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  • 1.
    Jain, Ayush
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Somberg, Julian
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Development and Characterisation of Multi-Scale Carbon Reinforced PPS Composites for Tribological Applications2019Ingår i: Lubricants, E-ISSN 2075-4442, Vol. 7, nr 4, artikel-id 34Artikel i tidskrift (Refereegranskat)
    Abstract [en]

     Polymer-based materials show to be of increasing interest in replacing metal based

    materials in tribological applications due to their low weight, cost and easy manufacturability.

    To further reduce the environmental impact of these bearing materials recyclability is becoming

    more crucial, stimulating the need for high performing thermoplastic materials. In this study,

    polyphenylene sulfide (PPS) composites were prepared in an effort to enhance the polymers’

    tribological properties. Short carbon fibres (SCFs), graphene oxide (GO) and nano diamonds (NDs)

    as well as polytetrafluoroethylene (PTFE) were used as micro and nano reinforcements. The addition

    of SCFs especially decreased the linear coefficient of thermal expansions while enhancing the

    micro hardness and wettability of the polymer. Under water lubricated conditions, a decrease

    in friction up to 56% and a reduction of wear rate in the order of 103  was observed by the addition

    of SCF. The reduction in friction and wear was further enhanced by the addition of NDs, providing

    a synergistic effect of the reinforcements in micro and nano scale. By testing the individual

    reinforcements under dry conditions, PTFE and SCFs were especially effective in reducing friction

    while the release and consequent abrasion of NDs and SCFs increased the wear under a higher

    contact pressure.

  • 2.
    Palmeira Belotti, Luca
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Vadivel, Hari Shankar
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Tribological performance of hygrothermally aged UHMWPE hybrid composites2019Ingår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 138, s. 150-156Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work, the effect of hygrothermal aging on friction and wear of water lubricated, Ultra High Molecular Weight Polyethylene (UHMWPE) hybrid composites were evaluated. Graphene Oxide (GO), Nano Diamonds (ND) and Short Carbon Fibers (SCF) were used as reinforcements as they previously exhibited promising improvements in the tribological behavior of UHMWPE in water-lubricated sliding contacts. Hygrothermal aging and pin-on-disc tribological experiments were performed to evaluate the response of the UHMWPE composites. It was observed that the friction and wear of the composites were not significantly affected by the aging conditions, which was attributed to the structural integrity of the newly developed UHMWPE based hybrid composites.

  • 3.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Biocompatibility, Mechanical and Tribological properties of GO reinforced thermoplastic polymer”. Flow Process Composite Materials Conference2018Konferensbidrag (Refereegranskat)
  • 4.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Design and manufacturing of Graphene Oxide reinforced high performing thermoplastics hybrid composites for Tribological applications2018Konferensbidrag (Övrigt vetenskapligt)
  • 5.
    Homayoun, Mohammad-Reza
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Golchin, Arash
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Effect of Hygrothermal Ageing on Tribological Behaviour of PTFE-Based Composites2018Ingår i: Lubricants, E-ISSN 2075-4442, Vol. 6, nr 4, artikel-id 103Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present study investigates the influence of hygrothermal ageing on the tribological behaviour of polytetrafluoroethylene (PTFE) polymer composites. Three PTFE composites along with unfilled PTFE were tested in sliding contact against Inconel 625 (a Ni-based alloy) plates in both dry and water-lubricated conditions, utilising a unidirectional pin-on-disc tribometer. The tribo-tests were performed at a constant sliding speed of 0.13 m/s with a normal load of 84N providing an apparent contact pressure of 5 MPa. Hygrothermal conditioning was carried out at two different temperatures, and the water absorption evolution and kinetic parameters were estimated. Various characterisation methods were used to identify the wear mechanisms and influence of hygrothermal ageing on the degradation of the filler/matrix. The different tribological behaviour for different PTFE composites was observed within the ageing timeframe. The wear resistance of the fibre-filled samples was reduced compared to the non-aged ones over the ageing timeframe. However, the friction and wear resistance of the bronze-filled PTFE were enhanced by hygrothermal ageing.

  • 6.
    Emami, Nazanin
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Belotti, Luca
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Effect of surface roughness and hygrothermal aging of multiscale carbon reinforced UHMWPE composites2018Konferensbidrag (Refereegranskat)
  • 7.
    Emami, Nazanin
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Melk, Latifa
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Fracture toughness and thermal characterisation of GO based UHMWPE composites2018Konferensbidrag (Refereegranskat)
  • 8.
    Belotti, Luca
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Vadivel, Hari
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Influence of counter surface topography on the tribological behavior  of  hybrid UHMWPE composites2018Konferensbidrag (Refereegranskat)
  • 9.
    Melk, Latifa
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Mechanical and thermal performances of UHMWPE blended vitamin E reinforced carbon nanoparticle composites2018Ingår i: Composites Part B: Engineering, ISSN 1359-8368, E-ISSN 1879-1069, Vol. 146, s. 20-27Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ultrahigh molecular weight polyethylene (UHMWPE) is a known to be the material of choice for bearing components in joint arthroplasty. However, oxidation wear of UHMWPE components is considered to be a major drawback limiting the lifespan of implants. Vitamin E was considered as a promising antioxidant to prevent long-term oxidation and reduce the wear degradation of UHMWPE material. Nevertheless, there are limited results on the improvements of vitamin E on the mechanical and thermal properties of UHMWPE. In this study, we investigated the incorporation of 0.5–3 wt.% carbon nanoparticles: Multiwalled Carbon Nanotubes (MWCNTs), Graphene (GO) and Nanodiamonds (ND) on the mechanical and thermal properties of UHMWPE blended vitamin E (UHMWPE-E). Surface analysis of the composite powders showed well-dispersed carbon nanoparticles within the UHMWPE-E matrix. Thermogravimetric (TGA) and Differential Scanning Calorimetry (DSC) were used to study the thermal behavior of the nanocomposites. It was found that the addition of GO, MWCNTs and ND improved the thermal stability of the nanocomposites compared to neat UHMWPE-E. However, the addition of carbon nanoparticles had no significant effect on the crystallization parameters of the composites. In addition, the incorporation of MWCNT and ND improved significantly the fracture toughness of the composites. The addition of 0.7 wt.% ND and 1 wt.% MWCNT increased the fracture toughness from 5.93 MPa m1/2 for neat UHMWPE-E to 7.38 and 9.19 MPa m1/2 respectively. The enhanced fracture toughness and thermal stability of the nanocomposites could be due to the successful powder processing technique where an optimized mixing and ball milling parameters were used.

  • 10.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Processing of high performance thermoplastic multiscale composites for tribological applications2018Ingår i: 45th Leeds-Lyon Symposium on Tribology, 2018Konferensbidrag (Refereegranskat)
  • 11.
    Vadivel, Hari
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Golchin, Arash
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Tribological behaviour of carbon filled hybrid UHMWPE composites in water2018Ingår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 124, s. 169-177Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, newly developed hybrid composites with Ultra High Molecular Weight Polyethylene (UHMWPE) as base polymer and Graphene Oxide (GO), Nano Diamonds (ND) and Short Carbon Fibres (SCF) as fillers were manufactured. The tribological performance of these composites in a water lubricated sliding contact and the effect of inclusion of the fillers on the mechanical and thermal properties of the composites were investigated. The resulting hybrid composite formed by using the fillers and the base polymer displayed low friction coefficient and high wear resistance. Compared to unfilled UHMWPE, composite with all the fillers incorporated had 21% smaller friction coefficient and 15% less wear.

  • 12.
    Melk, Latifa
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Tribological, mechanical and thermal performances of UHMWPE blended vitamin E reinforced carbon nano-particle composites2018Konferensbidrag (Refereegranskat)
  • 13.
    Emami, Nazanin
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    McLaren, Heather
    Leeds University, UK.
    Neville, Anne
    Leeds University, UK.
    Bryant, Micheal
    Leeds University, UK.
    Tribological performance of PEEK and a PEEK composite in reciprocating sliding under various conditions2018Konferensbidrag (Refereegranskat)
  • 14.
    Suñer Moreno, Silvia
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Gowland, N.
    Institute of Medical and Biological Engineering, University of Leeds.
    Craven, R.
    Institute of Medical and Biological Engineering, University of Leeds.
    Joffe, Roberts
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Tripper, J.L.
    Institute of Medical and Biological Engineering, University of Leeds.
    Ultrahigh molecular weight polyethylene/graphene oxide nanocomposites: wear characterization and biological response to wear particles2018Ingår i: Journal of Biomedical Materials Research. Part B - Applied biomaterials, ISSN 1552-4973, E-ISSN 1552-4981, Vol. 106, nr 1, s. 183-190Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the field of total joint replacements, polymer nanocomposites are being investigated as alternatives to ultrahigh molecular weight polyethylene (UHMWPE) for acetabular cup bearings. The objective of this study was to investigate the wear performance and biocompatibility of UHMWPE/graphene oxide (GO) nanocomposites. This study revealed that low concentrations of GO nanoparticles (0.5 wt %) do not significantly alter the wear performance of UHMWPE. In contrast, the addition of higher concentrations (2 wt %) led to a significant reduction in wear. In terms of biocompatibility, UHMWPE/GO wear particles did not show any adverse effects on L929 fibroblast and PBMNC viability at any of the concentrations tested over time. Moreover, the addition of GO to a UHMWPE matrix did not significantly affect the inflammatory response to wear particles. Further work is required to optimize the manufacturing processes to improve the mechanical properties of the nanocomposites and additional biocompatibility testing should be performed to understand the potential clinical application of these materials

  • 15.
    Safari, Alaleh
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Cervantes, Michel Jose
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik. Water Power Laboratory , Norwegian University of Science and Technology .
    Viscoelasticity and shear-thinning effects on bio-polymer solution and suspended particle behaviours under oscillatory curve Couette flow conditions2018Ingår i: Biosurface and Biotribology, ISSN 2405-4518, Vol. 4, nr 1, s. 1-17Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Formation of wear particles within total hip replacement is one of the main causes of its failure. In addition to improving the lubrication and wear resistance of materials used as bearing surfaces, understanding of wear particle distribution patterns within lubricants inside an implant gap could be used to improve design parameters and implants’ lifespan. In this study, the behaviours of biolubricants (with compositions similar to human joint synovial fluid) and suspended particles were investigated by micro-particle image velocimetry in curved mini channels under oscillatory Couette flow conditions. The studied biolubricants had shear-thinning viscoelastic characteristics. The authors found that increasing shear-thinning, elasticity or motion frequency levels did not affect the trend behaviours of biolubricant flows due to the low strain values of the experimental conditions applied. However, suspended particles formed strings along flow directions and exhibited cross-stream migration to channel walls. Motion frequency, fluid shear thinning and elasticity characteristics and channel dimensions strongly affected particle behaviours.

  • 16.
    Rodiouchkina, Maria
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Berglund, Kim
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Larsson, Roland
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Dry sliding wear and friction behavior of self-lubricating polymer composite bearing materials under extreme operating conditions2017Konferensbidrag (Refereegranskat)
  • 17.
    Safari, Alaleh
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Espanol, Montserrat
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia.
    Ginebra, Maria-Pau
    Biomaterials, Biomechanics and Tissue Engineering Group, Dept. of Materials Science and Metallurgy, Technical University of Catalonia.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik. Water Power Laboratory, Norwegian University of Science and Technology.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Effect of dynamic loading versus static loading on the frictional behavior of a UHMWPE pin in artificial biolubricants2017Ingår i: Biosurface and Biotribology, ISSN 2405-4518, Vol. 3, nr 1, s. 35-44Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To obtain reliable results from in vitro measurements on the tribological behavior of joint implant materials, the parameters of the measurements must simulate in vivo conditions. Although the nature of the load in human joints is dynamic, most of the studies using simple pin-on-disk tribometers were performed with a constant load. The current study focused on investigating the effect of dynamic loading in comparison with static loading in the tribological behavior of ultra-high-molecular-weight polyethylene (UHMWPE) sliding against a cobalt chromium molybdenum (CoCrMo) counter surface with different lubricants, where the effects of hyaluronic acid (HA) and protein content in the lubricants were also investigated. The results suggested that although the dynamic loading did not affect the friction evolution for any of the lubricants, the friction value decreased for the lubricants that did not contain HA. The results showed that higher protein content in the lubricant increased the friction coefficient, however, it provided the highest protection against wear for sliding surfaces.

  • 18.
    Homayoun, Mohammad Reza
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Effect of hygrothermal aging on wear mechanism and friction behavior of PTFE composites2017Konferensbidrag (Refereegranskat)
  • 19.
    Homayoun, Mohammad reza
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Effect of hygrothermal aging on wear mechanism and friction behavior of PTFE composites2017Konferensbidrag (Refereegranskat)
  • 20.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Effect of hydrothermal ageing on wear mechanism and friction behaviour of PTFE composite2017Ingår i: Effect of hydrothermal ageing on wear mechanism and friction behaviour of PTFE composites, 2017Konferensbidrag (Refereegranskat)
  • 21.
    Jain, Ayush
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    High performance hybrid polymer composites for tribological applications2017Konferensbidrag (Refereegranskat)
  • 22.
    Jain, Ayush
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    High performance hybrid PPS polymeri composites for tribological applications2017Konferensbidrag (Refereegranskat)
  • 23.
    McLaren, Heather
    et al.
    Leeds University, UK.
    Bryant, Micheal
    Leeds University, UK.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Neville, Anne
    Leeds University, UK.
    High-Performance Polymer Composites for Extreme Conditions2017Konferensbidrag (Refereegranskat)
  • 24.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Investigation of the mechanical and the thermal properties of HMWPE-blended vitamin E/nanofillers composites2017Ingår i: The 9thInternational Biotribology Forum. The 9thChinese Biotribology and Implant Engineering Satellite Forum of 6th World Tribology Congress (WTC), 2017Konferensbidrag (Refereegranskat)
  • 25.
    Emami, Nazanin
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Vadivel, Hari
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Tribological behavior of carbon filled hybrid UHMWPE composites in water2017Konferensbidrag (Refereegranskat)
  • 26.
    Golchin, Arash
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Villain, Alexis
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Tribological Behaviour of Nanodiamond Reinforced UHMWPE in Water-Lubricated Contacts2017Ingår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 110, s. 195-200Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, the tribological behaviour of nanodiamond reinforced UHMWPE composites was investigated in water-lubricated sliding contacts. A significant reduction of 72% in wear and 24% in friction of UHMWPE was observed with incorporation of 1 wt% nanodiamond in the polymer matrix. Various bulk and surface characterization techniques were utilised to reveal the main mechanisms involved in the friction and wear response of the polymeric materials. The improved tribological behaviour of UHMWPE upon incorporation of various loadings of nanodiamond in the polymer matrix was mainly attributed to the boundary lubricating action of nanodiamonds and the polishing effect of the nanodiamond reinforced UHMWPE composites on the counter surfaces in water-lubricated sliding contacts.

  • 27.
    Vadivel, Hari
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Golchin, Arash
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Tribological performance and thermal characteristics of UHMWPE multifunctional hybrid composites2017Konferensbidrag (Refereegranskat)
  • 28.
    Golchin, Arash
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Wikner, Alfred
    Luleå University of Technology.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    An Investigation into Tribological Behaviour of Multi-Walled Carbon Nanotube/Graphene Oxide Reinforced UHMWPE in Water Lubricated Contacts2016Ingår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 95, s. 156-161Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, the influence of incorporation of carbon based nano fillers, namely multi-walled carbon nanotubes and graphene oxide on the tribological behaviour of ultra-high molecular weight polyethylene was investigated in water lubricated sliding contacts. Further investigations were carried out to study the influence of γ-irradiation and hygrothermal aging on the friction and wear response of the polymeric materials. It was found that regardless of the treatment, GO/MWNT reinforced composites consistently exhibited a lower friction and higher wear resistance in comparison to the unfilled UHMWPE. This was mainly attributed to the lubricating action of the carbonaceous nano fillers in water lubricated sliding contacts.

  • 29.
    Li, Bin
    et al.
    Department of Mechanical Engineering, Wichita State University.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Gong, Guan
    Swerea SICOMP AB, Box 271, 941 26, Piteå.
    Song, Weidong
    Department of Mechanical Engineering, Wichita State University, PD Materials, Boeing Commercial Airplanes, Seattle, WA 98124.
    Applications of Nanomaterials in Multifunctional Polymer Nanocomposites2016Ingår i: Journal of Nanomaterials, ISSN 1687-4110, E-ISSN 1687-4129, Vol. 2016, artikel-id 5790194Artikel i tidskrift (Övrigt vetenskapligt)
  • 30.
    Safari, Alaleh
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Bio-lubricant Behavior under Reciprocating Motion in Mini-Channel2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    Synovial fluid (SF) is articular joint lubrication. It contains a linear biopolymer called Hyaluronic acid(HA), which causes the viscoelastic behavior. Several studies on viscoelasticity of synovial fluid orHA solutions with different concentration and molecular weight have been carried out withrheometers. However, there are very few studies on the effect of viscoelasticity on HA solutionsmovement and velocity distribution inside the joint gap. Therefore, in this study, HA solutions withdifferent concentrations were studied under a sinusoidal reciprocating movement inside a rectangularmini-channel. This study focuses on deriving velocity distribution along channel width with MicroParticle Image Velocimetry (micro-PIV). Very high viscosity of the HA solutions suggests a quasisteadybehavior for this solution under investigated sinusoidal movement. However, the resultsindicated that the steady state laws are not applicable for estimating the HA behavior because ofspecial polymeric behavior of the HA chains inside the solutions.

  • 31.
    Safari, Alaleh
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Bio-lubricant Behavior under Reciprocating Motion in Mini-Channel2016Konferensbidrag (Refereegranskat)
  • 32.
    Safari, Alaleh
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Bio-lubricant flow behaviour in mini-channels2016Ingår i: Lubrication Science, ISSN 0954-0075, E-ISSN 1557-6833, Vol. 28, nr 4, s. 221-242Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    One of the most common causes of failures in total joint replacements is the generation of wear particles within the joint. This contributes to bone lost and aseptic loosening of the implant, eventually requiring its replacement. Many studies have been carried out to improve the wear characteristics of bearing surfaces in total joint replacement. From the lubrication point of view, the friction behaviour of surfaces and rheology of the joint lubricant (synovial fluid) have been extensively studied. However, little attention has been paid to the interaction between the lubricant and the bearing surfaces. The aim of this study is to develop a methodology for studying the behaviour of bio-based lubricant in mini-channels. For this purpose, micro-particle image velocimetry was used in order to characterise the lubricant behaviour. Channels made of relevant materials such as ultra-high molecular weight polyethylene, cobalt–chromium–molybdenum alloy and titanium–aluminium–vanadium alloy with 1 and 1.5 mm width, 45 mm length and 2 mm depth were experimentally investigated. Results suggested that the used polymeric solution interaction with solid surfaces is very sensitive to the polymer concentration in the lubricant. Moreover, it was observed that there exist differences between water (Newtonian reference fluid) and the polymeric solution behaviour even at very simple movements; although usually, the properties of this lubricant at high shear rates are estimated by water properties.

  • 33.
    Bryant, Micheal
    et al.
    Leeds University, UK.
    Rituerto, Jorge
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Neville, Anne
    Leeds University, UK.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Exploring the oxide reformation kinetics of CoCrMo alloys in simulated body fluids” Oral presentation2016Konferensbidrag (Refereegranskat)
  • 34.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Graphene oxide reinforced UHMWPE composites in Tribological applications2016Konferensbidrag (Refereegranskat)
  • 35.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Improved tribological performance of water lubricated bearings: using hybrid nanodiamond polymeric composites2016Konferensbidrag (Refereegranskat)
  • 36.
    Rituerto, Jorge
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Bryant, Micheal
    Leeds University, UK.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Neville, Anne
    Leeds University, UK.
    Modelling the repassivation kinetics of CoCrMo alloys in simulated body fluids2016Konferensbidrag (Refereegranskat)
  • 37.
    Henriques, Bruno
    et al.
    CESAM & Department of Chemistry, University of Aveiro.
    Gonçalves, Gil
    TEMA-NRD, Mechanical Engineering Department, University of Aveiro, University of Aveiro, Nanotechnology Research Division, University of Aveiro.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Pereira, Eduarda
    CESAM & Department of Chemistry, University of Aveiro.
    Vila, Mercedes
    TEMA-NRD, Mechanical Engineering Department, University of Aveiro.
    Marques, Paula A.P.A.
    TEMA-NRD, Mechanical Engineering Department, University of Aveiro.
    Optimized graphene oxide foam with enhanced performance and high selectivity for mercury removal from water2016Ingår i: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 301, s. 453-461Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work explores the preparation of three-dimensional graphene oxide macroscopic structures, shaped by self-assembling single graphene oxide (3DGO) sheets with control of its surface chemistry by combining with nitrogen functional groups (3DGON), or with nitrogen and sulphur functional groups (3DGOSN), and their application in the removal of mercury (Hg(II)) from aqueous solutions. The chemical structure of the materials was assessed by using different characterization techniques: SEM, XPS and BET. Adsorption studies conducted in Hg(II) contaminated ultra-pure water reveal the enhanced ability of 3DGON for the adsorption of this metal, when compared to the other GO foams. A small dose of 3DGON (10 mg L−1) allows to remove up to 96% of Hg(II) after 24 h of contact time, leading to a residual concentration in solution close to the guideline value for drinking water (1 μg L−1). The ability of this material to adsorb Hg (II) was evaluated relatively to different experimental parameters such as pH, sorbent dose, time and effect on different competing metal ions. Real application was also evaluated by testing its performance in two different natural matrices, river and sea water, with very promising results.

  • 38.
    Almeida, Nuno A.F.
    et al.
    Mechanical Engineering Department & TEMA, University of Aveiro, Campus Universitário de Santiago.
    Rodrigues, Joana
    Physics Department & I3N, University of Aveiro, Campus Universitário de Santiago.
    Silva, Patricia
    Mechanical Engineering Department & TEMA, University of Aveiro, Campus Universitário de Santiago.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Soares, Manuel J.
    Physics Department & I3N, University of Aveiro, Campus Universitário de Santiago.
    Monteiro, Teresa
    Physics Department & I3N, University of Aveiro, Campus Universitário de Santiago.
    Lopes-da-Silva, José A.
    Chemistry Department & QOPNA, University of Aveiro, Campus Universitário de Santiago.
    Marques, Paula A.A.P.
    Mechanical Engineering Department & TEMA, University of Aveiro, Campus Universitário de Santiago.
    Pressure dependent luminescence in titanium dioxide particles modified with europium ions2016Ingår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 234, s. 137-144Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Particles of titanium dioxide were prepared in the presence of europium ions (TiO2:Eu) by a solvothermal method and thermal annealed in air at 500 °C. The spectroscopic properties of TiO2:Eu particles were analyzed indicating that the Eu3+ ions are likely distributed at the surface or near the surface of the titanium dioxide particles. The photoluminescence analysis showed that the intraionic emission was strongly sensitive to reduced pressure conditions, as seen by its absence under vacuum conditions. The ion emission was re-established as soon as the atmosphere was restored. Additionally, the ion integrated emission intensity follows a linearly dependence with pressure in the range of 150 to 800 mbar revealing a high sensitivity to small variations in pressure, which is an unprecedented result. This innovation will allow the study of new technologies in the area of low vacuum sensors where TiO2:Eu may act as the active element of an optical sensor for a pressure device.

  • 39.
    Enqvist, Evelina
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Ramanenka, Dmitrij
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Grácio, José
    TEMA – NRD, Mechanical Engineering Department, University of Aveiro, 3810-193 Aveiro, Portugal. Aveiro Institute of Nanotechnology (AIN).
    Marques, Paula
    TEMA – NRD, Mechanical Engineering Department, University of Aveiro, 3810-193 Aveiro, Portugal. Aveiro Institute of Nanotechnology (AIN).
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    The effect of ball milling time and rotational speed on ultra high molecular weight polyethylene reinforced with multiwalled carbon nanotubes2016Ingår i: Polymer Composites, ISSN 0272-8397, E-ISSN 1548-0569, Vol. 37, nr 4, s. 1128-1136Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ultra high molecular weight polyethylene (UHMWPE) composites reinforced with multiwalled carbon nanotubes (MWCNT) were produced using planetary ball milling. The aim was to develop a more wear resistant composite with increased mechanical properties to be used in stress bearing joints. The manufacturing technique, using ball-milling to incorporate MWCNT into UHMWPE matrix was investigated. The effect of manufacturing parameters such as effect of ball milling time and rotational speed on final composite was analyzed by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), particle size distribution and contact angle measurements. Ball milling as mixing technique for UHMWPE based composites is not a new approach but yet, the effect of time, rotational speed, loading of milling jar and type of ball mill has not been reported properly for UHMWPE. 0.5 and 1 wt% UHMWPE/MWCNTs were manufactured at different rotational speed and mixing time. The results indicate that rotational speed rather than mixing time is important for dispersing MWCNTs

  • 40.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    UHMWPE composites for bearing applications; manufacturing and tribological characterisation2016Konferensbidrag (Refereegranskat)
  • 41.
    Gomez, Alvaro
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Lindström, Kristoffer
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Ultra high molecular weight polyethylene based nano-composite in medical application: thermal, mechanical and tribological properties before and after aging and gamma irradiation2016Konferensbidrag (Refereegranskat)
  • 42.
    Safari, Alaleh
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Viscoelastic behaviour effect of hyaluronic acid on reciprocating flow inside mini-channel2016Ingår i: Lubrication Science, ISSN 0954-0075, E-ISSN 1557-6833, Vol. 28, nr 8, s. 521-544Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    One of the most successful surgeries during the 21st century is total joint replacement (TJR) with material combination of polymer-on-metal (PoM). Despite its success, wear particle generation at the interface of the polymer and metal causes eventually implant loosening. Investigating and understanding the wear particles distribution should help in designing implants with better performances. First step towards characterising wear particle distribution is deriving the lubricant behaviour and velocity distribution inside implant gap. Different hyaluronic acid (HA) solutions were subjected to a sinusoidal movement in straight rectangular channels. The velocity profiles along the channel width were measured with Micro Particle Image Velocimetry. HA solution behaviour was found to be dependent on the concentration. Results showed significant differences between the water (Newtonian) and HA behaviour in unsteady flow. The unsteady behaviour of the lubricant depended strongly on its non-Newtonian viscoelastic behaviour which was due to the time dependent nature of HA solution.

  • 43.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Manufacturing parameters and Tribological characterisation of carbon reinforced UHMWPE composites “in orthopaedic applications2015Konferensbidrag (Refereegranskat)
  • 44.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Manufacturing parameters and Tribological characterisation of carbon reinforced UHMWPE composites-in orthopaedic applications2015Ingår i: International Tribology Conference, 2015Konferensbidrag (Refereegranskat)
  • 45.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Nanoparticle reinforced UHMWPE for orthopaedic applications “parameters affecting the manufacturing process and mechanical properties2015Konferensbidrag (Refereegranskat)
  • 46.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Past, present and future of the polymeric based devices in orthopaedic applications2015Konferensbidrag (Refereegranskat)
  • 47.
    Safari, Alaleh
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Reciprocation Flow Behavior of Bio-Lubricant in Mini-Channels2015Konferensbidrag (Refereegranskat)
  • 48.
    McLaren, Heather
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik. Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Surface functionalisation of MWCNTs to Improve Behaviour of UHMWPE-Based Nanocomposites2015Konferensbidrag (Refereegranskat)
  • 49.
    Moreno, Silvia Suñer
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Joffe, Roberts
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Tipper, Joanne
    Institute of Medical and Biological Engineering, University of Leeds.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Ultra High Molecular Weight Polyethylene/Graphene Oxide Nanocomposites: Thermal, Mechanical and Wettability Characterisation2015Ingår i: Composites Part B: Engineering, ISSN 1359-8368, E-ISSN 1879-1069, Vol. 78, s. 185-191Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Numerous carbon nanostructures have been investigated in the last years due to their excellent mechanical properties. In this work, the effect of the addition of graphene oxide (GO) nanoparticles to UHMWPE and the optimal %wt GO addition were investigated. UHMWPE/GO nanocomposites with different GO wt% contents were prepared and their mechanical, thermal, structural and wettability properties were investigated and compared with virgin UHMWPE. The results showed that the thermal stability, oxidative resistance, mechanical properties and wettability properties of UHMWPE were enhanced due to the addition of GO. UHMWPE/GO materials prepared with up to 0.5 wt% GO exhibited improved characteristics compared to virgin UHMWPE and nanocomposites prepared with higher GO contents.

  • 50.
    Emami, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Biological responses and osteointegration to UHMWPE based nano-composites2014Konferensbidrag (Refereegranskat)
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