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| 1 | Performance of heavy ductile iron castings for windmills显示文摘The main objective of the present paper is to review the specific characteristics and performance obtaining conditions of heavy ductile iron(DI) castings,typically applied in windmills industry,such as hubs and rotor housings.The requirements for high impact properties in DI at low temperatures are part of the ENGJS-400-18U-LT(SRN 1563) commonly referred to as GGG 40.3(DIN 1693).Pearlitic in-uence factor(Px) and antinodularising action factor(K1) were found to have an important in-uence on the structure and mechanical properties,as did Mn and P content,rare earth(RE) addition and inoculation power.The presence of high purity pig iron in the charge is extremely beneficial,not only to control the complex factors Px and K1,but also to improve the 'metallurgical quality' of the iron melt.A correlation of C and Si limits with section modulus is very important to limit graphite nodule flotation.Chunky and surface-degenerated graphite are the most controlled graphite morphologies in windmills castings.The paper concluded on the optimum iron chemistry and melting procedure,Mg-alloys and inoculants peculiar systems,as well as on the practical solutions to limit graphite degeneration and to ensure castings of the highest integrity,typically for this field. | Iulian Riposan Mihai Chisamera Stelian Stan | 2010 | China Foundry2010,7,2: | 9 |
| 2 | New developments in high quality grey cast irons显示文摘The paper reviews original data obtained by the present authors,revealed in recent separate publications,describing specific procedures for high quality grey irons,and reflecting the forecast needs of the worldwide iron foundry industry.High power,medium frequency coreless induction furnaces are commonly used in electric melting grey iron foundries.This has resulted in low sulphur(<0.05wt.%)and aluminium(<0.005wt.%)contents in the iron,with a potential for higher superheating(>1,500°C),contributing to unfavourable conditions for graphite nucleation.Thin wall castings are increasingly produced by these electric melt shops with a risk of greater eutectic undercooling during solidification.The paper focused on two groups of grey cast irons and their specific problems:carbides and graphite morphology control in lower carbon equivalent high strength irons(CE=3.4%-3.8%),and austenite dendrite promotion in eutectic and slightly hypereutectic irons(CE=4.1%-4.5%),in order to increase their strength characteristics.There are 3 stages and 3 steps involving graphite formation,iron chemistry and iron processing that appear to be important.The concept in the present paper sustains a threestage model for nucleating flake graphite[(Mn,X)S type nuclei].There are three important groups of elements(deoxidizer,Mn/S,and inoculant)and three technological stages in electric melting of iron(superheat,pre-conditioning of base iron,final inoculation).Attention is drawn to a control factor(%Mn)x(%S)ensuring it equals to 0.03–0.06,accompanied by 0.005wt.%–0.010wt.%Al and/or Zr content in inoculated irons.It was found that iron powder addition promotes austenite dendrite formation in eutectic and slightly eutectic,acting as reinforcement for the eutectic cells.But,there is an accompanying possible negative influence on the characteristics of the(Mn,X)S type graphite nuclei(change the morphology of nuclei from polygonal compact to irregular polygonal,and therefore promote chill tendency in treated irons).A double addition(iron powder+inoculant)appears to be an effective treatment to benefit both austenite and graphite nucleation,with positive effects on the final structure and chill tendency. | Iulian Riposan Mihai Chisamera Stelian Stan | 2014 | China Foundry2014,11,4: | 8 |
| 3 | 大气二氧化氮与每日总死亡率、心血管和呼吸系统疾病死亡率的短期关联:398个城市的多中心分析显示文摘目的:采用统一的分析方案,评估全球多个国家/地区的二氧化氮(NO_(2))与总死亡率、心血管和呼吸系统疾病死亡率之间的短期关联。研究设计:采用两阶段的时间序列分析方法、过度离散的广义线性模型和多水平meta分析。研究地点:22个低到高收入国家/地区的398个城市。主要结局指标:1973—2018年逐日总死亡人数(6280万人)、心血管疾病死亡人数(1970万人)和呼吸系统疾病死亡人数(550万人)。结果:平均而言,NO_(2)浓度在滞后1天(前1天)每增加10μg/m^(3),会导致总死亡率、心血管和呼吸系统疾病死亡率分别增加0.46%(95%可信区间0.36%~0.57%)、0.37%(0.22%~0.51%)、0.47%(0.21%~0.72%)。在对共污染物(PM_(10)、PM_(2.5)、臭氧、二氧化硫和一氧化碳)进行调整后,这些关联仍然很稳定。所有3种死因的暴露-反应曲线几乎是线性的,没有明显的阈值。在398个城市中,可归因于高过假定零水平的NO_(2)浓度造成的死亡比例为1.23%(95%可信区间0.96%~1.51%)。结论:这项多中心研究提供了关于NO_(2)短期暴露与总死亡率、心血管和呼吸系统死亡风险之间的独立和线性关联的关键证据,说明通过加强NO_(2)的控制和监管限制标准,可获得人群水平的健康收益。 | 孟夏 刘聪(校) 陈仁杰 郑湃(译) 阚海东(校) Francesco Sera Ana Vicedo-Cabrera Ai Milojevic Maria Guo Yuming Tong Shilu Micheline de Sousa Zanotti Stagliorio Coelh Paulo Hilario Nascimento Saldiva Eric Lavigne Patricia Matus Correa Nicolas Valdes Ortega Samuel Osorio Garcia Jan Kysely Ales Urban Hans Orru Marek Maasikmets Jouni J K Jaakkola Niilo Ryti Veronika Huber Alexandra Schneider Klea Katsouyanni Antonis Analitis Masahiro Hashizume Yasushi Honda Chris Fook Sheng Ng Baltazar Nunes João Paulo Teixeira Iulian Horia Holobaca Simona Fratianni Ho Kim Aurelio Tobias Carmeníniguez Bertil Forsberg ChristoferÅström Martina S Ragettli Yue-Liang Leon Guo Shih-Chun Pan Shanshan Li Michelle L Bell Antonella Zanobetti Joel Schwartz Tangchun Wu Antonio Gasparrini | 2021 | 英国医学杂志中文版2021,24,8: | 7 |
| 4 | Thermal analysis control of in-mould and ladle inoculated grey cast irons显示文摘The effect of addition of 0.05wt.% to 0.25 wt.% Ca,Zr,Al-FeSi alloy on in-ladle and in-mould inoculation of grey cast irons was investigated.In the present paper,the conclusions drawn are based on thermal analysis.For the solidification pattern,some specific cooling curves characteristics,such as the degree of undercooling at the beginning of eutectic solidif ication and at the end of solidifi cation,as well as the recalescence level,are identif ied to be more influenced by the inoculation technique.The degree of eutectic undercooling of the electrically melted base iron having 0.025% S,0.003% Al and 3.5% Ce is excessively high(39-40℃),generating a relatively high need for inoculation.Under these conditions,the in-mould inoculation has a more signif icant effect compared to ladle inoculation,especially at lower inoculant usage(less than 0.20 wt.%).Generally,the eff iciency of 0.05wt.% -0.15wt.% of alloy for in-mould inoculation is comparable to,or better than,that of 0.15wt.% -0.25wt.% addition in ladle inoculation procedures.In order to secure stable and controlled processes,representative thermal analysis parameters could be used,especially in thin wall grey iron castings production. | Mihai Chisamera Iulian Riposan Stelian Stan Eduard Stefan George Costache | 2009 | China Foundry2009,6,2: | 4 |
| 5 | Complex(Mn,X)S compounds-major sites for graphite nucleation in grey cast iron显示文摘Despite the cubic system,the ability of sulphides to nucleate graphite can be enhanced by inoculating elements which transform them in complex compounds with a better lattice matching to graphite,a low coagulation capacity,good stability and adequate interfacial energy.(Mn,X)S compounds,usually less than 5.0μm in size,with an average 0.4-2.0μm well defined core(nucleus),were found to be important sites for graphite nucleation in grey irons.A three-stage model for the nucleation of graphite in grey irons is proposed:(1)Very small micro-inclusions based on strong deoxidizing elements(Mn,Si,Al,Ti,Zr)are formed in the melt;(2)Nucleation of complex(Mn,X)S compounds at these previously formed micro-inclusions;(3)Graphite nucleates on the sides of the(Mn,X)S compounds with lower crystallographic misfit.Al appears to have a key role in this process,as Al contributes to the formation of oxides in the first stage and favors the presence of Sr and Ca in the sulphides,in the second stage.The 0.005-0.010%Al range was found to be beneficial for lower undercooling solidification,type-A graphite formation and carbides avoidance. | Iulian Riposan Mihai Chisamera Stelian Stan Doug White | 2009 | China Foundry2009,6,4: | 4 |
| 6 | Evaluation on the corrosion resistance, antibacterial property and osteogenic activity of biodegradable Mg-Ca and Mg-Ca-Zn-Ag alloys显示文摘The rapid degradation of magnesium(Mg)-based implants in physiological environment limits its clinical applications, and alloying treatment is an effective way to regulate the degradation rate of Mg-based materials. In the present study, three Mg alloys, including Mg-0.8Ca(denoted as ZQ), Mg-0.8Ca-5Zn-1.5Ag(denoted as ZQ71) and Mg-0.8Ca-5Zn-2.5Ag(denoted as ZQ63), were fabricated by alloying with calcium(Ca), zinc(Zn) and silver(Ag). The results obtained from electrochemical corrosion tests and in vitro degradation evaluation demonstrated that the three Mg alloys exhibited distinct corrosion resistance, and ZQ71 exhibited the lowest degradation rate in vitro among them. After addition of Zn and Ag, the antibacterial potential of Mg alloys was also enhanced. The in vitro cell experiments showed that all the three Mg alloys had good biocompatibility. After implantation in a rat femoral defect, ZQ71 showed significantly higher osteogenic activity and bone substitution rate than ZQ63 and ZQ, due to its higher corrosion resistance as well as the stimulatory effects of the released metallic ions. In addition, the average daily degradation rate of each Mg alloy in vivo was significantly higher than that in vitro, as could be due to the implantation site located in the highly vascularized trabecular region. Importantly, the correlations between the in vitro and in vivo degradation parameters of the Mg alloys were systematically analyzed to find out the potential predictors of the in vivo degradation performance of the materials. The current work not only evaluated the clinical potential of the three biodegradable Mg alloys as bone grafts but also provided a feasible approach for predicting the in vivo degradation behavior of biodegradable materials. | Hewei Chen Bo Yuan Rui Zhao Xiao Yang Zhanwen Xiao Antoniac Aurora Bita Ana Iulia Xiangdong Zhu Antoniac Vasile Iulian Xingdong Zhang | 2022 | Journal of Magnesium and Alloys2022,10,12: | 3 |
| 7 | Construction of a magnesium hydroxide/graphene oxide/hydroxyapatite composite coating on Mg-Ca-Zn-Ag alloy to inhibit bacterial infection and promote bone regeneration显示文摘The improved corrosion resistance, osteogenic activity, and antibacterial ability are the key factors for promoting the large-scale clinical application of magnesium (Mg)-based implants. In the present study, a novel nanocomposite coating composed of inner magnesium hydroxide, middle graphene oxide, and outer hydroxyapatite (Mg(OH)_(2)/GO/HA) is constructed on the surface of Mg-0.8Ca-5Zn-1.5Ag by a combined strategy of hydrothermal treatment, electrophoretic deposition, and electrochemical deposition. The results of material characterization and electrochemical corrosion test showed that all the three coatings have high bonding strength, hydrophilicity and corrosion resistance. In vitro studies show that Mg(OH)2 indeed improves the antibacterial activity of the substrate. The next GO and GO/HA coating procedures both promote the osteogenic differentiation of MC3T3-E1 cells and show no harm to the antibacterial activity of Mg(OH)2 coating, but the latter exhibits the best promoting effect. In vivo studies demonstrate that the Mg alloy with the composite coating not only ameliorates osteolysis induced by bacterial invasion but also promotes bone regeneration under both normal and infected conditions. The current study provides a promising surface modification strategy for developing multifunctional Mg-based implants with good corrosion resistance, antibacterial ability and osteogenic activity to enlarge their biomedical applications. | Bo Yuan Hewei Chen Rui Zhao Xuangeng Deng Guo Chen Xiao Yang Zhanwen Xiao Antoniac Aurora Bita Ana Iulia Kai Zhang Xiangdong Zhu Antoniac Vasile Iulian Shen Hai Xingdong Zhang | 2022 | Bioactive Materials2022,7,12: | 2 |
| 8 | Surface Graphite Degeneration in Ductile Iron Castings for Resin Molds显示文摘The objective of this paper is to review the factors influencing the formation of degenerated graph- ite layers on the surfaces of ductile iron castings for chemical resins-acid molding and core-making systems and how to reduce this defect. In the resin mold technique the sulphur in the P-toluol sulphonic acid (PTSA), usually used as the hardener, has been identified as one factor causing graphite degeneration at the metal- mold interface. Less than 0.15% S in the mold (or even less than 0.07% S) can reduce the surface layer depth. Oxygen may also have an effect, especially for sulphur containing systems with turbulent flows in the mold, water-bearing no-bake binder systems, Mg-Silica reactions, or dross formation conditions. Despite the lower level of nitrogen in the iron melt after magnesium treatment (less than 90 ppm), nitrogen bearing res- ins have a profound effect on the frequency and severity of surface pinholes, but a limited influence on sur- face graphite degeneration. | Iulian Riposan Mihai Chisamera Stelian Stan Torbjorn Skaland | 2008 | Tsinghua Science and Technology2008,13,2: | 2 |
| 9 | Novel eco-efficient reactive distillation process for dimethyl carbonate production by indirect alcoholysis of urea显示文摘Dimethyl carbonate is an eco-friendly essential chemical that can be sustainably produced from CO_(2),which is available from carbon capture activities or can even be captured from the air.The rapid increase in dimethyl carbonate demand is driven by the fast growth of polycarbonates,solvent,pharmaceutical,and lithium-ion battery industries.Dimethyl carbonate can be produced from CO_(2)through various chemical pathways,but the most convenient route reported is the indirect alcoholysis of urea.Previous research used techniques such as heat integration and reactive distillation to reduce the energy use and costs,but the use of an excess of methanol in the trans-esterification step led to an energy intensive extractive distillation required to break the dimethyl carbonate-methanol azeotrope.This work shows that the production of dimethyl carbonate by indirect alcoholysis of urea can be improved by using an excess of propylene carbonate(instead of an excess of methanol),a neat feat that we showed it requires only 2.64 kW·h·kg^(-1) dimethyl carbonate in a reaction-separation-recycle process,and a reactive distillation column that effectively replaces two conventional distillation columns and the reactor for dimethyl carbonate synthesis.Therefore,less equipment is required,the methanol-dimethyl carbonate azeotrope does not need to be recycled,and the overall savings are higher.Moreover,we propose the use of a reactive distillation column in a heat integrated process to obtain high purity dimethyl carbonate(>99.8 wt-%).The energy requirement is reduced by heat integration to just 1.25 kW·h·kg^(-1) dimethyl carbonate,which is about 52%lower than the reaction-separation-recycle process.To benefit from the energy savings,the dynamics and control of the process are provided for10%changes in the nominal rate of 32 ktpy dimethyl carbonate,and for uncertainties in reaction kinetics. | Iulian Patrașcu Costin S.Bîldea Anton A.Kiss | 2022 | Frontiers of Chemical Science and Engineering2022,16,2: | 2 |
| 10 | Improving chill control in iron powder treated slightly hypereutectic grey cast irons显示文摘Recent studies revealed that in eutectic to slightly hypereutectic grey irons(CE = 4.3%-4.5%) the presence of austenite dendrites provides an opportunity to improve the cast iron properties,as a high number of eutectic cells are 'reinforced' by austenite dendrites.An iron powder addition proved to be important by promoting dendritic austenite in hypereutectic irons,but was accompanied by adverse effect on the characteristics of potential nuclei for graphite.The purpose of the present paper is to investigate the solidification pattern of these irons.Chill wedges with different cooling moduli(CM = 0.11-0.43 cm) were poured in resin bonded sand and metal moulds.Relative clear /mottled /total chill measurement criteria were applied.Iron powder additions led to a higher chill tendency,while single inoculation showed the strongest graphitizing effect.The various double treatments show an intermediate position,but the inoculant added after iron powder appears to be the most effective in reducing base iron chill tendency,for all cooling moduli and chill evaluation parameters.This performance reflects the improved properties of(Mn,X)S polygonal compounds as nucleation sites for graphite,especially in resin bonded sand mould castings.Both austenite and graphite nucleation benefit from a double addition of iron powder + inoculant,with positive effect on the final structure and chill tendency. | Iulian Riposan Mihai Chisamera Stelian Stan Michael Barstow | 2011 | China Foundry2011,8,2: | 2 |
| 11 | Simultaneous thermal and contraction/expansion curves analysis for solidification control of cast irons显示文摘The first part of the paper summarizes the performance of two mould devices,illustrating by representative shrinkage tendency results in ductile cast iron as affected by mould rigidity(green and furan resin sand moulds)and inoculant type(FeSi-based alloys).Less rigid green sand moulds encourage the formation of contraction defects,not only because of the high initial expansion values(ε(di))(max),but also because of the increased solidification undercooling.A high inoculation efficiency means not only lowering the carbides formation sensitivity and increasing the nodule count,but also a prolonged graphitization through to the end of the eutectic freezing,as observed by the high population of small late forming nodules,which leads to minimizing the tendency for shrinkage.The second part of the paper illustrates an application of this equipment to commercial foundry use.It conducts thermal analysis and volume change measurements in a single ceramic cup with cast iron quality as a variable.La-bearing FeSi inoculant appears to be more effective than RE(Rare Earth)-FeSi alloy in FeSiMgCa treated irons(no RE),in terms of reducing eutectic undercooling and(ε(di))(max),favourable for lower sensitivity to shrinkage formation.Experiments also compared solidification patterns for white[WI],grey[GI]and ductile[DI]irons,to correlate the most important events between the cooling curves and contraction curves,to evaluate the sensitivity to shrinkage formation.All of the irons have similar values for initial expansion up to the start of eutectic freezing,but,after that,the graphite formation promotes expansion(more than 5 times for nodular graphite),resulting in a difference in maximum expansion(2 times higher for DI).The graphitic expansion has two contrary effects.Increased graphitic expansion(force)leads to a higher shrinkage sensitivity during the first part of the eutectic reaction,but also to a decrease of shrinkage at the end of solidification,due to forcing the last liquid iron to occupy the previous formed cavities.Consequently,strong graphitization process promotion at the end of solidification favours the castings'soundness. | Iulian Riposan Stelian Stan Mihai Chisamera Loredana Neacsu Ana Maria Cojocaru Eduard Stefan Iuliana Stan | 2020 | China Foundry2020,17,2: | 2 |
| 12 | The effect of HRG gas addition on diesel engine combustion characteristics and exhaust emissions显示文摘 | Adrian Birtas Iulian Voicu Cristian Petcu Radu Chiriac Nicolae Apostolescu | 2011 | International Journal of Hydrogen Energy2011,,18: | 1 |
| 13 | Carbonate rock characterization and modeling Capillary pressure and permeability in multimodal rocks: A look beyond sample specific heterogeneity显示文摘 | Iulian N H Chris A N | 2012 | AAPG Bulletin2012,96,9: | 1 |
| 14 | Op- timization of variable speed wind power systems based on a LQG approach 显示文摘 | IULIAN M CUTULULIS N A ANTONETA I B | 2005 | Control Engineering Practice2005,13,7: | 1 |
| 15 | Optimization of variable speed wind power systems based on a LQG approach显示文摘 | Iulian Munteanu Nicolaos Antonio Cutululis Antoneta Iuliana Brateu | 2005 | Control Engineering Practice2005,13,7: | 1 |
| 16 | Numerical and experimental investigation of buoyancy effects in a plate heat exchanger显示文摘 | IULIAN G MATTHEW T NICOLAS G | 2013 | Applied Thermal Engineering2013,51,: | 1 |
| 17 | Structural design of planar mechanisms with dyads显示文摘 | IULIAN P DAN B M | 2008 | Multi Body System Dynamics2008,19,4: | 1 |
| 18 | In vitro characterization of novel nanostructured collagen-hydroxyapatite composite scaffolds doped with magnesium with improved biodegradation rate for hard tissue regeneration显示文摘New materials are required for bone healing in regenerative medicine able to temporarily substitute damaged bone and to be subsequently resorbed and replaced by endogenous tissues.Taking inspiration from basic composition of the mammalian bones,composed of collagen,apatite and a number of substitution ions,among them magnesium(Mg2+),in this work,novel composite scaffolds composed of collagen(10%)-hydroxyapatite(HAp)(90%)and collagen(10%)-HAp(80%)-Mg(10%)were developed.The lyophilization was used for composites preparation.An insight into the nanostructural nature of the developed scaffolds was performed by Scanning Electron Microscopy coupled with Energy Dispersive X-Ray and Transmission Electron Microscopy coupled with Energy Dispersive X-Ray.The HAp nanocrystallite clusters and Mg nanoparticles were homogeneously distributed within the scaffolds and adherent to the collagen fibrils.The samples were tested for degradation in Simulated Body Fluid(SBF)solution by soaking for up to 28 days.The release of Mg from collagen(10%)-HAp(80%)-Mg(10%)composite during the period of up to 21 days was attested,this composite being characterized by a decreased degradation rate with respect to the composite without Mg.The developed composite materials are promising for applications as bone substitute materials favouring bone healing and regeneration. | Iulian V.Antoniac Aurora Antoniac Eugeniu Vasile Camelia Tecu Marco Fosca Viktoriya G.Yankova Julietta V.Rau | 2021 | Bioactive Materials2021,6,10: | 1 |
| 19 | FT-IR study of the ring-retaining products from the reaction of OH radicals with phenol,o-,m-,and p-cresol显示文摘 | Romeo Iulian Olariu Bjorn Klotz | 2002 | Atmospheric Environment2002,36,: | 1 |
| 20 | Wind turbulence used as searching signal for MPPT in variable-speed wind energy conversion systems显示文摘 | Munteanua Iulian Bratcu Antoneta Iuliana Ceangǎ Emil | | 0,,01: | 1 |