mustafa urgen | Istanbul Technical University (original) (raw)

Papers by mustafa urgen

Birbirleri ile temas halinde olan yuzeylerden, mekanik etkilerle olusan malzeme kaybi, yuzyillard... more Birbirleri ile temas halinde olan yuzeylerden, mekanik etkilerle olusan malzeme kaybi, yuzyillardir insanoglunun mekanik problemlerinin basinda gelmistir. Dunyadaki mekanik enerjinin yuzde otuzunun mekanik kayiplara harcandigi dusunulurse, surtunme ve asinmanin onemi daha da iyi anlasilabilir. Teknolojik ilerlemelerle birlikte surtunme ve bunun neden oldugu asinma problemlerinin asilmasi icin sert yuzey kaplamalari kullanilmistir. TiN, CrN gibi ince film kaplamalar endustriyel uygulamalar icin en yaygin olarak kullanilan kaplamalardir. Molibden esasli nitrur kaplamalarda, surtunme ve asinma acisindan oldukca ustun ozelliklere sahiptirler. Molibden esasli kaplamalar da dusuk surtunme katsayisi elde edilmesine ragmen temel problem, karsit malzemede meydana gelen asinmadir. Cok sert olan molibden kaplamlara yumusak Ag, Cu gibi elementlerin ilavesi ile elde edilen yapilar, kuru sartlarda ticari olarak kullanilan kaplamalardan daha ustun surtunme-asinma ozelliklerine sahiptirler. Bu cali...

Journal of Tribology, 2010

Wear characteristics of Al6061 composites, reinforced with short NiTi fibers, were investigated. ... more Wear characteristics of Al6061 composites, reinforced with short NiTi fibers, were investigated. The NiTi/Al6061 composite samples were fabricated using pressure-assisted sintering process in ambient air where the NiTi fibers are aligned unidirectional in the Al matrix. In addition, NiTi/Al6061 composite with 5 wt % SiC particulates and monolithic Al6061 and Al6061 with 5 wt % SiC particulates were processed in similar conditions. The wear tests were performed using a reciprocating tribometer in ball-on-flat configuration where the counterbody material was martensitic steel. The effects of fiber isotropy and SiC reinforcements on wear resistance were experimentally investigated in dry sliding. Wear properties of the samples were studied using an optical profiler and a scanning electron microscope analysis. The results showed that transverse NiTi fibers improve the wear resistance significantly. Samples with transverse fiber orientation show mostly abrasive wear, whereas, monolithic ...

Materials science & engineering. C, Materials for biological applications, 2019

Bacterial infection is a serious medical problem leading to implant failure. The current antibiot... more Bacterial infection is a serious medical problem leading to implant failure. The current antibiotic based therapies rise concerns due to bacterial resistance. The family of antimicrobial peptides (AMP) is one of the promising candidates as local therapy agents due to their broad-spectrum activity. Despite AMPs receive increasing attention to treat infection, their effective delivery to the implantation site has been limited. Here, we developed an engineered dual functional peptide which delivers AMP as a biomolecular therapeutic agent onto calcium phosphate (Ca-P) deposited nanotubular titanium surfaces. Dual functionality of the peptide was achieved by combining a hydroxyapatite binding peptide-1 (HABP1) with an AMP using a flexible linker. HABP functionality of the peptide provided a self-coating property onto the nano-topographies that are designed to improve osteointegration capability, while AMP offered an antimicrobial protection onto the implant surface. We successfully depos...

Materials Science and Engineering: C, 2009

Phage display is a commonly utilized in vivo approach in selecting peptides specific to solid ino... more Phage display is a commonly utilized in vivo approach in selecting peptides specific to solid inorganic materials. In this process, traditionally, high affinity peptides are recovered by a chemical elution method, which involves contacting the phage library with the desired inorganic, washing the weak binders, and eluting the tight binders under harsh buffer conditions. This process may result in incomplete

BioMed Research International, 2015

Mixed-phaseTiO2nanocomposite thin films consisting of anatase and rutile prepared on commercially... more Mixed-phaseTiO2nanocomposite thin films consisting of anatase and rutile prepared on commercially pure Ti sheets via the electrochemical anodization and annealing treatments were investigated in terms of their photocatalytic activity for antibacterial use around dental implants. The resulting films were characterized by scanning electron microscopy (SEM), and X-ray diffraction (XRD). The topology was assessed by White Light Optical Profiling (WLOP) in the Vertical Scanning Interferometer (VSI) mode. Representative height descriptive parameters of roughnessRaandRzwere calculated. The photocatalytic activity of the resultingTiO2films was evaluated by the photodegradation of Rhodamine B (RhB) dye solution. The antibacterial ability of the photocatalyst was examined by Aggregatibacter actinomycetemcomitanssuspensions in a colony-forming assay. XRD showed that anatase/rutile mixed-phaseTiO2thin films were predominantly in anatase and rutile that were 54.6 wt% and 41.9 wt%, respectively....

Bioinorganic Chemistry and Applications, 2014

It is important to develop functional transmucosal implant surfaces that reduce the number of ini... more It is important to develop functional transmucosal implant surfaces that reduce the number of initially adhering bacteria and they need to be modified to improve the anti-bacterial performance. Commercially pure Ti sheets were anodized in an electrolyte containing ethylene glycol, distilled water and ammonium fluoride at room temperature to produce TiO 2 nanotubes. These structures were then annealed at 450 ∘ C to transform them to anatase. As-annealed TiO 2 nanotubes were then treated in an electrolyte containing 80.7 g/L NiSO 4 ⋅7H 2 O, 41 g/L MgSO 4 ⋅7H 2 O, 45 g/L H 3 BO 3 , and 1.44 g/L Ag 2 SO 4 at 20 ∘ C by the application of 9 V AC voltage for doping them with silver. As-annealed TiO 2 nanotubes and as-annealed Ag doped TiO 2 nanotubes were evaluated by SEM, FESEM, and XRD. Antibacterial activity was assessed by determining the adherence of A. actinomycetemcomitans, T. forsythia, and C. rectus to the surface of the nanotubes. Bacterial morphology was examined using an SEM. As-annealed Ag doped TiO 2 nanotubes revealed intense peak of Ag. Bacterial death against the as-annealed Ag doped TiO 2 nanotubes were detected against A. actinomycetemcomitans, T. forsythia, and C. rectus indicating antibacterial efficacy.

Surface & Coatings Technology, 2003

Molybdenum nitride coatings were deposited onto H13 hot working tool steel and alumina substrates... more Molybdenum nitride coatings were deposited onto H13 hot working tool steel and alumina substrates by arc PVD. The coatings were characterized with respect to their mechanical and structural properties. Oxidation behavior of the coatings on alumina substrates was investigated by TG/DTA. Coated H13 substrates were oxidized in a tube furnace under atmospheric conditions at specific temperatures determined from TG/DTA tests

Applied Surface Science, 2009

Surface & Coatings Technology, 2010

In this study, we introduce a rapid boriding technique that can produce very thick titanium dibor... more In this study, we introduce a rapid boriding technique that can produce very thick titanium diboride (TiB2) layers on titanium substrates. We also discuss the effects of process duration on boride layer thickness, chemistry and, morphology. In our experiments, the boriding of commercial purity titanium (CP-Ti) substrates was carried out in an electrochemical cell in which we used a mixture

Surface & Coatings Technology, 2010

In this study, we introduce a rapid boriding technique that can produce very thick titanium dibor... more In this study, we introduce a rapid boriding technique that can produce very thick titanium diboride (TiB2) layers on titanium substrates. We also discuss the effects of process duration on boride layer thickness, chemistry and, morphology. In our experiments, the boriding of commercial purity titanium (CP-Ti) substrates was carried out in an electrochemical cell in which we used a mixture

Surface & Coatings Technology, 2009

CrN, Cr–O–N and Cr–O coatings with different oxygen contents were produced with reactive cathodic... more CrN, Cr–O–N and Cr–O coatings with different oxygen contents were produced with reactive cathodic arc physical vapor deposition on high speed steel substrates. The temperature dependent friction and wear behaviours of these coatings were investigated within the temperature range of 25–100 °C. The results of the study showed that it is possible to produce CrN coatings with temperature independent, low coefficient

Quality Engineering, 1999

ABSTRACT terms-and-conditions-of-access.pdf This article may be used for research, teaching and p... more ABSTRACT terms-and-conditions-of-access.pdf This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.

Birbirleri ile temas halinde olan yuzeylerden, mekanik etkilerle olusan malzeme kaybi, yuzyillard... more Birbirleri ile temas halinde olan yuzeylerden, mekanik etkilerle olusan malzeme kaybi, yuzyillardir insanoglunun mekanik problemlerinin basinda gelmistir. Dunyadaki mekanik enerjinin yuzde otuzunun mekanik kayiplara harcandigi dusunulurse, surtunme ve asinmanin onemi daha da iyi anlasilabilir. Teknolojik ilerlemelerle birlikte surtunme ve bunun neden oldugu asinma problemlerinin asilmasi icin sert yuzey kaplamalari kullanilmistir. TiN, CrN gibi ince film kaplamalar endustriyel uygulamalar icin en yaygin olarak kullanilan kaplamalardir. Molibden esasli nitrur kaplamalarda, surtunme ve asinma acisindan oldukca ustun ozelliklere sahiptirler. Molibden esasli kaplamalar da dusuk surtunme katsayisi elde edilmesine ragmen temel problem, karsit malzemede meydana gelen asinmadir. Cok sert olan molibden kaplamlara yumusak Ag, Cu gibi elementlerin ilavesi ile elde edilen yapilar, kuru sartlarda ticari olarak kullanilan kaplamalardan daha ustun surtunme-asinma ozelliklerine sahiptirler. Bu cali...

Journal of Tribology, 2010

Wear characteristics of Al6061 composites, reinforced with short NiTi fibers, were investigated. ... more Wear characteristics of Al6061 composites, reinforced with short NiTi fibers, were investigated. The NiTi/Al6061 composite samples were fabricated using pressure-assisted sintering process in ambient air where the NiTi fibers are aligned unidirectional in the Al matrix. In addition, NiTi/Al6061 composite with 5 wt % SiC particulates and monolithic Al6061 and Al6061 with 5 wt % SiC particulates were processed in similar conditions. The wear tests were performed using a reciprocating tribometer in ball-on-flat configuration where the counterbody material was martensitic steel. The effects of fiber isotropy and SiC reinforcements on wear resistance were experimentally investigated in dry sliding. Wear properties of the samples were studied using an optical profiler and a scanning electron microscope analysis. The results showed that transverse NiTi fibers improve the wear resistance significantly. Samples with transverse fiber orientation show mostly abrasive wear, whereas, monolithic ...

Materials science & engineering. C, Materials for biological applications, 2019

Bacterial infection is a serious medical problem leading to implant failure. The current antibiot... more Bacterial infection is a serious medical problem leading to implant failure. The current antibiotic based therapies rise concerns due to bacterial resistance. The family of antimicrobial peptides (AMP) is one of the promising candidates as local therapy agents due to their broad-spectrum activity. Despite AMPs receive increasing attention to treat infection, their effective delivery to the implantation site has been limited. Here, we developed an engineered dual functional peptide which delivers AMP as a biomolecular therapeutic agent onto calcium phosphate (Ca-P) deposited nanotubular titanium surfaces. Dual functionality of the peptide was achieved by combining a hydroxyapatite binding peptide-1 (HABP1) with an AMP using a flexible linker. HABP functionality of the peptide provided a self-coating property onto the nano-topographies that are designed to improve osteointegration capability, while AMP offered an antimicrobial protection onto the implant surface. We successfully depos...

Materials Science and Engineering: C, 2009

Phage display is a commonly utilized in vivo approach in selecting peptides specific to solid ino... more Phage display is a commonly utilized in vivo approach in selecting peptides specific to solid inorganic materials. In this process, traditionally, high affinity peptides are recovered by a chemical elution method, which involves contacting the phage library with the desired inorganic, washing the weak binders, and eluting the tight binders under harsh buffer conditions. This process may result in incomplete

BioMed Research International, 2015

Mixed-phaseTiO2nanocomposite thin films consisting of anatase and rutile prepared on commercially... more Mixed-phaseTiO2nanocomposite thin films consisting of anatase and rutile prepared on commercially pure Ti sheets via the electrochemical anodization and annealing treatments were investigated in terms of their photocatalytic activity for antibacterial use around dental implants. The resulting films were characterized by scanning electron microscopy (SEM), and X-ray diffraction (XRD). The topology was assessed by White Light Optical Profiling (WLOP) in the Vertical Scanning Interferometer (VSI) mode. Representative height descriptive parameters of roughnessRaandRzwere calculated. The photocatalytic activity of the resultingTiO2films was evaluated by the photodegradation of Rhodamine B (RhB) dye solution. The antibacterial ability of the photocatalyst was examined by Aggregatibacter actinomycetemcomitanssuspensions in a colony-forming assay. XRD showed that anatase/rutile mixed-phaseTiO2thin films were predominantly in anatase and rutile that were 54.6 wt% and 41.9 wt%, respectively....

Bioinorganic Chemistry and Applications, 2014

It is important to develop functional transmucosal implant surfaces that reduce the number of ini... more It is important to develop functional transmucosal implant surfaces that reduce the number of initially adhering bacteria and they need to be modified to improve the anti-bacterial performance. Commercially pure Ti sheets were anodized in an electrolyte containing ethylene glycol, distilled water and ammonium fluoride at room temperature to produce TiO 2 nanotubes. These structures were then annealed at 450 ∘ C to transform them to anatase. As-annealed TiO 2 nanotubes were then treated in an electrolyte containing 80.7 g/L NiSO 4 ⋅7H 2 O, 41 g/L MgSO 4 ⋅7H 2 O, 45 g/L H 3 BO 3 , and 1.44 g/L Ag 2 SO 4 at 20 ∘ C by the application of 9 V AC voltage for doping them with silver. As-annealed TiO 2 nanotubes and as-annealed Ag doped TiO 2 nanotubes were evaluated by SEM, FESEM, and XRD. Antibacterial activity was assessed by determining the adherence of A. actinomycetemcomitans, T. forsythia, and C. rectus to the surface of the nanotubes. Bacterial morphology was examined using an SEM. As-annealed Ag doped TiO 2 nanotubes revealed intense peak of Ag. Bacterial death against the as-annealed Ag doped TiO 2 nanotubes were detected against A. actinomycetemcomitans, T. forsythia, and C. rectus indicating antibacterial efficacy.

Surface & Coatings Technology, 2003

Molybdenum nitride coatings were deposited onto H13 hot working tool steel and alumina substrates... more Molybdenum nitride coatings were deposited onto H13 hot working tool steel and alumina substrates by arc PVD. The coatings were characterized with respect to their mechanical and structural properties. Oxidation behavior of the coatings on alumina substrates was investigated by TG/DTA. Coated H13 substrates were oxidized in a tube furnace under atmospheric conditions at specific temperatures determined from TG/DTA tests

Applied Surface Science, 2009

Surface & Coatings Technology, 2010

In this study, we introduce a rapid boriding technique that can produce very thick titanium dibor... more In this study, we introduce a rapid boriding technique that can produce very thick titanium diboride (TiB2) layers on titanium substrates. We also discuss the effects of process duration on boride layer thickness, chemistry and, morphology. In our experiments, the boriding of commercial purity titanium (CP-Ti) substrates was carried out in an electrochemical cell in which we used a mixture

Surface & Coatings Technology, 2010

In this study, we introduce a rapid boriding technique that can produce very thick titanium dibor... more In this study, we introduce a rapid boriding technique that can produce very thick titanium diboride (TiB2) layers on titanium substrates. We also discuss the effects of process duration on boride layer thickness, chemistry and, morphology. In our experiments, the boriding of commercial purity titanium (CP-Ti) substrates was carried out in an electrochemical cell in which we used a mixture

Surface & Coatings Technology, 2009

CrN, Cr–O–N and Cr–O coatings with different oxygen contents were produced with reactive cathodic... more CrN, Cr–O–N and Cr–O coatings with different oxygen contents were produced with reactive cathodic arc physical vapor deposition on high speed steel substrates. The temperature dependent friction and wear behaviours of these coatings were investigated within the temperature range of 25–100 °C. The results of the study showed that it is possible to produce CrN coatings with temperature independent, low coefficient

Quality Engineering, 1999

ABSTRACT terms-and-conditions-of-access.pdf This article may be used for research, teaching and p... more ABSTRACT terms-and-conditions-of-access.pdf This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.