Effect of hydrogen in advanced high strength steel materials

The effect of hydrogen in AHSS material (automobile and structural component) was discussed. Dual Phase steels were highly susceptible to hydrogen-related failure when working on hydrogen environment. The influence of hydrogen on TRIP steel was seen during fractographic examination where the brittle transgranular fracture was presented. TWIP steels results were inconsistent. The mechanisms which were responsible for crack growth are discussed. LIST and SSRT testing were performed for mechanical properties evaluation and SEM and TEM were used for microstructural examination of fractured samples. Simultaneous preventing methods to reduce hydrogen embrittlement such as coating, alloying and providing diffusion layer were discussed.     

借助图案填充快速求算AutoCAD图形面积的方法探讨——应用AutoCAD求算闭合地块面积的方法探讨（二）

面积是各级土地管理部门和规划部门经常用到的土地的重要信息，本文主要探讨借助HATCH命令填充图案求算闭合地块面积的方法。     

从副产焦油中回收TDI装置的稳定运行

针对焦油处理装置在TDI焦油回收运行中存在的气液固三相处理装置跳车、进料管堵塞、气相管堵塞等问题,进行了相应的技术改造:取消进料压降主要集中的FV01控制阀,将闪蒸阀换为可远传控制的调节阀;延缓开停车时间,保证连续稳定进料;控制系统真空度2.5kPa(A)￣3.0kPa(A);加强对设备的保养和维护。改造后,提高了焦油回收装置的运转周期,降低了生产能耗。     

Hydrogen embrittlement in different materials: A review

Hydrogen embrittlement (HE) is a widely known phenomenon in high strength materials. HE is responsible for subcritical crack growth in material, fracture initiation and catastrophic failure with subsequent loss in mechanical properties such as ductility, toughness and strength. This hydrogen is induced in the material during electrochemical reaction and high-pressure gaseous hydrogen environment. LIST, SSRT and TDS techniques are performed to know the effect in mechanical properties and amount of hydrogen available in the material. For microstructure examination SEM, FESEM and TEM are performed to know the effect of hydrogen in the internal crystal structure. Also, various mechanisms which are responsible for crack growth and final fracture are discussed. This paper deals with HE definition, mechanisms which causes HE, subcritical crack growth, the concentration of hydrogen measurement and prevention activities are discussed which act as a barrier for hydrogen diffusion.     

The influence of applied stress rate on the stress corrosion cracking of 4340 and 3.5NiCrMoV steels in distilled water at 30 °C

Linearly Increasing Stress Tests conducted in 30 °C aerated distilled water using as-quenched 4340 and 3.5NiCrMoV turbine rotor steels indicated that stress corrosion cracking occurred at all applied stress rates for 4340 steel, whilst only at applied stress rates less than or equal to 0.002 MPa s⁻¹ for the turbine rotor steel. The crack velocity increased with increasing applied stress rate for both steels with the maximum crack velocity for 4340 steel corresponded to v_II in fracture mechanics tests in room temperature water. The fracture surface morphology was mixed mode consisting of intergranular and transgranular fracture regions.     

Removal of carbon and nutrients from domestic wastewater using a low investment, integrated treatment concept

An integrated chemical-physical-biological treatment concept for the low-cost treatment of domestic wastewater is proposed. Domestic wastewater was subjected to a chemically enhanced primary treatment (CEPT), followed by treatment in an upflow anaerobic sludge blanket (UASB) reactor. In addition, a regenerable zeolite was used to remove NH4+, either after CEPT pretreatment or after biological treatment in the UASB reactor. The CEPT pretreatment consisted of the addition of a coagulant (FeCl3) and an anionic organic flocculant and removed on average 73% of the total chemical oxygen demand (COD(t)), 85% of the total suspended solids, and 80% of PO4(3-) present in the wastewater. The UASB system, which consequently received a low COD(t) input of approximately 140 mg/L, was operated using a volumetric loading rate of 0.4 g COD(t)/L. d (hydraulic retention time [HRT]=10 h) and 0.7 g COD(t)/L. d (HRT=5 h). For these conditions, the system removed about 55% of the COD(t) in its influent, thus producing an effluent with a low COD(t) of approximately 50 mg/L. The zeolite, when applied in batch mode before the UASB reactor, removed approximately 45% of the NH4+, whereas its application as a post-treatment cartridge resulted in almost 100% NH4+ removal. The simple design and relatively low operating costs, due to low costs of added chemicals and low energy input (estimated at Euro 0.07-0.1 per m3 wastewater treated), combined with excellent treatment performance, means that this system can be used as a novel domestic wastewater treatment system for developing countries. Therefore, the system is called a Low Investment Sewage Treatment (LIST) system.     

应用AutoCAD求算闭合地块面积的方法探讨

面积是各级土地管理部门和规划部门经常用到的土地的重要信息,除了专业土地软件外直接应用AutoCAD软件也可以非常方便的求算闭合地块的面积。     

大数据时代图书信息服务的创新探讨

大数据时代的到来为图书馆信息服务的创新型研究提供了可能性,为深入探讨其发展潜力和趋势,本文就大数据时代信息服务的基本特点进行阐述,并提出其现阶段面临的挑战,并提出未来发展的相应措施。     

RIFF文件浅析

在Windows环境下，大部分的多媒体文件都是依循着一种文件结构来存放信息的。这个结构为“资源互换文件格式(Resources Interchange File Format)，简称RIFF。例如：声音的WAV文件、视频的AVI文件等等均是由此结构衍生出来的。RIFF可以看做是一种树状结构，其基本组成单元为CHUNK、LIST。犹如树的节点、叶子。