Nitrogen Composition and Feeding Value of Annual Forages as Affected by Nitrogen Fertilization and Defoliation Frequency.

Initially, various solvents were tested for their efficacy in isolating soluble nitrogen (SN) from annual ryegrass and berseem clover. Plant nitrogen (PN) solubilities were similar in.5 M NaCl, autoclaved rumen fluid, borate phosphate buffer and Burroughs\u27 solution. The mean PN solubilities across forages ranged from 12% for.1 M acetic acid to 45% for.2% NaOH. At 4\sp\circC, 15% TCA precipitated the most soluble plant protein nitrogen (SPPN). Nitrogen (N) yield, concentrations of PN, SN, SPPN and soluble nonprotein nitrogen (SNPN) increased linearly as N fertilization (NF) increased from 0 to 335 kg N/ha. Decreasing defoliation interval (DI) from 6- to 2-wk decreased PN yield, and linearly increased concentrations PN, SN, SPPN and SNPN. However, NF and DI did not affect the proportions of SN, SPPN and SNPN in PN pools and the ruminal degradabilities of PN and dry matter (DM) as measured in nylon bags. Solubilities of PN and ruminal degradabilities of PN and DM declined with advancing growing season. A lamb metabolism study was conducted to determine the ruminal degradability and metabolic usage of ryegrass N as affected by NF (0 or 224 kg N/ha) and DI (2- or 6-wk). Abomasal flows of total N and NH\sb3 N were higher and abomasal flow of ADF\sb-N was lower in growing lambs fed fertilized vs unfertilized ryegrass. Similarly, abomasal flows of total N and NH\sb3 N were higher in the lambs fed 2-wk vs 6-wk regrowth ryegrass. Abomasal flow of microbial N was not affected by treatments. However, abomasal non-microbial N flow tended to be higher in lambs fed fertilized vs unfertilized or 2-wk vs 6-wk regrowth ryegrass. Ruminal and total tract digestibilities of DM, and NDF and ADF were higher for fertilized than for unfertilized ryegrass. When compared to lambs fed unfertilized ryegrass, those fed fertilized ryegrass had higher BUN (21.4 vs 13.3 mg/dl) and rumen NH\sb3 N (21.4 vs 13.4 mg/dl), and tended to have higher ruminal free amino acids and pH, and retained more N. Lambs fed 2-wk DI ryegrass tended to retain more N than those fed 6-wk DI ryegrass

Multi-stage sizing approach for development of utility-scale BESS considering dynamic growth of distributed photovoltaic connection

The battery energy storage system (BESS) is regarded as one of the most promising address operational challenges caused by distributed generations. This paper proposes a novel multi-stage sizing model for utility-scale BESS, to optimize the BESS development strategies for distribution networks with increasing penetration levels and growth patterns of dispersed photovoltaic (PV) panels. Particularly, an integrated model is established in order to accommodate dispersed PVs in short-term operation scale while facilitating appropriate profits in long-term planning scale. Clusterwise reduction is adopted to extract the most representative operating scenarios with PVs and BESS integration, which is able to decrease the computing complexity caused by scenario redundancy. The numerical studies on IEEE 69-bus distribution system verify the feasibility of the proposed multi-stage sizing approach for the utility-scale BESS.</p

Reactive coordinated optimal operation of distributed wind generation

Large-scale distributed wind generation (DWG) integration brings new challenges to the optimal operation of the distribution network. The reactive supports from wind turbines (WTs) and reactive power resources can improve both the operation economy and renewable energy consumption. In this paper, a multi-period reactive coordinated optimal operation model for DWG in the distribution network is established. The active-reactive power coordination characteristics of two typical types of WTs are considered and the operating strategy of reactive power resources is integrated in the model. The second-order cone programming (SOCP) is developed to transform the original nonlinear power flow model into a linear and convex model, which would significantly improve the power flow calculation efficiency for DWG penetrated distribution network. The simulation results show that the integration of reactive power resources can further promote the consumption of DWG and improve the operating profits of the distribution network

Buddhist Vegetarian Restaurants and the Changing Meanings of Meat in Urban China

This article charts the changing meanings of meat in contemporary urban China and explores the role played by Buddhist vegetarian restaurants in shaping these changes. In Kunming, meat has long been a sign of prosperity and status. Its accessibility marked the successes of the economic reforms. Yet Kunmingers were increasingly concerned about excessive meat consumption and about the safety and quality of the meat supply. Buddhist vegetarian restaurants provided spaces where people could share meat-free meals and discuss and develop their concerns about meat-eating. While similar to and influenced by secular, Western vegetarianisms, the central role of Buddhism was reflected in discourses on karmic retribution for taking life and in a non-confrontational approach that sought to accommodate these discourses with the importance of meat in Chinese social life. Finally, the vegetarian restaurants spoke to middle-class projects of self-cultivation, and by doing so potentially challenged associations between meat-eating and social status

Preparation and Properties of Viscose Rayon/O-carboxymethyl Chitosan Antibacterial Fibers

ABSTRACT Antimicrobial viscose rayon/O-carboxymethyl chitosan fibers (VCMFs) were manufactured by spinning the mixture of O-carboxymethyl chitosan (O-CMCS) xanthate and cellulose xanthate via the viscose process. The structure, morphology and mechanical properties were investigated by infrared, scanning electron microscopy, transmission electron microscope and tensile test. The results show that the blend fibers of cellulose and O-CMCS were satisfactorily prepared and the two polymers were mixed homogeneously. VCMFs display striation along the fiber similar to those of viscose rayon fibers, and their mechanical properties are close to that of viscose rayon. With O-CMCS blended, VCMFs showed good moisture absorption and antibacterial activity against E.coli

Coordinating voltage regulation for an AC–DC hybrid distribution network with multiple SSTs

The increasing penetration of renewable generation and large implementation of the DC loads are challenges that stress the current distribution systems by causing uncertain voltage variations. The AC−DC hybrid distribution network is seen as an innovative solution to address the problem of accommodating highly dispersed sustainable energy. Specifically, the solid-state transformer (SST), which is capable of enhancing power-quality performance and controllability of the power distribution, has attracted increasing focus in this decade as a promising advanced converter. It is of great interest to investigate how to operate the multiple SSTs with different modes in a coordinated manner to optimise the distribution network performance. This paper formulates the coordinated operation model for multiple SSTs to enable fast voltage regulation for the hybrid active distribution network equipped with large-scale penetration of invertor-based solar power and DC load. A hybrid optimal power flow describing the controlling modes of SSTs and operating interaction between AC−DC subsystems is proposed in this paper. The case studies on a modified IEEE 33-AC−DC hybrid power distribution system show that the voltage profile can be optimised by using the flexible controlling resource of SSTs, facilitating the timely performance adjustment in the presence of fast fluctuating distributed generator's output

Compact and Circular Polarized RFID Antenna for Portable Terminal Applications

A novel compact and circular polarized antenna is proposed which can be easily fabricated and embedded into RFID readers. Circular polarization characteristic of the proposed antenna is achieved by introducing a crossed branch. The modified meandering line structure gives the antenna compactness characteristic. A prototype is fabricated and measured. The results show that this circular polarized antenna with compact dimension can cover the Chinese RFID operating band from 920 MHz to 925 MHz, which make's the antenna suitable for handheld terminal application of RFID readers

Electric vehicles in smart grid: a survey on charging load modelling

Electric vehicles (EVs) have been rapidly developed during the last few years due to the low-carbon industry and smart grid initiatives. Meanwhile, the impact of large-scale EVs' integration on the reliability and safety of power grids is becoming increasingly prominent. To address and solve these problems, challenges on EV charging control have been presented. Besides, the EV charging load modelling with improved accuracy and rationality is required. To investigate the influencing factors of EV charging load, this survey summarises the existing EV charging load modelling methods. In addition, a new research framework for a scale EV evolution model of charging load is proposed, with an emphasis on reducing the deficiencies of the existing research in dealing with the EV scale development. Moreover, the future research prospect of EV charging load modelling on power system planning, operation, and market design has also been discussed