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Multi-walled Carbon Nanotubes as a Ligand in nickel ?-Diimine Based Ethylene Polymerization

Chinese Journal of Polymer Science 2015年第10期33卷 1389-1403页

作者： Sasan Talebnezhad saeed Pourmahdian Department of Polymer Engineering and Color Technology Amirkabir University of Technology

Two novel heterogeneous nickel a-diimine based polymerization catalysts, containing MWCNT as the main ligand, were synthesized by novel in situ catalyst preparation technique. The in situ synthesis was performed by covalent attachment of the acenaphthenic ligand core to amine functionalized MWCNT ligand arms through diimine bonding and further nickel dibromide chelation. The prepared catalysts were fully characterized and their structures and supporting efficiencies were determined. Single or double introduction of the MWCNTs through their ends or sidewall（s） in the catalytic system, as a ligand, influenced the catalytic performance, microstructure and morphology of obtained polyethylenes. MWCNT sidewall bonding to para-aryl position of the tetramethylphenyl moiety performed as more electron-donating ligand than MWCNT ends linked to the imine bond and protected the catalytic system to retain its activity. This character resulted in the maintenance of the resulting polymer topology at elevated temperatures so that the catalytic activity and the obtained polymer melting points remained around 110 g PE·mmol^-1 ni·h^-1 and 123 ℃ in all polymerization temperatures respectively. In polymerization trials, molecular weight fall against temperature was not as sharp as what had been observed in sequentially prepared catalysts insofar as the molecular weight of resultant polymer at 60 ℃ reached to 310000 g·mol^-1 which was close to the highest value had been reported at 30 ℃ for sequentially prepared catalysts. TEM observations showed the presence of the stopped-growth polymer chains due to geometrical constrains or ligand debonding for both catalytic systems.

关键词： a-Diiminonickel catalyst Ligand Multi-walled carbon nanotubes Ethylene polymerization In situ catalyst preparation.

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Evaluation of sediment contamination in the Red Sea coastal area combining multiple pollution indices and multivariate statistical techniques

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International Journal of Sediment Research 2021年第2期36卷 243-254页

作者： Yousef saeed Saleh Biology Department Faculty of Science Taiz University

In the recent years, the Red Sea coast of Yemen has been severely affected by intensive anthropogenic activities. The current study constitutes a thorough inquiry to evaluate the extent of heavy metals pollution in Yemen’s Red Sea coast sediment and identifies the possible sources of pollution. The concentrations of five metals(copper(Cu), zinc(Zn), cadmium(Cd), lead(Pb), and nickel(ni)) collected from nine sites along the Red Sea coast of Yemen were assessed using an atomic absorption spectrophotometer(ASS). Sediment quality indices, such as the sediment quality guidelines(SQGs), potential ecological risk(RI), contamination factor(CF), pollution load index(PLI), geoaccumulation index(Igeo), and modified degree of contamination(m Cd) were computed. In addition, multivariate statistical techniques(principal component analysis(PCA),hierarchical cluster analysis, and Pearson’s correlation analysis) were applied to identify the potential sources of metals. The mean concentrations of Cu, Zn, Cd, Pb, and ni were 51.3, 61.9, 4.02, 9.9, and 33.4 mg/kg dry wt, respectively. The spatial distribution revealed that the metals concentrations were high at the middle zone and low southward of Hodeida city. According to the SQGs, the adverse biological effects of metals were occasionally associated with Cu and Cd, frequently associated with ni, and not expected to occur with Zn and Pb. The RI indicated that the sediment of the studied sites pose low(RI ni > Pb > Cd > Cu,whereas the PLI and m Cd indicated that Ras Isa(Site 5) and Urj village(Site 6) were the most polluted ***, cluster analysis, and correlation analysis found that Cd, Pb, and ni mostly originated from anthropogenic

关键词： Red Sea Heavy metals Pollution Spatial distribution Sediment quality

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Microstructure,mechanical properties and corrosion behavior of Al-Si-Cu-Zn-X(X=Bi,Sb,Sr) die cast alloy

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Transactions of Nonferrous Metals Society of China 2016年第1期26卷 28-38页

作者： saeed FARAHANY Ali OURDJ1ni Hamid Reza BAKHSHESHI-RAD Department of Materials and Mechanical Engineering Buein Zahra Technical UniversityQazvin 345 1745346Iran Department of Mechanical Engineering Faculty of EngineeringUniversity of OttawaOttawa161 Louis PasteurKIN 6N5Canada Department of Materials Manufacturing and Industrial EngineeringFaculty of Mechanical EngineeringUniversiti Teknologi Malaysia(UTM)Johor Bahru 81310Malaysia

The microstructure evolution, mechanical and corrosion properties of Al-11Si-2Cu-0.8Zn die cast alloy treated with Bi, Sb and Sr additions were investigated. The results of mechanical testing showed that all additions increased impact toughness, ultimate tensile strength, and elongation of the alloy as a result of change in eutectic Si morphology. The analysis of fracture surfaces revealed that with addition of Sr and to lesser extent Bi and Sb, the alloy exhibited a predominantly ductile fracture rather than quasi-cleavage brittle fracture. Moreover, with the additions of Sr, Bi and Sb, the quality index increased to 164.7 MPa, 156.3 MPa and 152.6 MPa respectively from 102 MPa for the base alloy. Polarization corrosion tests conducted in sodium chloride solution showed that the corrosion potential shifted to more negative values with additions of Sb, Bi and Sr, respectively. Corrosion immersion tests also revealed that the element additions have a detrimental effect on the corrosion rate of alloys, due to the increase of boundaries between the Al and eutectic Si phases.

关键词： aluminium die cast alloy melt treatment mechanical properties fracture corrosion

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Effect of niO-niCr2O4 nano-oxides on the microstructural,mechanical and corrosion properties of ni-coated carbon steel

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International Journal of Minerals,Metallurgy and Materials 2023年第6期30卷 1078-1092页

作者： saeed Mojallal Hurieh Mohammadzadeh Abbas Aghaeinejad-Meybodi Robabeh Jafari Materials Engineering Department Faculty of EngineeringUrmia UniversityUrmiaIran Chemical Engineering Department Faculty of EngineeringUrmia UniversityUrmiaIran

Pure ni and its composites with different percentages of ni-Cr nano-oxides were coated over carbon steel to assess the coating features and mechanical and corrosion behavior.A nano-oxide composite of ni-Cr was first synthesized through chemical coprecipitation with uniform distribution *** was employed to coat pure ni and ni-(ni-Cr)oxides(10,20,30,40,and 50 g/L)on the steel *** electron microscope and field emission scanning electron microscope were adopted to examine the microstructure of powders and coatings,and X-ray diffraction analysis was employed to study the chemical *** microhardness,thickness,and wear resistance of the coatings were assessed,polarization and electrochemical impedance spectroscopy(EIS)tests were conducted to analyze the corrosion behavior,and the corresponding equivalent circuit was *** showed flawless and crack-free coatings for all samples and uniform distribution of nano-oxides in the ni matrix for the samples of 10-30 g/*** oxides were detected at high *** microhardness(HV 661),thickness(116μm),and wear resistance of coatings were found at 30 g/L.A three-loop equivalent circuit corresponded satisfactorily to all EIS *** corrosion resistance increased with the nano-oxide concentration of up to 30 g/L but decreased at 40 g/*** sample of 50 g/L showed the best corrosion resistance.

关键词： nanocomposite powder electroplating coating corrosion resistance electrochemical impedance spectroscopy wear resistance

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Investigation on the homogenization treatment and element segregation on the microstructure of a γ/γ′-cobalt-based superalloy

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International Journal of Minerals,Metallurgy and Materials 2019年第2期26卷 222-233页

作者： saeed Aliakbari Sani Hossein Arabi Shahram Kheirandish Golamreza Ebrahimi School of Materials and Metallurgical Engineering Iran University of Science and Technology ((IUST)) School of Materials and Metallurgical Engineering Iran University of Science and Technology (IUST) Materials and Polymers Engineering Department Faculty of Engineering Hakim Sabzevari University

The aim of the present study was to investigate the effect of element segregation on the microstructure and γ′ phase in a γ/γ′ cobalt-based superalloy. Several samples were prepared from a cast alloy and homogenized at 1300°C for different times, with a maximum of 24 h. A microstructural study of the cast alloy using wavelength-dispersive spectroscopic analysis revealed that elements such as Al, Ti, and ni segregated mostly within interdendritic regions, whereas W atoms were segregated within dendrite cores. With an increase in homogenization time, segregation decreased and the initial dendritic structure was eliminated. Field-emission scanning electron microscopy micrographs showed that the γ′ phases in the cores and interdendritic regions of the as-cast alloy were 392 and 124 nm, respectively. The size difference of γ′ was found to be due to the different segregation behaviors of constituent elements during solidification. After homogenization, particularly after 16 h, segregation decreased; thus, the size, chemical composition, and hardness of the precipitated γ′ phase was mostly uniform throughout the samples.

关键词： superalloy segregation homogenization microstructure γ′phase

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Wear and Friction Properties of Electrodeposited ni-Based Coatings Subject to Nano-enhanced Lubricant and Composite Coating

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Acta Metallurgica Sinica(English Letters) 2016年第10期29卷 902-910页

作者： Rizwan Bajwa Zulfiqar Khan H.Nazir Vivek Chacko Adil saeed NanoCorr Energy and Modelling Research GroupBournemouth University

This paper presents research findings on the tribological performance of electrodeposited coatings subject to nano-lubricants with the addition of nano-Al2O3 and graphene and ni/nano-Al2O3 composite coatings. Electrodeposited coatings were produced by using a pulse electrodeposition method. Tribological experiments were conducted by using a linear reciprocating ball on fiat sliding tribometer. Experimental results confirmed that the wear and friction resistance properties were significantly enhanced by doping of nano-effects in the lubricating oil and composite coating. The addition of Al2O3 nanoparticles in the lubricating oil showed the best tribological properties, followed by ni-Al2O3 composite coatings and nano-oil with graphene. The surface morphology and microstructure of electrodeposited coatings were examined by scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction. The wear mechanisms of these coatings subjected to tribological testing were investigated by post-test surface analyses. This research provides a novel approach to design durable nano-coatings for tribological applications in various industries such as automotive, aerospace, locomotive and renewable energy technologies.

关键词： Tribology Nanoparticles Graphene Nano-additives Nano-coatings

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Assessing Lateral Continuity within the Yammama Reservoir in the Foroozan Oilfield, Offshore Iran: An Integrated Study

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Acta Geologica Sinica(English Edition) 2018年第6期92卷 2405-2415页

作者： Payam HASSANZADEH Ahmad Reza RABBAni Ardeshir HEZARKHAni saeed KHAJOOIE Department of Petroleum Engineering Amirkabir University of Technology Department of Mining and Metallurgy Engineering Amirkabir University of Technology Department of Reservoir Engineering Exploration Directorate of National Iranian Oil Company (NIOC-EXP)

Located in Iranian sector of the Persian Gulf, Foroozan Oilfield has been producing hydrocarbons via seven different reservoirs since the 1970 s. However, understanding fluid interactions and horizontal continuity within each reservoir has proved complicated in this field. This study aims to determine the degree of intra-reservoir compartmentalization using gas geochemistry, light hydrocarbon components, and petroleum bulk properties, comparing the results with those obtained from reservoir engineering indicators. For this purpose, a total of 11 samples of oil and associated gas taken from different producing wells in from the Yammama Reservoir were selected. Clear distinctions, in terms of gas isotopic signature and composition, between the wells located in northern and southern parts of the reservoir(i.e. lighter δ13 C1, lower methane concentration, and negative sulfur isotope in the southern part) and light hydrocarbon ratios(e.g. nC 7/toluene, 2,6-dmC7/1,1,3-tmcyC5 and m-xylene/4-mC8) in different oil samples indicated two separate compartments. Gradual variations in a number of petroleum bulk properties(API gravity, V/ni ratios and asphaltene concentration) provided additional evidence on the reservoir-filling direction, signifying that a horizontal equilibrium between reservoir fluids across the Yammama Reservoir is yet to be achieved. Finally, differences in water-oil contacts and reservoir types further confirmed the compartmentalization of the reservoir into two separate compartments.

关键词： reservoir compartmentalization gas geochemistry light hydrocarbons reservoir engineering Yammama Reservoir Foroozan Oilfield Iran

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Electro-optic tuning of a single-frequencyultranarrow linewidth microdisk laser

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Advanced Photonics 2022年第3期4卷 105-113页

作者： Jintian Lin saeed Farajollahi Zhiwei Fang ni Yao Renhong Gao Jianglin Guan Li Deng Tao Lu Min Wang Haisu Zhang Wei Fang Lingling Qiao Ya Cheng Chinese Academy of Sciences(CAS) Shanghai Institute of Optics and Fine Mechanics(SIOM)State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-Intense Laser ScienceShanghaiChina University of Chinese Academy of Sciences Center of Materials Science and Optoelectronics EngineeringBeijingChina University of Victoria Department of Electrical and Computer EngineeringVictoriaBritish ColumbiaCanada East China Normal University School of Physics and Electronic ScienceXXL—The Extreme Optoelectromechanics LaboratoryShanghaiChina Research Center for Intelligent Sensing Zhejiang LabHangzhouChina Zhejiang University College of Optical Science and EngineeringThe Interdisciplinary Center for Quantum InformationState Key Laboratory of Modern Optical InstrumentationHangzhouChina East China Normal University State Key Laboratory of Precision SpectroscopyShanghaiChina Jiaxing Institute of Zhejiang University Intelligent Optics&Photonics Research CenterJiaxingChina Shanxi University Collaborative Innovation Center of Extreme OpticsTaiyuanChina Shandong Normal University Collaborative Innovation Center of Light Manipulations and ApplicationsJinanChina Shanghai Research Center for Quantum Sciences Shang

Single-frequency ultranarrow linewidth on-chip microlasers with a fast wavelength tunability play a game-changing role in a broad spectrum of applications ranging from coherent communication,light detection and ranging,to metrology and *** and fabrication of such light sources remain a challenge due to the difficulties in making a laser cavity that has an ultrahigh optical quality(Q)factor and supports only a single lasing frequency ***,we demonstrate a unique single-frequency ultranarrow linewidth lasing mechanism on an erbium ion-doped lithium niobate(LN)microdisk through simultaneous excitation of high-Q polygon modes at both pump and laser *** the polygon modes are sparse within the optical gain bandwidth compared with the whispering gallery mode counterpart,while their Q factors(above 10 million)are even higher due to the significantly reduced scattering on their propagation paths,single-frequency lasing with a linewidth as narrow as 322 Hz is *** measured linewidth is three orders of magnitude narrower than the previous record in on-chip LN ***,enabled by the strong linear electro-optic effect of LN,real-time electro-optical tuning of the microlaser with a high tuning efficiency of∼50 pm∕100 V is demonstrated.

关键词： lasers lithium niobate microcavities integrated opti

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Environmental Impact Assessment of Heavy Metals in Surface Disposed Drilling Waste

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Journal of Geoscience and Environment Protection 2021年第9期9卷 227-238页

作者： Ullattumpoyil Nasir M. Absi saeed S. Marzooq Yousif Southern Area Technical Support Department Saudi Aramco Dhahran KSA

Saudi Arabia has some of the biggest oil and gas reserves in the world, and has expanded its drilling operations gradually to meet the global demand. Improper handling of contaminated drilling wastes may cause serious negative environmental impacts. The current study investigates the toxicological effects of heavy metals in drilling waste by quantification and developing different contamination indices. Solid and liquid samples from different drilling waste pits were collected and analyzed for heavy metals. The average concentration varies significantly and decreases in the order of Fe > Al > Sr > Mn > Cu > Cr > Zn > Ni > Pb > Cd > Ag > Co. The spatial variation showed the highest concentration at SDGM Site 1, West. Comparison of current data showed continental crust average values within the specifications for most of the sites. For metals like Cd, Cr and Cu, the concentration is higher than the continental crust value. Indices such as pollution load index, modified degree of contamination etc. were calculated from the available data. The contamination level for different site calculations showed nil to a very low degree of contamination. Spatial variation of the contamination level indicated com

关键词： Petroleum Drilling Waste Heavy Metals Toxicity

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Improvement of thermally grown oxide layer in thermal barrier coating systems with nano alumina as third layer

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Transactions of Nonferrous Metals Society of China 2013年第5期23卷 1322-1333页

作者： Mohammadreza DAROONPARVAR Muhamad Azizi Mat YAJID Noordin Mohd YUSOF saeed FAR AHANY Mohammad Sakhawat HUSSAIN Hamid Reza BAKHSHESHIRAD Z.VALEFI Ahmad ABDOLAHI Department of Materials Manufacturing and Industrial EngineeringFaculty of Mechanical EngineeringUniversiti Teknologi Malaysia School of Metallurgy and Materials College of EngineeringUniversity of Tehran

A thermally grown oxide （TGO） layer is formed at the interface of bond coat/top coat. The TGO growth during thermal exposure in air plays an important role in the spallation of the ceramic layer from the bond coat. High temperature oxidation resistance of four types of atmospheric plasma sprayed TBCs was investigated. These coatings were oxidized at 1000 °C for 24, 48 and 120 h in a normal electric furnace under air atmosphere. Microstructural characterization showed that the growth of the TGO layer in nano niCrAlY/YSZ/nano Al2O3 coating is much lower than in other coatings. Moreover, EDS and XRD analyses revealed the formation of ni（Cr,Al）2O4 mixed oxides （as spinel） and niO onto the Al2O3 （TGO） layer. The formation of detrimental mixed oxides （spinels） on the Al2O3 （TGO） layer of nano niCrAlY/YSZ/nano Al2O3 coating is much lower compared to that of other coatings after 120 h of high temperature oxidation at 1000 °C.

关键词： high temperature oxidation nano thermal barrier coatings TGO layer spinels

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