Simulation and Analysis of Cascading Faults in Integrated Heat and Electricity Systems Considering Degradation Characteristics

Cascading faults have been identified as the primary cause of multiple power outages in recent years.With the emergence of integrated energy systems(IES),the conventional approach to analyzing power grid cascading faults is no longer appropriate.A cascading fault analysis method considering multi-energy coupling characteristics is of vital importance.In this study,an innovative analysis method for cascading faults in integrated heat and electricity systems(IHES)is proposed.It considers the degradation characteristics of transmission and energy supply com-ponents in the system to address the impact of component aging on cascading faults.Firstly,degradation models for the current carrying capacity of transmission lines,the water carrying capacity and insulation performance of thermal pipelines,as well as the performance of energy supply equipment during aging,are developed.Secondly,a simulation process for cascading faults in the IHES is proposed.It utilizes an overload-dominated development model to predict the propagation path of cascading faults while also considering network islanding,electric-heating rescheduling,and load shedding.The propagation of cascading faults is reflected in the form of fault chains.Finally,the results of cascading faults under different aging levels are analyzed through numerical examples,thereby verifying the effectiveness and rationality of the proposed model and method.

Isolation and Identification of Triazophos-degrading Bacillus subtilis str. C-Y106 and Its Degradation Characteristics

[Objective] The aim was to isolate the triazophos-degrading strain and study its degradation characteristics. [Method] A triazophos-degrading bacterium strain C-Y106 was isolated from sludge in an aeration tank of triazophos manufacture. Then the strain C-Y106 was identified according to the morphology,physiological and biochemical characteristics,and 16S rRNA sequence analysis. The effect of medium with different nutrients on triazophos-degrading rate by C-Y106 was studied. [Result] The strain C-Y106 was identified as Bacillus subtilis. The strain C-Y106 could grow in the mineral salt medium with 40 mg/L of triazophos as the sole sources of carbon,Nitrogen and Phosphorus. The triazophos-degrading rate was the highest as 76.8% in the mineral salt medium with 40 mg/L of triazophos as the sole source of Phosphorus,after being incubated at 31 ℃,pH 8.0 and 150 r/min for 60 h. [Conclusion] The research had provided theoretical basis for the identification and purification of enzymes for triazophos degradation.

Degradation Characteristics and Community Structure of a Hydrocarbon Degrading Bacterial Consortium

A hydrocarbon degrading bacterial consortium KO5-2 was isolated from oil-contaminated soil of Karamay in Xinjiang, China, which could remove 56.9% of 10 g/L total petroleum hydrocarbons(TPH) at 30 ℃ after 7 days of incubation, and could also remove 100% of fluorene, 98.93% of phenanthrene and 65.73% of pyrene within 3, 7 and 9 days, respectively. Twelve strains from six different genera were isolated from KO5-2 and only eight ones were able to utilize the TPH. The denaturing gradient gel electrophoresis(DGGE) was used to investigate the microbial community shifts in five different carbon sources(including TPH, saturated hydrocarbons, fluorene, phenanthrene and pyrene). The test results indicated that the community compositions of KO5-2 in carbon sources of TPH and saturated hydrocarbons, respectively, were roughly the same, while they were distinctive in the three different carbon sources of PAHs. Rhodococcus sp. and Pseudomonas sp. could survive in the five kinds of carbon sources. Bacillus sp., Sphingomonas sp. and Ochrobactrum sp. likely played key roles in the degradation of saturated hydrocarbons, PAHs and phenanthrene, respectively. This study showed that specific bacterial phylotypes were associated with different contaminants and complex interactions between bacterial species, and the medium conditions influenced the biodegradation capacity of the microbial communities involved in bioremediation processes.

Study on Isolation and Degradation Characteristics of an Aniline-degrading Strain

[Objective] The research aimed to screen out an efficient aniline-degrading strain and study its degradation characteristics. [Method] By domesticated enrichment culture, an efficient aniline-degrading strain named as DA-K was isolated from activated sludge sample collected from a chemical plant in Henan. DA-K could use aniline as the sole carbon and nitrogen sources. The strain was carried out physiological and biochemi- cal identification, and its biological degradation characteristics were studied. [ Result] DA-K strain was G - and red-shaped, and its colony color was off-white. It was initially determined as Acinetobacter sp. By measuring, the optimum growth temperature and pH for DA-K were respectively 30 ~C and 6.0. DA-K strain could grow well in inorganic salt medium with aniline of 2 500 mg/L. After shaking for 96 h under the conditions of pH 6.0, 30 ℃, 180 r/min and 1 000 mg/L of aniline, the degradation rate of the aniline by DA-K could reach nearly 80%. [ Conclusion] The DA-K strain had a higher aniline degradation efficiency and actual treatment capability of the aniline wastewater, which laid foundation for establishing gene engineerincl strain.

Preparation and Degradation Characteristics of Poly(d,1-laetide) Composite Films

PDLLA/CHI/β-TCP/NGF composite films were prepared by a solvent evaporation method. The degradation characteristics of the poly （d, l-lactide） composite films were studied in vitro and in vivo. The acidity produced by poly （d, l-lactide） materials was not obvious. Adding chitosan and β-TCP can relieve the acidity problem and improve strength performance of films. The NGF has influences on the degradation characteristics of films. It is verified that PDLLA/CHI/β-TCP/NGF composite films prepared by solvent evaporation method have excellent degradation characteristics. It can be used as a perfect biomaterial for repairing nerve injuries.

Characteristics of change of humic substance in soil in degraded grass lands

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Degradation analysis of A^2/O combined with AgNO3 + K2FeO4 on coking wastewater

In this work, a coking wastewater was selected and a biochemical Az/O treatment device for fractional degradation was designed and employed. After each stage of the treatment, the products were analyzed through gas chromatography-mass spectroscopy （GC-MS） to determine their composition. Finally, AgNO3 ＋ K2FeO4 was used as an advanced deep catalytic oxidation treatment. It was concluded from the analysis that cyclic organics could be degraded and the chemical oxygen demand （COD） was controlled within 50 mg. L-1, in line with the target value, Meanwhile, the spectra obtained from the GC-MS were in accordance with the conclusions reached based on the COD. The research results showed that all hard-degradable organics in coking wastewater could be eliminated through the A2/O bio-membrane treatment and the advanced treatment of making use of K2FeO4 as an oxidant and Ag＋ as a catalyst, the catalytic efficiency with Ag＋ as a catalyst of K2FeO4 was very high. Ag＋ could evidently improve the oxidation capacity of K2FeO4 to wastewater in its short stability time, and this is an important innovation.

Isolation of two atrazine-degrading strains and their degradation characteristics

To investigate the optimum growth conditions and screen atrazine-degrading strains,two atrazine-degrading strains named Z9 and Z42 were isolated from black earth in a cold area with a long-term application of atrazine by standard enrichment techniques.Z9 utilizes atrazine as both the nitrogen and carbon source whereas Z42 utilizes atrazine as the sole nitrogen source to grow.The atrazine degradation rates of the two strains reached 77.7%and 65.6%,respectively after 14 days culture in a liquid medium with an atrazine concentration of 100 mg/L.Z9 and Z42 were identified as Microbacterium sp.and Arthrobacter sp.The optimum inoculation amount and rotation speed for Z9 and Z42 to grow and degrade atrazine are 3%and 120 r/min respectively.

Degradation of malachite green dye by Tenacibaculum sp. HMG1isolated from Pacific deep-sea sediments

A deep-sea bacterium from the Pacific Ocean identified as Tenacibaculum sp. HMG1 was found to have strong malachite green（MG） degradation activity. The MG tolerance and decolorizing activities of strain HMG1 were confirmed by bacterial growth and high-performance liquid chromatography（HPLC） analyses. Strain HMG1 was capable of removing 98.8% of the MG in cultures within 12 h and was able to grow vigorously at 20 mg/L MG. A peroxidase gene detected in the genome of strain HMG1 was found to be involved in the MG biodegradation process. The corresponding recombinant peroxidase（r POD） demonstrated high degradative activity at 1 000 mg/L MG. Based on the common candidate intermediates, strain HMG1 was inferred to have one primary MG degradation pathway containing r POD. In addition, five other candidate intermediates of the r POD-MG degradative process were detected. The optimal conditions for MG degradation were determined and showed that strain HMG1 and the r POD enzyme could maintain high bioactivity at a low temperature（20℃）, variable p H values（6.0–9.0）, higher salinities（100 mmol/L） and other factors, such as multiple metal ions, H2O2 and EDTA.MG-tolerant strain Tenacibaculum sp. HMG1 and its peroxidase have prospective applications as environmental amendments for MG degradation during coastal remediation.

Degradation Characteristic of PDLLA/HA Composite Fiber in vitro

The in vitro degradation characteristic of the poly D, L-lactic acid （ PDLIA ）/ hydroxyapatite （ HA ） compound were investigated. The compoundfibers were immersed in static phosphate buffer at 37℃ to degrade for 22 weeks. The changes in pH value of the buffer solution, the mechanical strength and morphological of inside and outside of composite fibers with degrurlation characteristic were observed. Results show that pH value of the buffer solution stabilized to aboat 7.0 before 12 weeks, however after 20 weeks that pH value quick declined. After 7 weeks that composite fibers of mechanical strength cannot mensuration. SEM observation revealed ttua bimodal degradation occurred in composite fibers.

Low Temperature Reduction Degradation Characteristics of Sinter,Pellet and Lump Ore

The reduction degradation characteristics of typical sinter, pellet and lump ore were tested with the reducing gas conditions simulating two kinds of irowmaking processes. The results show that, in the same condition of gas composition and temperature, the reduction degradation degree （RDI〈3.15mm） of sinter is high, RDI〈3.15mm of lump ore is low and RDI〈3.15 mm of pellet is in the middle level. With two kinds of gas composition simulating different iron-making processes, the reduction degradation indices （RDI） of three kinds of iron ores all present the tenden- cy of ＂inverted V-shape＂ in the temperature range from 450 to 650℃, and the RDI reach the maximum value at 550℃. The reduction degradation degrees of iron ores are extended when mixing the gas with hydrogen to increase the re duction potential, and the influence extent is discrepant for different iron ores. Colligating the increase amplitude of grains in small size fraction, the influence of reducing gas on lump ore is the greatest, the influence on sinter is the second, and the sensitivity of pellet on the reducing gas properties change is relatively small. As for the degradation form, lump ore and sinter both present the degradation ,of cracking, and the distribution of small grains generated from the cracking is in the range from 03 5 to 6. 3 mm uniformly. The lump ore presents surface cracking, while sin- ter presents integral cracking. The pellet presents the degradation of surface stripping, and the proportion of grains smaller than 0.5 mm is the highest, which is up to 90% in the grains smaller than 3.15 mm.

Erosion degradation characteristics of a linear electro-hydrostatic actuator under a high-frequency turbulent flow field

The paper proposes a performance degradation analysis model based on dynamic erosion wear for a novel Linear Electro-Hydrostatic Actuator（LEHA）. Rather than the traditional statistical methods based on degradation data, the method proposed in this paper firstly analyzes the dominant progressive failure mode of the LEHA based on the working principle and working conditions of the LEHA. The Computational Fluid Dynamics（CFD） method, combining the turbulent theory and the micro erosion principle, is used to establish an erosion model of the rectification mechanism. The erosion rates for different port openings, under a time-varying flow field, are obtained. The piecewise linearization method is applied to update the concentration of contaminated particles within the LEHA, in order to gain insight into the erosion degradation process at various stages of degradation. The main contribution of the proposed model is the application of the dynamic concentration of contamination particles in erosion analysis of Electro-Hydraulic Servo Valves（EHSVs）, throttle valves, spool valves, and needle valves. The effects of system parameters and working conditions on component wear are analyzed by simulations. The results of the proposed model match the expected degradation process.