Research of Bipolar HVDC Transmission Lines Based on Traveling Wave Differential Protection

The principle of the traveling wave based differential protection for bipolar HVDC transmission lines is proposed in the paper. Unlike the traditional current differential protection, the quantity of current is replaced by the quantity of the traveling wave for comparison. The traveling wave at the remote end is transferred to the local end for comparison to the local traveling wave. For the bipolar DC transmission lines, the polar-mode (aerial mode) traveling waves are employed to establish the discriminative criterion. The ground-mode traveling waves are utilized for faulty line detector for bipolar operation modes. The entire protection scheme is simulated in PSCAD/EMTDC associated with the standard ±500kV HVDC transmission system. The simulation results show that the new protection has the advantages of higher sensitivity, reliability and security. The fault resistance can be coverd by the traveling wave based differential protection reaches to 500 Ohm.  DOI: http://dx.doi.org/10.11591/telkomnika.v11i12.3700

A Novel Traveling Wave Based Differential Protection for Distributed Parameter Line

Traditional current differential protection is based on Kirchhoff’s Law, certainly is severely influenced by the distributed capacitance current. A new traveling wave based differential protective principle is proposed by employing the characteristics of current traveling waves for the distributed parameter line model. There are fixed propagation relations between traveling waves of terminals as the line is healthy or the fault is external, however, the relationship is broken for the internal faults. The protective criterion and scheme are established by this character. The key technique is to quickly calculate the propagating traveling waves from the other terminal on line. The coefficients of propagation function from one terminal to another are obtained by using orthogonal projection methods. The principle and algorithm need not high sampling frequency, are adaptive for not only fundamental component but the transient components, as well as is not sensitive to setting parameters. The large amounts of ATP simulation tests show that the protective scheme and algorithm is simple with high reliability, security, speedy and sensitivity. DOI: http://dx.doi.org/10.11591/telkomnika.v11i9.3254

Comparative Study and Simulation of Soil Infiltration Performance in Open Green Space

Soil infiltration is important for urban open space to exert sponge benefits, and its permeability characteristics are influenced by physical and chemical properties. To determine the characteristics and differences of soil permeability in different open spaces, we used the cutting-ring method to measure the soil infiltration process in four types of open space. The effects of physicochemical properties on soil infiltration were analyzed through comparison. The infiltration process of the four types of green spaces was fitted on the basis of Kostiakov and Philip infiltration models, and the suitability of the models was discussed. The water infiltration process shows that the law of initial infiltration rate > average infiltration rate > stable infiltration rate. The stable infiltration rate of each green space ranges from 2.46 mm/min to 3.60 mm/min, and the ranking is as follows: park > square > block > other shared space. The determination coefficient of the Kostiakov model for the soil infiltration process of the four types of green space is higher than 0.94, which is suitable to describe the soil infiltration characteristics of green space in the study area. The soil infiltration performance of green space shows a negative correlation with soil bulk density and moisture content but a positive correlation with non-capillary porosity. This study provides a reference for the construction of sponge cities and ecological hydrological observation

The Research of Digital Algorithm Based on Frequency-Dependent Transmission Lines

The algorithm for obtaining the discrete response of popagation function for frequency dependent parameter line is presented. Consider a minimum sampling period Tsm, that is, the highest frequency fH=1/(2Tsm) in the signal is taken into account. The impedance z(w) and the admittance y(w) are obtained in the frequency range of [0,fH] by employing the Carson’s formula. The propagation function at each frequency point is subsequently obtained, the impulse response in discrete time domain is then obtained using Poision Sum Formula. In order to avoid the long length of impulse reponse under the higher sampling frequency, the poles and zeros of z transform of discrete propagation function are evaluated by the Prony’s method. Subsequently, the coeffcients of the discrete infinite impulse response of propagation function are obtained. Using these coefficients the wave transfer sources can be easily computed by discrete convolution operation. The simulation tests show that the results using the propsed method is accurate, the error is not more than 1% in contrast of the results generated by EMTP. DOI: http://dx.doi.org/10.11591/telkomnika.v11i5.249

Effects of epigallocatechin-3-gallate on bovine oocytes matured

Objective Epigallocatechin-3-gallate (EGCG) is a major ingredient of catechin polyphenols and is considered one of the most promising bioactive compounds in green tea because of its strong antioxidant properties. However, the protective role of EGCG in bovine oocyte in vitro maturation (IVM) has not been investigated. Therefore, we aimed to study the effects of EGCG on IVM of bovine oocytes. Methods Bovine oocytes were treated with different concentrations of EGCG (0, 25, 50, 100, and 200 μM), and the nuclear and cytoplasmic maturation, cumulus cell expansion, intracellular reactive oxygen species (ROS) levels, total antioxidant capacity, the early apoptosis and the developmental competence of in vitro fertilized embryos were measured. The mRNA abundances of antioxidant genes (nuclear factor erythriod-2 related factor 2 [NRF2], superoxide dismutase 1 [SOD1], catalase [CAT], and glutathione peroxidase 4 [GPX4]) in matured bovine oocytes were also quantified. Results Nuclear maturation which is characterized by first polar body extrusion, and cytoplasmic maturation characterized by peripheral and cortical distribution of cortical granules and homogeneous mitochondrial distribution were significantly improved in the 50 μM EGCG-treated group compared with the control group. Adding 50 μM EGCG to the maturation medium significantly increased the cumulus cell expansion index and upregulated the mRNA levels of cumulus cell expansion-related genes (hyaluronan synthase 2, tumor necrosis factor alpha induced protein 6, pentraxin 3, and prostaglandin 2). Both the intracellular ROS level and the early apoptotic rate of matured oocytes were significantly decreased in the 50 μM EGCG group, and the total antioxidant ability was markedly enhanced. Additionally, both the cleavage and blastocyst rates were significantly higher in the 50 μM EGCG-treated oocytes after in vitro fertilization than in the control oocytes. The mRNA abundance of NRF2, SOD1, CAT, and GPX4 were significantly increased in the 50 μM EGCG-treated oocytes. Conclusion In conclusion, 50 μM EGCG can improve the bovine oocyte maturation, and the protective role of EGCG may be correlated with its antioxidative property

El patrimonio arqueológico del distrito Tambobamba - Apurímac y sus perspectivas de gestión

Se focaliza en el poblado de Tambobamba, en la cual analiza la situación actual del patrimonio arqueológico, evaluando el estado de protección del patrimonio arqueológico y los lineamientos existentes para implementar la gestión del Patrimonio Arqueológico del poblado de Tambobamba. Se debe indicar, además, que es el punto de partida para futuros trabajos que engloben a todo el distrito. Para el efecto se recurrió a la investigación documental y de campo, mediante el contacto con la realidad estudiada. Los resultados reflejan escasa participación de las autoridades locales en la gestión y manejo de los vestigios arqueológicos ubicados en su territorio; además de una escasa coordinación entre los diversos niveles de gobierno en lo que respecta a la problemática arqueológica. Por lo anterior se considera que es importante realizar un Plan de Gestión con objetivos a corto, mediano y largo plazo para las acciones de implementación, protección y conservación del patrimonio cultural y arqueológico de la zona; asimismo, promover la participación y la coordinación de todos los comprometidos con la protección del patrimonio, autoridades, instituciones del estado, organismos que promueven el turismo (agencias) y la población de la zona.Tesi

Facile Fluorescence "Turn on" Sensing of Lead Ions in Water via Carbon Nanodots Immobilized in Spherical Polyelectrolyte Brushes

Heavy metal detection has become very important for the protection of water resource. In this work, a novel controllable probe is presented for the sensitive detection of Pb2+ in aqueous solutions. The probe was synthesized via the immobilization of surface functionalized carbon dots (named as CAEA-Hs) into the shell of the spherical polyelectrolyte brushes (SPB). The fluorescence of CAEA-H was firstly "turned off" via electrostatic interaction induced quenching. Based on the aggregation induced emission enhancement (AIEE), the fluorescence of the immobilized CAEA-H could be specifically turned on via the aggregation of the SPB particles. This fluorescence "turn on" sensor could selectively detect Pb2+ among five different metal ions with a relatively wide detecting range (0-1.67 mM) and good linear relationship (R 2 = 0.9958). Moreover, the aggregating behavior and nano-structure of CAEA-H loaded SPB have been systematically analyzed via small angle X-ray scattering, turbidity titration, and Zeta-potential measurement. Based on a series of control experiments, we finally gain an insight into the sensing mechanism of this novel sensing probe. This contributed a proof of concept demonstration that sensitive and selective chemical detection can be achieved via a C-dot/SPB synergistic platform

Regular Patterns for Proteome-Wide Distribution of Protein Abundance across Species

A proteome of the bio-entity, including cell, tissue, organ, and organism, consists of proteins of diverse abundance. The principle that determines the abundance of different proteins in a proteome is of fundamental significance for an understanding of the building blocks of the bio-entity. Here, we report three regular patterns in the proteome-wide distribution of protein abundance across species such as human, mouse, fly, worm, yeast, and bacteria: in most cases, protein abundance is positively correlated with the protein's origination time or sequence conservation during evolution; it is negatively correlated with the protein's domain number and positively correlated with domain coverage in protein structure, and the correlations became stronger during the course of evolution; protein abundance can be further stratified by the function of the protein, whereby proteins that act on material conversion and transportation (mass category) are more abundant than those that act on information modulation (information category). Thus, protein abundance is intrinsically related to the protein's inherent characters of evolution, structure, and function