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Aysegul Copur-Cicek,Osman Birol Ozgumus,Aysegul Saral,Cemal Sandalli 대한진단검사의학회 2014 Annals of Laboratory Medicine Vol.34 No.2
We aimed to observe antimicrobial resistance patterns and integron carriage of Esche- richia coli isolates causing community-acquired infections. Two hundred sixty-eight E. coli strains were obtained from outpatients with various infections at different polyclinics at the 82nd Year of State Hospital in Rize, Turkey. Susceptibility to antimicrobials was tested us- ing a disk diffusion method. The presence of integrons was examined using PCR with specific primers. Positive PCR results were confirmed by sequencing. A broth mating method was used for conjugation assays. Extragenic palindromic-PCR was performed us- ing the oligonucleotide primer BOXA1R. Resistance frequency for ampicillin, trime- thoprim/sulfamethoxazole, and tetracycline was determined as 50.6%, 33.5%, and 36.8% respectively. No strains were resistant to amikacin. Seventy isolates were positive for the intI1 gene, of which 49 carried gene cassettes. Eleven isolates were positive for the intI2 gene, eight of which carried gene cassettes. Seven gene cassettes ( dfrA1, dfrA5, dfrA7, dfrA17, aadA1, aadA5 , and sat2 ) were predominantly harbored in integrons. We detected conjugative plasmids harboring integrons in two E. coli strains. Four strain clus- ters were yielded by BOX-PCR fingerprints showing that they were clonally related. No ap- parent relationship occurred among class 1 and 2 integron-carrying strains. We conclude that integrons are widespread in genetically variable E. coli strains and will continue to mediate dissemination of resistance genes in the community.
Flexural behaviour of square UHPC-filled hollow steel section beams
Guler, Soner,Copur, Alperen,Aydogan, Metin Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.43 No.2
This paper presents an experimental investigation of the flexural behavior of square hollow steel section (HSS) beams subjected to pure bending. Totally six unfilled and nine ultra high performance concrete (UHPC)-filled HSS beams were tested under four-point bending until failure. The effects of the steel tube thickness, the yield strength of the steel tube and the strength of concrete on moment capacity, curvature, and ductility of UHPC-filled HSS beams were examined. The performance indices named relative ductility index (RDI) and strength increasing factor (SIF) were investigated with regard to different height-to-thickness ratio of the specimens. The flexural strengths obtained from the tests were compared with the values predicted by Eurocode 4, AISC-LRFD and CIDECT design codes. The results showed that the increase in the moment capacity and the corresponding curvature is much greater for thinner HSS beams than thicker ones. Eurocode 4 and AISC-LRFD predict the ultimate moment capacity of the all UHPC-filled HSS beams conservatively.
Mehtap Ozekmekci,Derya Unlu,Mehmet Copur 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.9
Removal of boron from water is a significant issue worldwide. Boron levels in waters containing high concentrations should be kept under control. Boron removal from the industrial wastewater released from Eti Mine Boron plants was investigated by using blend and hybrid membranes in a laboratory-scale pervaporation system. Polyvinylpyrrolidone/ Polyvinylidene fluoride blend membrane and Graphene oxide/Polyvinylpyrrolidone/Polyvinylidene fluoride hybrid membranes were synthesized for this process. The membranes were characterized by using scanning electron microscopy, Fourier transform infrared, X-ray diffraction and contact angle measurements. Separation performance was evaluated in terms of flux, removal ratio of boron, and boron concentration in permeate within the membrane. Membranes showed higher separation performance in industrial wastewater. The highest boron removal was obtained as 99.86% with a flux of 0.755 kg/m2h when the 8wt% graphene oxide loaded hybrid membrane was used. This study indicates that the Polyvinylpyrrolidone and Graphene oxide addition improved the membrane features and separation performances of the pervaporation process with improved hydrophilic membrane features can be preferred as an innovative water treatment method for the removal of boron from industrial wastewater. The obtained results show that pervaporation can be readily adapted to the removal of boron species by appropriate membrane selection.