selection program has been investigated. Large effect resistance loci have been identified and have the potential to be used for marker-assisted selection to increase the frequency of resistant breeding lines in breeding programs. Recent developments in omics technologies (genomics, transcriptomics, proteomics, and metabolomics) have contributed to our understanding and provided insights into the mechanism of resistance and susceptibility. This knowledge will further our understanding of smut and its interactions with sugarcane genotypes and aid in the development of durable resistant varieties.

Calculation of contrast for computer simulated resolution chart image

The work is devoted to the analysis of the resolution chart image created with the Image Simulation mode of ZEMAX software. The changes in image quality are simulated using the model of Helios-44M-4 photographic objective lens. The research is conducted for monochromatic light conditions and computer simulated resolution test chart as an object for the lens with different chart positions. An axial beam and an off-axis beam that corresponds to the maximum object space field angle are analyzed. The calculation of contrast of the simulated resolution chart images is made modeling different spatial frequencies of the chart lines. The contrast is calculated in three ways. The first way uses the maximum and minimum values of the image illumination, and the second and third ways are based on the integral values of the illumination of black and white lines, calculated with the method of rectangles and the method of trapeziums, respectively. Having been calculated the values of contrast are compared with the theoretical values of the diffraction modulation transfer function obtained with ZEMAX.

Engines of change: Transposable element mutation rates are high and variable within Daphnia magna.

Transposable elements (TEs) represent a major portion of most eukaryotic genomes, yet little is known about their mutation rates or how their activity is shaped by other evolutionary forces. Here, we compare short- and long-term patterns of genome-wide mutation accumulation (MA) of TEs among 9 genotypes from three populations of Daphnia magna from across a latitudinal gradient. While the overall proportion of the genome comprised of TEs is highly similar among genotypes from Finland, Germany, and Israel, populations are distinguishable based on patterns of insertion site polymorphism. Our direct rate estimates indicate TE movement is highly variable (net rates ranging from -11.98 to 12.79 x 10-5 per copy per generation among genotypes), differing both among populations and TE families. Although gains outnumber losses when selection is minimized, both types of events appear to be highly deleterious based on their low frequency in control lines where propagation is not limited to random, single-progeny descent. With rate estimates 4 orders of magnitude higher than base substitutions, TEs clearly represent a highly mutagenic force in the genome. Quantifying patterns of intra- and interspecific variation in TE mobility with and without selection provides insight into a powerful mechanism generating genetic variation in the genome.

Ripple Power Steering of HFL-TPC Connected VSI for PV-BESS/EV Applications

This paper presents low frequency ripple power steering control strategies for a power conversion topology that comprises of a high frequency linked three port converter (HFL-TPC) and a voltage source inverter (VSI) for PV-BESS/EV applications. The proposed topology has three interfaces which can be connected with a photovoltaic (PV) port, battery energy storage systems (BESS) and/or electric vehicles (EVs) port, and a four-quadrant ac port. The proposed topology inherently exhibits double line frequency (DLF) power fluctuation that needs to be decoupled and steered away from the PV port. In this paper, we have developed and demonstrated two control strategies to deal with the DLF ripple. The first control strategy utilizes loop gain of the closed loop control system to decouple the DLF power, however a residual DLF power still exists at the ac port. To completely decouple the DLF fluctuations, an improved sequence based control strategy is proposed where the DLF voltage components are converted into positive and negative sequence components and controlled separately on their respective synchronous reference frames. To verify the practical feasibility of the proposed low frequency ripple power steering control strategies, a 40 V, 400 W HFL-TPC is built and tested. Experimental results show that the proposed ripple power steering control strategies can decouple the DLF power fluctuation and selectively steer it to the BESS/EV port as DLF power fluctuation is undesirable at the PV port. A comparative results reveal that sequence based control strategy show higher degree of DLF ripple suppression.

Enzymatic activity monitoring through dynamic nuclear polarization in Earth magnetic field

Cost-effective and portable MRI systems operating at Earth-field would be helpful in poorly accessible areas or in developing nations. Furthermore Earth-field MRI can provide new contrasts opening the way to the observation of pathologies at the biochemical level. However low-field MRI suffers from a dramatic lack in detection sensitivity even worsened for molecular imaging purposes where biochemical specificity requires detection of dilute compounds. In a preliminary spectroscopic approach, it is proposed here to detect protease-driven hydrolysis of a nitroxide probe thanks to electron-nucleus Overhauser enhancement in a home-made double resonance system in Earth-field. The combination of the Overhauser effect and the specific enzymatic modification of the probe provides a smart contrast reporting the enzymatic activity. The nitroxide probe is a six-line nitroxide which lines are shifted according to its substrate/product state, which requires quantum mechanical calculations to predict EPR line frequencies and Overhauser enhancements at Earth field. The NMR system is equipped with a 13-mT prepolarization coil, a 153-MHz EPR coil and a 2-kHz NMR coil. Either prepolarized NMR or DNP-NMR without prepolarization provide NMR spectra within 3 min. The frequency dependence of Overhauser enhancement was in agreement with theoretical calculations. Protease-mediated catalysis of the nitroxide probe could only be measured through the Overhauser effect with 5 min time resolution. Future developments shall open the way for the design of new low-field DNP-MRI systems.

A risk management framework for power distribution networks undergoing a typhoon disaster

With the increasing distribution network accidents caused by typhoon disasters, risk management in typhoon scenarios is necessary. A risk management framework for power distribution networks (PDNs) undergoing a typhoon disaster is proposed. First, a risk prediction model of the PDN under typhoon conditions based on the Batts model is developed to predict the loss of load risk (LLR) index and economic loss risk (ELR) index of the PDN before the typhoon lands. Then, a vulnerability index of overhead lines, considering the failure frequency of specific overhead lines and their load importance, is introduced for use in a weak link identification model to identify weak links in the PDN. Finally, a two-time-step risk relief model based on typhoon forecast information and the identified weak links is developed to allocate PDN relief materials to reduce the LLR and ELR during a typhoon disaster. An IEEE RBTS BUS6 system is employed as a test system to verify the risk management strategy. The vulnerability index proposed by the strategy considers both the importance of load and line failure. The risk management strategy adopts a two-time-step model, which reduces the impact of meteorological forecast errors and enables more efficient use of materials. The results show that the proposed framework can take more effective use of relief materials to reduce the loss of PDNs compared with the traditional strategy.

Quasi-Two-Level Bridgeless PFC Rectifier for Cascaded Unidirectional Solid State Transformer

With the advancements in wide-bandgap power devices, the solid state transformer (SST) becomes attractive to industry due to its merits of high efficiency and power density, modularity, and scalability. However, the complexity and cost remain obstacles to widespread adoption. This article presents a unidirectional SST with a cascaded three-level bridgeless power factor correction rectifier stage and a series-half-bridge (SHB) <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> dc–dc stage, which is simpler and more cost effective than its bidirectional counterpart. The quasi-two-level (Q2L) modulation method is proposed for the three-level bridgeless PFC rectifier. In contrast with the three-level modulation, the Q2L modulation almost eliminates the neutral-point (NP) voltage ripple at line frequency, resulting in much less dc-link capacitor volume. Further, the only safe switching sequence to implement the Q2L modulation is identified and analyzed. The NP voltage shall be balanced by the SHB <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> dc–dc stage for proper operation of the system. A phase-shift-based three-level operation mode is proposed for the SHB <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> converter to balance the NP voltage. The proposed methods are experimentally verified on a 10 kW silicon carbide-based three-level converter cell and a single-phase multicell SST prototype.

Surface Treatment of Handmade Lokta Paper by Atmospheric Pressure Dielectric Barrier Discharge Using 50 Hz Line Frequency

The discharge was generated between two rectangular parallel-plate copper electrodes using a sinusoidal voltage of 12.8 kV (rms) of frequency 50 Hz and characterized using electrical and optical measurements. The effects of the discharge on the wicking property and weight loss of Lokta paper were studied respectively by the wicking test and gravimetric method. The estimated value of electron density and electron temperature in the discharge were 8.47×108 cm-3 and 1.29 eV. The results showed a significant improvement in water absorption ability and considerable weight loss (%) in Lokta paper after the plasma treatment.

IoT based Controlling of Power Grid

An electric network, electric grid, or electricity network is an integrated electricity supply network for producers to consumers. It consists of electricity producing stations. The main objective of this study is to monitor the electricity grid system process, disclose this system at a dangerous level, monitor the current line, and reduce conventional systems expenses. From anywhere on the Internet, we can monitor. We can do it also if a system is enabled or disabled. It uses an electrical microcontroller to monitor a single-phase electrical device using Arduino to read sensor voltage and current and then communicate measured data via a new Android application for wireless monitoring. It enables the monitoring of several basic power quality parameters of basic voltage. The technology also determines the line frequency and power factor.

IoT based Controlling of Power Grid

An electric network, electric grid, or electricity network is an integrated electricity supply network for producers to consumers. It consists of electricity producing stations. The main objective of this study is to monitor the electricity grid system process, disclose this system at a dangerous level, monitor the current line, and reduce conventional systems expenses. From anywhere on the Internet, we can monitor. We can do it also if a system is enabled or disabled. It uses an electrical microcontroller to monitor a single-phase electrical device using Arduino to read sensor voltage and current and then communicate measured data via a new Android application for wireless monitoring. It enables the monitoring of several basic power quality parameters of basic voltage. The technology also determines the line frequency and power factor.

Ateş Böceği Algoritması Kullanılarak Toplu Taşıma Frekans Optimizasyonu ve Parametrelerinin Değerlendirilmesi

ABSTRACT: Over the last few decades, rapidly growing cities in terms of population and land use have led to many transportation-based problems such as longer travel times, traffic congestion, traffic crashes, and air and noise pollution. Increasing the modal share of transit systems appears to be one of the most effective methods to solve transportation-based problems. However, transit systems, particularly in countries having limited resources, should be used efficiently to achieve sustainable urban mobility. Even only adjusting frequencies of transit lines, with no infrastructure investment cost requirements, can provide a more efficient transit system. In this paper, a transit frequency setting model based on the Firefly Algorithm (FA), which is a relatively new metaheuristic, for the transportation network design problems is presented to minimize total user cost under a fleet size constraint. The proposed model is performed on a 10-route Mandl’s Test Network using different combinations of parameters to demonstrate the effect of parameter values on the solution quality. After that, the best solution of 30 solutions obtained by the calibrated parameter values is compared to the existing frequency set of the 10-route transit network. The results show that the FA can obtain better frequency sets by selecting the proper values for the parameters.