污水生物脱氮工程技术参数的探讨

对污水生物脱氮工程设计的污泥产率系数、DO、pH、系数0.47、好氧区(池)容积计算和反硝化效率等进行了探讨,以便于设计人员更好地理解<室外排水设计规范>(GB 50014-2006),不断推进我国污水处理技术的发展和标准的管理.     

Effect of corrosion potential on the corrosion fatigue crack growth behaviour of low-alloy steels in high-temperature water

The low-frequency corrosion fatigue (CF) crack growth behaviour of different low-alloy reactor pressure vessel steels was characterized under simulated boiling water reactor conditions by cyclic fatigue tests with pre-cracked fracture mechanics specimens. The experiments were performed in the temperature range of 240-288 °C with different loading parameters at different electrochemical corrosion potentials (ECPs). Modern high-temperature water loops, on-line crack growth monitoring (DCPD) and fractographical analysis by SEM were used to quantify the cracking response. In this paper the effect of ECP on the CF crack growth behaviour is discussed and compared with the crack growth model of General Electric (GE). The ECP mainly affected the transition from fast (‘high-sulphur’) to slow (‘low-sulphur’) CF crack growth, which appeared as critical frequencies ν_crit = f(ΔK, R, ECP) and ΔK-thresholds ΔK_EAC = f(ν, R, ECP) in the cycle-based form and as a critical air fatigue crack growth rate da/dt_Air,crit in the time-domain form. The critical crack growth rates, frequencies, and ΔK_EAC-thresholds were shifted to lower values with increasing ECP. The CF crack growth rates of all materials were conservatively covered by the ‘high-sulphur’ CF line of the GE-model for all investigated temperatures and frequencies. Under most system conditions, the model seems to reasonably well predict the experimentally observed parameter trends. Only under highly oxidizing conditions (ECP ? 0 mV_SHE) and slow strain rates/low loading frequencies the GE-model does not conservatively cover the experimentally gathered crack growth rate data. Based on the GE-model and the observed cracking behaviour a simple time-domain superposition-model could be used to develop improved reference CF crack growth curves for codes.     

Optimization of polyhydroxybutyrate (PHB) production by excess activated sludge and microbial community analysis

In this study, a high value-added and biodegradable thermoplastic, polyhydroxybutyrate (PHB), was produced by excess activated sludge. The effects of the nutritional condition, aeration mode, sodium acetate concentration and initial pH value on PHB accumulation in the activated sludge were investigated. The maximum PHB content and PHB yield of 67.0% (dry cell weight) and 0.740gCODgCOD(-1) (COD: chemical oxygen demand), respectively, were attained by the sludge in the presence of 6.0gL(-1) sodium acetate, with an initial pH value of 7.0 and intermittent aeration. The analysis of the polymerase chain reaction (PCR)-denaturing gradient-gel-electrophoresis (DGGE) sequencing indicated that the microbial community of the sludge was significantly different during the process of PHB accumulation. Three PHB-accumulating microorganisms, which were affiliated with the Thauera, Dechloromonas and Competibacter lineages, were found in the excess activated sludge under different operating conditions for PHB accumulation.     

真空除油干燥箱体内加热器位置优化

针对当前空调散热器工艺生产中常用除油工艺的局限性,本文提出了节能环保的真空干燥除油法,并就真空干燥除油箱体内温度场进行研究,利用FLUENT中DO模型仿真得到:在热源加热稳定的真空箱体内,分两层间隔布置的散热翅片的适宜摆放位置在箱体下半区域,该区域内温差较小,温差在7℃左右,其次对有效加热区范围进行了相关探讨,然后利用控制变量法建立起了热源总功率P与箱体体积V的理论模型,对除油箱设计具有一定的理论指导意义。     

DCS设计中DI／DO的有关问题探讨

对ＤＣＳ设计中ＤＩ／ＤＯ卡件的选用、ＤＩ／ＤＯ的隔离型式、接点型式及有关接线和供电等问题进行了较详细的描述，且发表了建设性见解。     

Fracture behavior of DO_3-ordered Fe-Al alloy with V addition

1　INTRODUCTIONTherehasbeenmoreandmoreresearchontheorderedironaluminidesbasedontheFe Alsysteminrecentyears .TheironaluminideFe3Aloccurswhenthecontentofaluminumisintherangeof 2 4 % 32 %(massfraction) .Ithastwoorderedstructures :DO3 orderedstructurewhichexistsbelowthecriticaltem peratureof 5 40℃andB2 orderedstructurebetween5 40and 76 0℃ .Theorderedironaluminideshaveexcellentoxidationresistance ,lowcost ,enrichmentinresourcesandsomeotheradvantages ,whichleadsthemtomanyengineeringapplic…     

底泥曝气改善城市河流水质的研究

以城市河流底泥为对象，研究了底泥曝气对水体修复的效果。研究表明：底泥曝气能强化水体溶解氧的恢复，有利于去除CODMn，并使其在较长时间内保持较低水平。底泥曝气对氨氮的去除效果一般，对总磷的去除效果最佳。底泥受扰动试验表明，底泥曝气能显著抑制CODMn氨氮和总磷的再次释放。     

以溶解氧浓度作为SBR法模糊控制参数

采用ＳＢＲ法处理石油化工废水,根据反应器内有机物降解与溶解氧浓度（ＤＯ０的相关性,提出了以ＤＯ作为ＳＢＲ法的模糊控制参数。通过大量试验,总结出反应实始阶段（８￣１０ｍｉｎ）溶解氧浓度不仅能够间接地反映进水有机物浓度（ＣＯＤ０,而且对整个反应过程都有重要影响。溶解氧的高低主要受曝气量大小控制,因此可根据初邕阶段溶解氧的浓度及变化情况预测进水有机物浓度,进而实现对曝气量的模糊控制。同时,还发现当有机物     

Experimental simulation of biodegradation in rivers: Oxygen, organic matter and biomass concentration changes

Dissolved oxygen (DO) and biochemical oxygen demand (BOD) concentration changes after an organic matter discharge into a river have been studied in the absence of oxygen transfer. According to these laboratory experiments, biodegradation of various organic compounds (glucose, glutamic acid, starch, ovalbumin and ethanol) in Seine river samples incubated at 15 30°C follow a biphasic behaviour. During a lag-phase of 10–20 h, DO decreases linearly (0.12 ppm h⁻¹ at 20°C), whereas BOD is constant. During a subsequent aerobic exponential phase, DO and BOD uptake are proportional and increase exponentially with time (0.13 h⁻¹ at 20°C). Using cell ATP as biomass indicator, the latter phase was shown to correspond to a cell division step. A kinetic model was developed for stimulating DO and BOD concentration changes after a waste water discharge at temperatures ranging between 15 and 30°C.     

快淬Fe81Ga19合金薄带的相结构和磁致伸缩

采用熔体快淬法制备Fe81Ga19合金薄带,研究薄带试样的相结构和磁致伸缩性能.XRD和M-TG结果表明,快淬态Fe81Ga19合金基体为Fe(Ga)无序固溶体相,并有微量非对称结构的DO3相析出,且薄带厚度方向[100]择优取向.当测量磁场垂直带面时,薄带试样沿带长方向的饱和磁致伸缩达-1830×10-6.Fe81Ga19合金薄带的巨磁致伸缩与其大的形状各向异性、熔体快淬时合金内部形成的非对称结构的DO3相及薄带厚度方向[100]择优取向相关.