Influence of Mg and Ti on the microstructure and electrochemical performance of aluminum alloy sacrificial anodes

The experiments focused on the influence of magnesium and titanium as additional alloying elements on the microstructure and electro-chemical behavior of Al-Zn-In sacrificial anodes. The electrochemical behavior of the aluminum sacrificial anode with 3 wt.% sodium chloride solution was studied by electrochemical impedance spectroscopy (EIS) tests. It was found that a microstructure with few precipitates and refined grains could be achieved by adding 1 wt.% Mg and 0.05 wt.% Ti to the Al-Zn-In alloy,resulting in the improved current capacity and efficiency of the alloy. The equivalent circuit based on the EIS experimental data revealed less corrosion and lower adsorbed corrosion production on the surface of the aluminum alloy with a combination of 1 wt.% Mg and 0.05 wt.% Ti,which suggested that the corrosion behavior seemed to be strongly related to the presence of precipitate particles in the aluminum alloy,and moderate amounts of precipitate particles could be beneficial to the electrochemical performance of the aluminum alloy sacrificial anode.

Effect of Oxide Inclusions on Electrochemical Properties of Aluminium Sacrificial Anodes

Oxide films are incorporated into melts by an entrainment process, and are expected to be present in most metals, but particularly cast Al alloys. The oxides are necessarily present as folded-over double films （bifilms） that are effectively cracks. Their effect on the electrochemical behaviour of cast Al-SZn-0.021n sacrificial anodes was studied in 3 wt pct sodium chloride solution using the NACE efficiency evaluation. Three methods were employed to entrain progressive amounts of oxide in the alloy, including the addition of Al-Zn-ln maching chips to the charge, increasing the pouring height, and agitating the melt. The introduction of oxide bifilms in the cast alloy resulted in the deterioration of the electrochemical properties of the sacrificial anodes, such as current capacity and anode efficiency, and introduced increasing variability in these properties. The results suggest that corrosion behaviour is strongly related to the presence of bifilms suspended in the liquid alloy because bifilms provide crack paths allowing the corrodant to penetrate deeply into the metal matrix, and simultaneously provide localized galvanic cells because of the precipitation of Fe rich intermetallic compounds on their outer surfaces.

Effect of Sacrificial Anode Protection for Steel Pipe Piles at Dandong Port

The sacrificial anode protection system for the steel pipe piles of the 3rd berth of Dandong; wharf at Dandong port has operated for eight years. In this paper, the program design and the protection effect of the sacrificial anode protection system are presented. The results of various inspections show that the piles are protected very satisfactorily.

Effects of Zinc Addition on the Performance of Aluminium as Sacrificial Anode in Seawater

In this work, the effect of zinc addition on the performance of aluminium-based sacrificial anode in seawater was investigated. The parameters used in assessing the performance of the cast anodes are anodic efficiency, protection efficiency and polarized potential. The percentages of Zn in the anodes were varied from 1 to 8%Zn. The alloys produced were tested as sacrificial anode for the protection of mild steel in seawater at room temperature. Current efficiency as high as 86.69% was achieved at 6%Zn in the alloys. The polarized potential obtained for the couples(steel/Al based alloys) are as given in the pourbaix diagrams with the steel lying within the immunity region/cathodic region ( S-0.5V SHE) and the sacrificial anodes within the anodic region. The protection offered by the sacrificial anodes to the steel after the 7th and 8th week were measured. Protection efficiency values as high as 99.26% and 99.13% were achieved after the 7th and 8th with Al-6%Zn. The microstructure showed the intermetallic structures of β-phase which breakdown the alumina passive film and thus enhancing the anode efficiency.

Effects of strain-induced melt activation treatment on the microstructure and properties of Zn sacrificial anodes

The microstructural properties and electrochemical performance of zinc(Zn)sacrificial anodes during strain-induced melt activation(SIMA)were investigated in this study.The samples were subjected to a compressive ratio of 20%-50% at various temperatures(425-435℃)and durations(5-30 min).Short-term electrochemical tests(anode tests)based on DNV-RP-B401 and potentiodynamic polarization tests were performed in 3.5wt%NaCl solution to evaluate the electrochemical efficiency and corrosion behavior of the samples,respectively.The electrochemical test results for the optimum sample confirmed that the corrosion current density declined by 90% and the anode efficiency slightly decreased relative to that of the raw sample.Energy-dispersive X-ray spectroscopy,scanning electron microscopy,metallographic images,and microhardness profiles showed the accumulation of alloying elements on the boundary and the conversion of uniform corrosion into localized corrosion,hence the decrease of the Zn sacrificial anode’s efficiency after the SIMA process.

Sacrificial microgel‑laden bioink‑enabled 3D bioprinting of mesoscale pore networks

Three-dimensional(3D)bioprinting is a powerful approach that enables the fabrication of 3D tissue constructs that retain complex biological functions.However,the dense hydrogel networks that form after the gelation of bioinks often restrict the migration and proliferation of encapsulated cells.Herein,a sacrificial microgel-laden bioink strategy was designed for directly bioprinting constructs with mesoscale pore networks(MPNs)for enhancing nutrient delivery and cell growth.The sacrificial microgel-laden bioink,which contains cell/gelatin methacryloyl(GelMA)mixture and gelled gelatin microgel,is first thermo-crosslinked to fabricate temporary predesigned cell-laden constructs by extrusion bioprinting onto a cold platform.Then,the construct is permanently stabilized through photo-crosslinking of GelMA.The MPNs inside the printed constructs are formed after subsequent dissolution of the gelatin microgel.These MPNs allowed for effective oxygen/nutrient diffusion,facilitating the generation of bioactive tissues.Specifically,osteoblast and human umbilical vein endothelial cells encapsulated in the bioprinted large-scale constructs(≥1 cm)with MPNs showed enhanced bioactivity during culture.The 3D bioprinting strategy based on the sacrificial microgel-laden bioink provided a facile method to facilitate formation of complex tissue constructs with MPNs and set a foundation for future optimization of MPN-based tissue constructs with applications in diverse areas of tissue engineering.

Seismic response of rocking isolated railway bridge piers with sacrificial components

In this study, sacrificial components were incorporated into self-centering railway bridge piers to improve the lateral stiffness. The seismic response of this new detail was investigated. First, the method to compute the initial uplift moment of the self-centering pier is given. In addition, shaking table tests were conducted on a free-rocking pier without sacrificial components, which was used to validate a two-spring numerical model. Good agreement was obtained between the numerical results and experimental data. Furthermore, the validated model was employed to investigate the influence of sacrificial components on the seismic response of rocking piers. For this purpose, two models were developed, with and without sacrificial components. Nonlinear response history analysis was then performed on both models under three historical motions. The results showed that compared to the one without sacrificial components, the rocking pier with sacrificial components has comparable displacement at the top of the pier, and maximum uplift moment at high amplitude motion. Therefore, incorporating sacrificial components into the rocking pier can increase the lateral stiffness at service load and low amplitude frequent earthquakes but can produce comparable response at high seismic excitation. These results provide support for performance-based seismic design of self-centering rocking piers.

A novel method for sacrificial layer release in MEMS devices fabrication

During the forming process of the free-standing structure or the functional cavity when releasing the high aspect ratio sacrificial layer, such structures tend to stick to the substrate due to capillary force. This paper describes the application of pull-in length conception as design rules to a novel ＇dimpled＇ method in releasing sacrificial layer. Based on the conception of pull-in length in adhering Phenomenon, the fabrication and releasing sacrificial layer methods using micro bumps based on the silicon substrate were presented. According to the thermal isolation performances of one kind of micro electromechanical system device thermal shear stress sensor, the sacrificial layers were validated to be successfully released.

Direct Process to Prepare Crystallized Freestanding Membranes of Hydroxyapatite Using Sacrificial Layer of Barium-Compounds

Freestanding membrane (FSM) of hydroxyapatite (HA) is a thin sheet of pure HA without any supporting substrates. Our original preparation process of FSM of HA had three steps: The first was the deposition of HA layer on sacrificial layer of solvent-soluble materials, the second was separation of FSM of HA by means of dissolution of sacrificial layer, and the third was post-annealing to crystallize FSM of HA. To date, the post-annealing process was a serious bottleneck of productivity owing to its too long time. In this short report, we proposed a novel sacrificial layer, heatproof and water-soluble Ba-compound, which makes the direct deposition of crystallized HA possible due to its heatproof property because the problem on the original process was that the previous sacrificial layers have no heatproof property and HA layer should be deposited as amorphous. We can deposit the Ba-compound sacrificial layer only in 1 hour followed with the direct deposition of crystallized HA layer, substituting the 20 hours of post-annealing. The FSM of HA was separated successfully from the substrate by means of dissolution of Ba-compound with water. Our novel process can shrink the process time by 19 hours.

Environmental Impact Assessment of Sacrificial Anode Method in Taiwan Strait

Taiwan Strait is one of the potential wind farm in the world. Cooperate with the development of national policies, thousands of offshore wind turbines will be installed in Taiwan Strait. In order to enable offshore wind turbine foundation to be erected in the ocean for a long time, the offshore structure facilities are protected by sacrificial anode or impressed current of today. This study utilized the MIKE21 numerical model, combined with ocean parameters such as sea waves and tidal current to simulate the change of the diffusion concentration and diffusion range of the materials released by the aluminum sacrificial anode blocks by the Changhua offshore wind farm located on Taiwan Strait in winter and summer, thus to evaluate the impact on the marine environment.

Simulation of the Cracking and Ablation Behavior of Ferrosiliceous and Siliceous Nuclear Sacrificial Concretes

We investigated the simulation of the cracking and ablation behavior of ferro-siliceous and siliceous nuclear sacrificial concretes. To this end, four type of sacrificial concretes were fabricated, i e, the ferro-siliceous（F） and siliceous（S） plain concretes, and the polypropylene fiber reinforced concretes of the above two（FF, SF）. The cracking and ablation behaviors of the sacrificial concretes were investigated by simulation tests, and the simulated elevated temperature was obtained by means of thermite powder. The number and the width of the cracks were compared and the pore size distribution of sacrificial concretes was measured. In addition, the interface and chemical composition of melt at different positions were analyzed, and the ablation depth of the sacrificial concrete crucibles was also measured. It was found that the siliceous concrete shows to be more prone to cracking than the ferro-siliceous concrete due to the higher content of fly ash and lower water to binder ratio; though the ablation depth of siliceous concrete is found to be slightly larger, no clear difference can be detected for the basemat ablation rate.

A New Self-assembly Metal CMG Discriminator by Multi-exposure LiGA Like Process and Sacrificial Layer Process

The counter-meshing gears (CMG) discriminator is a mechanically coded lock, which is used to prevent the occurrence of High Consequence Events. This paper advanced a new kind of self-assembly metal CMG discriminator based on multi-exposure LiGA like process and sacrificial layer process. The new CMG discriminator has the following characters except low cost: 1) it has only discrimination teeth sections; 2) the thickness of each gear layer exceeds one hundred micrometers; 3) it is axially driven by a separate electronic magnetic micromotor directly; 4) its CMG is made of metal and is batch fabricated in the assembled state; 5) it is prevented from rotating in the opposite direction by pawl/ratchet wheel mechanism; 6) it has simpler structure. This device has better strength and reliability in abnormal environment compared to the existing surface micro machining (SMM) discriminator.

Sacrificial Anode Stability and Polarization Potential Variation in a Ternary Al-xZn-xMg Alloy in a Seawater-Marine Environment

在这，在海水的基于铝的牺牲的阳极的表演上的纸，锌(Zn ) 的效果和镁(Mg ) 增加用一个潜在的测量方法被调查。阳极的效率，保护效率，和极化的潜力是使用的参数。在阳极的 Zn 和 Mg 的百分比从 2% ～ 8% Zn 和 1% ～ 4% Mg 被改变。生产的合金在房间温度在海水为低碳钢的保护作为牺牲的阳极被测试。象 88.36% 一样高的当前的效率在包含 6% Zn 和 1% Mg 的合金被获得。获得为的极化的潜力联合(steel/Al-based 合金) 作为交上 Pourbaix 图，与在阳极的区域以内躺在免疫 region/cathodic 区域和牺牲的阳极以内的钢。牺牲的阳极在第 7 和第 8 星期以后提供给钢的保护被测量，保护效率象 99.66% 和 99.47% 为 Al-6%Zn-1%Mg 演员组阳极被完成一样高珍视。演员组阳极的微观结构六角形的 Mg 3 Zn2 和以身体为中心的立方的艾尔 2 Mg 3 Zn 3 。这些为被动氧化铝电影的故障可能负责，因此提高阳极效率。

Ritual Implements and Sacrificial Objects——Exhibits of Tibet Museum

Most TibetanBuddhist ritualimplements andsacrificialobjects were cast in gold,silver or copper, in additionto those made of wood,bone,stone,shells,cloth,silks and brocade heyconstitute an important partof he treasure house ofTibetan Buddhism.

Sacrificial Fires and Horsemanship in Yushu

ＳａｃｒｉｆｉｃｉａｌＦｉｒｅｓａｎｄＨｏｒｓｅｍａｎｓｈｉｐｉｎＹｕｓｈｕ￥／／ＧＹＡＹＵＮＧＱＵＮＰＥＳｉｎｃｅａｎｃｉｅｎｔｔｉｍｅｓ，Ｊｕｌｙｈａｓｂｅｅｎａｈｉｇｈｌｙｓｉｇｎｉｆｉｃａｎｔｒｅｌｉｇｉｏｕｓｍｏｎｔｈｄｕｒｉｎｇｗｈｉｃｈ...

碳化及氯盐侵蚀条件下锌牺牲阳极对钢筋保护行为研究

采用水泥基材料包覆的金属锌作为牺牲阳极,通过混凝土模拟孔溶液模拟碳化及氯离子侵蚀环境,研究牺牲阳极材料对钢筋的保护作用。电化学测试结果表明,当Q235钢片和纯锌片形成电偶对时,Q235钢在质量分数为1.5%的氯化钠溶液中易发生锈蚀,而在溶液中添加适量的碱(LiOH)以及卤素碱金属化合物(LiBr)能够激发金属锌持续溶解,持续提供牺牲阳极保护,有效抑制钢片的腐蚀。结合XRD测试结果可知:LiOH可以维持锌的溶解,并且与锌片反应生成锌的氢氧化物;卤素碱金属化合物可以诱发金属锌的腐蚀。相比于卤素碱金属化合物,加入高浓度LiOH对钢筋的阻锈效果更好。本研究有助于完善牺牲阳极材料的激发技术,提升牺牲阳极技术对钢筋的保护作用。

殷墟王陵四论

本文在前辈学者研究的基础上,进一步指出殷墟王陵始建于洹北商城时期,是洹北商城始建之时都邑格局的重要组成部分。新的考古发现仍说明殷墟王陵废弃于西周早期,这与周革殷命的政治策略有关。王陵东区大量祭祀坑的年代为殷墟早期,特别是武丁时期,大规模祭祀是“武丁中兴”重要的政治举措。以妇好为代表的诸多王族成员死后仍葬于宫殿宗庙区,反映出当时的族邑理念。

清代湖湘地区孔庙祭祀仪式与礼俗用乐

孔庙祭祀是对以儒学为代表的传统文化和以孔子为代表的历代贤哲的一种释典活动,在祭祀仪式活动中,礼俗用乐伴随着祀典的全部过程,这些音乐专门为祭孔祀典而制作,带有强烈的乐舞特征。清代湖湘地区盛行祭孔祀典,形成了直省祭孔与孔府家庙祭孔释奠的两大用乐体系,由于清代湖湘地区祭孔礼俗用乐体系的成熟及程序的完善,湖湘地区孔庙祭祀礼俗用乐在中国音乐发展史上有着举足轻重的地位。湖湘地区孔庙祭祀礼俗用乐有着独特的乐舞内容和表现形式,它历经了定乐、发展、缺失、重整等兴亡盛衰,虽然古制音律原貌难寻,但祭祀礼俗用乐与湖湘地方音乐之间形成了相互影响、相互依存的格局,同时也是孔庙祭祀音乐能够在湖湘地区传承、繁衍的基础条件。

事神与均惠:从儒家祭礼的两条脉络看中国社会的神圣性来源

《仪礼》中所有的《特性馈食礼》记载了儒家祭祀父祖之礼,这一礼经文本显露了儒家尝试通过蕴含“事神”和“均惠”这两条脉络的祭礼在宗族中激发“尊祖敬宗”情感的努力。其中,“事神”指的是作为主祭者的主人和主妇在宗族族人和宾客的帮助下馈享父祖,“均惠”指的是神惠通过礼仪动作下的饮食在父祖之神、主人主妇、宗族族人和宾客间流转。“事神”和“均惠”的双重礼意明确了神惠来源于祖先、流向宗族,达成了祖先与宗族共在的仪式效果,祭礼对于宗法制度的动态维续至关重要。宗族始终是中国社会的基础,儒家祭礼文本揭示了祖先是宗族神圣性的来源,这一神圣性亦通过宗族构成中国社会的基础和底色。