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Power quality measurements are essential to monitor, analyse and control the operation of smart grids within power systems. This work aims to develop and calibrate a PQ network analyser. As the penetration of non-linear loads connected to power systems is increasing every day, it is essential to measure power quality. In this sense, a power quality (PQ) analyser is based on the high-speed sampling of electrical signals in single-phase and three-phase electrical installations, which are available in real time for analysis using wireless Wi-Fi (Wireless-Fidelity) networks. The PQAE (Power Quality Analyser Embedded) power quality analyser has met the calibration standards for Class A devices from IEC 61000-4-30, IEC 61000-4-7 and IEC 62586-2. In this paper, a complete guide to the tests included in this standard has been provided. The Fast Fourier Transform (FFT) obtains the harmonic components from the measured signals and the window functions used reduce spectral leakage. The window size depends on the fundamental frequency of, intensity of and changes in the signal. Harmonic measurements from the 2nd to 50th harmonics for each phase of the voltage and each phase and neutral of the current have been performed, using the Fast Fourier transform algorithm with various window functions and their comparisons. PQAE is developed on an open-source platform that allows you to adapt its programming to the measurement needs of the users. [ABSTRACT FROM AUTHOR]

Foam targets have gained considerable importance over the last decade in laser–matter interaction. They find widespread applications such as in inertial confinement fusion and secondary sources for particles and radiation. At the same time, the advent of high repetition-rate laser systems, be they short-pulse in the tens of femtosecond regime or in the kilo-Joule nanosecond regime, calls for equally high repetition rate targetry systems. A well-established repetition-rate targetry system is the tape target. In this article, we present the successful marriage of a tape target delivery system with 3D-printed foam targets produced by two photon polymerization. [ABSTRACT FROM AUTHOR]

This document lists some challenges that researchers face when implementing transactive energy in weak power grids. These challenges often include high voltage fluctuations, limited generation, high line loadability, and unbalanced grids. The operation of transactive energy, as well as optimization techniques, are also considered, highlighting the performance and functionalities depending on power grid characteristics and market topology. Some of the most used optimization techniques for market clearing, considering the characteristics and topology, are presented as part of the research work.In addition, this paper compares different market topologies and highlights their advantages and challenges. Furthermore, this paper contains a brief description of the interoperability frameworks applied to a smart grid.As a result, it was determined that interoperability is necessary for the proper functioning of the grid. Moreover, all methods were found to be effective for their purpose from the user's point of view as each technique has different characteristics relevant to the user and the grid. It was concluded that it is convenient to combine the optimization techniques to consider different constraints in the market clearing. [ABSTRACT FROM AUTHOR]

The detection of irregularities such as a fraudulent branch line or a fault in short-length low voltage (LV) lines is of great interest for electricity supply companies as well as for other businesses. This paper describes and systematizes new techniques that afford in-depth knowledge of the occurrence of irregularities in these lines for the first time. Firstly, it has been characterized the response of a typical short-length tapped line by means of conventional time-domain reflectometry (TDR) technique as well as the additional new techniques proposed. These techniques are based on a conventional mathematical treatment of discrete-time signals. Moreover, they obviate the need for visual inspection at remote locations and only involve a moderate computational effort. Finally, it is exposed how fraudulent branch lines were detected in two real domestic supplies at the local electricity supply company by the proposed techniques. The first fraudulent line was detected in a long incoming main line buried in the ground by mean of the line-symmetry technique. The second one was detected in a short incoming main line located in building voids by the second echo and power spectral density methods. The accuracy of the results has been assessed in laboratory tests as well.

This paper gives the scientific background and basic premises that should guide the design of overcurrent protection in photovoltaic generators (PVGs). Overcurrent protection first requires a thorough knowledge of potential risk scenarios and how to evaluate them. Accordingly, this paper describes electrical faults that may pose a risk to PVG because of overcurrents. It also evaluates these faults with a dynamic PVG model. This simulation model provides a realistic vision of the thermal and electrical behavior of the PVG from which implications of overcurrent protection can be drawn. A field test on a functioning 68-kWp PVG showed the accuracy of the simulation results regarding the risk of overcurrents, and validated the model used in our study. Within this context, this paper discusses how protective measures in the IEC 60364-4-43 can be applied to PVG. Since the measures in this standard were specifically conceived for alternating current low voltage (AC LV) systems, the unique operational characteristics of a PVG now make it necessary to revise and adapt them.

The objective of this study was to determine the tissue composition of the carcass of growing New Zealand White rabbits based on the shoulder and neck traits (weight, meat and bone weights). Live weight and characteristics of dissected meat and bone tissues (neck, breast, rib, loin, shoulder, and leg) of 80 rabbits were recorded. Total carcass tissue weights (carcass fat weight, carcass meat weight - CMW, and carcass bone weight - CBW) were calculated and correlation and regression analyses were implemented. Shoulder, neck, shoulder meat, bone and neck meat were correlated (P < 0.0001 and < 0.001) with CMW and CBW. In conclusion, cut weights and tissue content of the shoulder and neck provided good predictions for total meat and bone weights of growing New Zealand White rabbits. [ABSTRACT FROM AUTHOR]

L3-HAPLS (High-repetition-rate Advanced Petawatt Laser System) at ELI (Extreme Light Infrastructure) Beamlines currently delivers 0.45 PW pulses (12 J in 27 fs) at 3.3 Hz repetition rate. A fresh target surface for every shot was placed at the laser focus using an in-house tape target system designed to withstand large laser intensities and energies. It has been tested for different material thicknesses (25 and 7.6 µm), while L3-HAPLS delivered laser shots for energies ranging from 1 to 12 J. A technical description of the tape target system is given. The device can be used in diverse geometries needed for laser–matter interaction studies by providing an ≈300° free angle of view on the target in the equatorial plane. We show experimental data demonstrating the shot-to-shot stability of the device. An x-ray crystal spherical spectrometer was set up to measure the Kα yield stability, while a GHz H-field probe was used to check the shot-to-shot electromagnetic pulse generation. Finally, we discuss short and mid-term future improvements of the tape target system for efficient user operation. [ABSTRACT FROM AUTHOR]

Appropriate supplementation of trace minerals is fundamental to enhance the metabolic status of growing animals and promote an adequate expression of genetic potential. Zinc (Zn) is an essential mineral fundamental in many biological processes that are related to growth, energy balance and immunity. The aim of the present study was to analyse the effect of Zn supplementation on growth parameters in small ruminants by using a meta-analytic approach. Sources of heterogeneity were explored using a meta-regression analysis. The final database was integrated from a total of 53 trials. Only indexed articles that provided an effect size measure, variability measure, sample size and randomisation of the procedure were considered. The dependent variables considered for the study were average daily gain (ADG), dry-matter intake (DMI), feed conversion ratio (FCR), final bodyweight, and glucose blood concentration. The exploratory variables included species (sheep and goat), breed, production level, Zn source and dosage. The 'meta' package in R statistical software was used to conduct the meta-analyses. For response variables that showed substantial heterogeneity (I 2 > 50%), mixed-effect models (meta-regression analysis) were constructed to explore the sources of heterogeneity using the 'Metafor' package. DMI was higher in animals supplemented with Zn (>21.08 g/day, P = 0.0001). Breed, species, production level, and dosage reduced heterogeneity of DMI response from I 2 = 84.8 to I 2 = 48.1%. Zn-supplemented animals showed higher ADG (17.39 g/day, P = 0.001), which was affected by species, breed dosage and Zn-source. Zn supplementation improved feed efficiency, with lower values of FCR (–1.56 g/g, P < 0.0001). There was a positive relationship between the dosage and effect size in all outcome variables (P < 0.05). Zn-proteinate showed the best response in both species to ADG, FCR and final body weight. Our findings of the systematic review concluded that dietary Zn supplementation improves growth performance in small ruminants and their level of response is influenced mainly by species, production level, and Zn-source and dosage. Zinc (Zn) is an essential mineral fundamental in many biological processes related with growth, energy balance and immunity. The aim of the present study was to analyse the effect of Zn supplementation on growth parameters in small ruminants by using a meta-analytic approach. We concluded that dietary Zn supplementation improves growth performance of small ruminants. The level of response is influenced mainly by species, production level, Zn source and dosage rate. [ABSTRACT FROM AUTHOR]

Heat stress and a high metabolic rate of broilers increase the production of reactive oxygen species, which must be removed by antioxidants to prevent oxidative stress. Selenium (Se) is a potent antioxidant as it is a structural part of glutathione peroxidase (GPx). Dietary supplementation of Se can help reduce the oxidative stress caused by heat-stress conditions. The aim was to evaluate the effect of Se supplementation on the performance and antioxidant status of broilers under heat stress, by using a meta-analysis approach, and to quantify the contribution to heterogeneity of the explanatory variables through a meta-regression procedure. A database of 74 trials was created from 56 published studies that met the following inclusion criteria: papers that reported a measure of effect size, sample size, measure of variability and random procedure. The response variables were GPx and malondialdehyde concentrations, DM intake, average daily gain, and feed conversion rate. Broiler line, Se source, and dosage, heat-stress level, days of experimentation, sample source (blood, liver or meat) and basal Se concentration were considered to be explanatory variables. All statistical analyses were performed in R software, by using the 'meta' and 'Metafor' packages for meta-analysis and meta-regression respectively. High concentrations of GPx were found in Se-supplemented broilers (>1.76; P = 0.001), in comparison to control groups. However, when the random model was applied to GPx studies, it showed high heterogeneity (I 2 = 95.4%), which was reduced (I 2 = 61.5) when heat-stress temperature, Se source and its dosage and tissue sample were included as covariates in the meta-regression analysis. The highest standard mean difference of GPx was founded in studies that reported supplementation with inorganic Se sources (2.92), in comparison to supplementation with organic and nano-Se sources (1.66 and 1.44 respectively). The standard mean differences of malondialdehyde and feed conversion rate were significantly lower (<0.66 and <0.11 respectively) in supplemented broilers. Heterogeneity of all variables decreased when the explanatory variables were included in the mixed-regression model. Our findings confirmed that Se supplementation improves the broiler's antioxidant status and productive performance. However, the response level was affected by dosage and source of Se and the level of heat stress. The heat stress has been associated with detrimental effects of productive performance in broilers. Selenium supplementation is a viable option to reduce the effect of heat stress on oxidative status. However, its response level is influenced by dosage and source of selenium supplementation. [ABSTRACT FROM AUTHOR]

The design and the early commissioning of the ELI-Beamlines laser facility's 30 J, 30 fs, 10 Hz HAPLS (High-repetition-rate Advanced Petawatt Laser System) beam transport (BT) system to the P3 target chamber are described in detail. It is the world's first and with 54 m length, the longest distance high average power petawatt (PW) BT system ever built. It connects the HAPLS pulse compressor via the injector periscope with the 4.5 m diameter P3 target chamber of the plasma physics group in hall E3. It is the largest target chamber of the facility and was connected first to the BT system. The major engineering challenges are the required high vibration stability mirror support structures, the high pointing stability optomechanics as well as the required levels for chemical and particle cleanliness of the vacuum vessels to preserve the high laser damage threshold of the dielectrically coated high-power mirrors. A first commissioning experiment at low pulse energy shows the full functionality of the BT system to P3 and the novel experimental infrastructure. [ABSTRACT FROM AUTHOR]

Purpose: Image‐guided radiotherapy (IGRT) improves tumor control but its intensive use may entrain late side effects caused by the additional imaging doses. There is a need to better quantify the additional imaging doses, so they can be integrated in the therapeutic workflow. Currently, no dedicated software enables to compute patient‐specific imaging doses on a wide range of systems and protocols. As a first step toward this objective, we propose a common methodology to model four different kV‐imaging systems used in radiotherapy (Varian's OBI, Elekta's XVI, Brainlab's ExacTrac, and Accuray's Cyberknife) using a new type of virtual source model based on Monte Carlo calculations. Methods: We first describe our method to build a simplified description of the photon output, or virtual source models (VSMs), of each imaging system. Instead of being constructed using measurement data, as it is most commonly the case, our VSM is used as the summary of the phase‐space files (PSFs) resulting from a first Monte Carlo simulation of the considered x‐ray tube. Second, the VSM is used as a photon generator for a second MC simulation in which we compute the dose. Then, the proposed VSM is thoroughly validated against standard MC simulation using PSFs on the XVI system. Last, each modeled system is compared to profiles and depth‐dose‐curve measurements performed in homogeneous phantom. Results: Comparisons between PSF‐based and VSM‐based calculations highlight that VSMs could provide equivalent dose results (within 1% of difference) than PSFs inside the imaging field‐of‐view (FOV). In contrast, VSMs tend to underestimate (for up to 20%) calculated doses outside of the imaging FOV due to the assumptions underlying the VSM construction. In addition, we showed that the use of VSMs allows reducing calculation time by at least a factor of 2.8. Indeed, for identical simulation times, statistical uncertainties on dose distributions computed using VSMs were much lower than those obtained from PSF‐based calculations. Conclusions: For each of the four imaging systems, VSMs were successfully validated against measurements in homogeneous phantoms, and are therefore ready to be used for future preclinical studies in heterogeneous or anthropomorphic phantoms. The cross system modeling methodology developed here should enable, later on, to estimate precisely and accurately patient‐specific 3D dose maps delivered during a large range of kV‐imaging procedures. [ABSTRACT FROM AUTHOR]

The new definitions together with a complete characterization of all eban numbers are presented. The eban numbers are those that do not contain the letter e in its name.

At present, electric vehicles are charged at home at night when lower off-peak rates could apply. The purpose of this pilot project is to demonstrate the viability of providing renewable power charging services for electric vehicles at railway station parking lots for commuters during the day. The power needed to feed the charging station comes from a photovoltaic system as well as from the regenerative braking of a 25-kV AC railway traction system (RTS) and a 3-kV DC RTS. The design of the proposed DC microgrid for the charging station also involves an energy storage system (ESS) (battery of variable size and supercapacitor) and the connection to a secondary distribution network (SDR). The paper analyses the two most challenging technical issues: (1) the strategy of power management and converter control; (2) the impact of the size of the ESS. Although an increase in the size of ESS benefits the charge from renewable power, this increases the total investment inevitably. The smart strategy developed from power management, based on DC bus sensing, aims at maximizing the usage of available renewable power by mitigating the impact of charging station on the SDR. [ABSTRACT FROM PUBLISHER]

DC-DC converters for fuel cell applications require wide voltage range operation due to the unique fuel cell characteristic curve. Primary parallel isolated boost converter (PPIBC) is a boost derived topology for low voltage high current applications reaching an efficiency figure up to 98.2 %. This paper proposes a new operation mode for extending the input and output voltage range in PPIBC. The proposed solution does not modify PPIBC power stage; the converter gain is modified by short-circuiting one of the parallel connected primary windings in the topology. The change in operation mode divides by two the converter input-to-output voltage gain. This allows covering the conditions when the fuel cell stack operates in the activation region (maximum output voltage) and increases the degrees of freedom for converter optimization. The transition between operating modes is studied because represents a change in the converter steady-state conditions. A solution is proposed based on pre-calculation of the duty cycle prior to the transition. [ABSTRACT FROM AUTHOR]

The volumetric mass transfer coefficient and the power number are some of the most important parameters in engineering; they are needed to scale up the equipment and/or processes. Besides, the volumetric mass transfer coefficient (kLa) for the different operational conditions (aeration and agitation rates) were obtained in the culture medium free of microorganisms and for the fermentation, such conditions were found for the most production of bikaverin. The Reynolds number and the power were determined for different treatments in bioreactor. The results in the bioreactor showed that high speed of agitation and low aeration rate favor bikaverin production, the highest production was 112.23 mgL-1 with the condition of 0.1 vvm and 500 rpm was found on the average kLa during the fermentation of 41.42 h-1, whereas, to the culture medium without microorganisms the kLa increases proportionally to the increase of the agitation and aeration rates. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the goodness of fit of four lactation curve models: Wood's Gamma model (WD), Wilmink (WL), and Pollott's multiplicative two (POL2) and three parameters (POL3) and to determine the environmental factors affecting the complete lactation curve of F1 dairy sheep under organic management. A total of 5,382 weekly milk yields records from 150 ewes, under organic management were used. Residual mean square (RMS), determination coefficients (R2), and correlation (r) analysis were used as an indicator of goodness of fit for each model. WL model best fitted the lactation curves as indicated by the lower RMS values (0.019), followed by WD (0.023), POL2 (0.025) and POL3 (0.029). The four models provided total milk yield (TMY) estimations that were highly correlated (0.93 to 0.97) with observed TMY (89.9 kg). The four models under estimated peak yield (PY), whereas POL2 and POL3 gave nearer peak time lactation estimations. Ewes lambing in autumn had higher TMY and showed a typical curve shape. Higher TMY were recorded in second and third lambing. Season of lambing, number of lambing and type of lambing had a great influenced over TMY shaping the complete lactation curve of F1 dairy sheep. In general terms WL model showed the best fit to the F1 dairy sheep lactation curve under organic management. [ABSTRACT FROM AUTHOR]