Identification of enterobacteriaceae in Urfa cheese

The purpose of this study was to determine the Enterobacteriaceae counts and to identify the species isolated in Urfa cheese traditionally manufactured from raw milk in Sanliurfa. In the research, 75 samples obtained from retail markets were examined. Enterobacteriaceae was detected in 45.33% of the samples and counts varied between 102–108 CFU g−1. A total of 8 different species were identified, the most common of those was Klebsiella pneumonia (30% of the isolated strains), followed by Escherichia coli (25.29%), Enterobacter cloacea (16.47%) and Enterobacter aerogenes (11.76%). Klebsiella oxytoca , Citrobacter freundii, Yersinia enterocolitica and Serratia marcescens were present in small quantities (7.06, 5.88, 2.45 and 1.18% of the isolates, respectively). The results obtained from this study clearly indicate that measures should be taken to control and reduce the contamination and multiplication of pathogens such as E. coli, Y. enterocolitica and other Enterobacteriaceae spp. in Urfa cheese

Improvement of Mechanical Characteristics and Performances with Ni Diffusion Mechanism Throughout Bi-2223 Superconducting Matrix

This study is interested in the role of diffusion annealing temperature (650-850 degrees C) on the mechanical characteristics and performance of pure and Ni diffused Bi-2223 superconducting materials by means of standard compression tests and Vickers hardness measurements at performed different applied loads in the range of 0.245-2.940N and theoretical calculations. Based on the experimental findings, the mechanical performances improve with increasing annealing temperature up to 700 degrees C beyond which they degrade drastically due to the increased artificial disorders, cracks and irregular grain orientation distribution. In other words, the penetration of excess Ni inclusions accelerates both the dislocation movement and especially the cracks and voids propagation as a result of the decrement in the Griffith critical crack length. Further, it is to be mentioned here that all the sample exhibit typical indentation size effect (ISE) behavior. In this respect, both the plastic (irreversible) and elastic (reversible) deformations have dominant role on the superconducting structures as a result of the enhancement in the elastic recovery. At the same time elastic modulus, yield strength and fracture toughness parameters are theoretically extracted from the microhardness values. Moreover, the elastic modulus parameters are compared with the experimental values. It is found that the differentiation between the comparison results enhances hastily with the increment in the applied indentation test loads due to the existence of the increased permanent disorders, lattice defects and strains in the stacked layers. Namely, the error level increases away from the actual crystal structure. Additionally, the microhardness values are theoretically analyzed for the change of the mechanical behaviors with the aid of Meyer's law, elastic/plastic deformation and Hays-Kendall approaches for the first time

Experimental and theoretical approaches on mechanical evaluation of Y123 system by Lu addition

Turkoz, Mustafa Burak/0000-0002-4127-7650; Yildirim, Gurcan/0000-0002-5177-3703; Ozturk, Ozgur/0000-0002-0391-5551WOS: 000321913000034This work is the continuation of a systematic study on the characterization of the Lu-added Y123 bulk superconducting materials prepared by the nitrate compounds and derivatives at 970 degrees C for 20 h. In this part, the effect of Lu inclusions on the physical and mechanical properties of the Y123 superconductors is examined with the aid of microhardness measurements performed at various applied loads in the range of 0.245-2.940 N. The microhardness measurement results allow us to determine the important mechanical characteristics such as Vickers microhardness, elastic (Young's) modulus, yield strength and fracture toughness values being responsible for the potential industrial applications. It is found that all the properties given above are strongly dependent upon the Lu concentration in the Y123 matrix. Especially, Vickers microhardness (H-nu) values of the samples studied in this work are found to suppressed considerably with the enhancement of the Lu addition in the system due to the degradation in the connectivity between superconducting grains. Moreover, the H-nu values of the pure Y123 sample are observed to increase with increasing the applied load whereas those of the Lu-doped superconducting materials are obtained to decrease with the load. In other words, the pure sample exhibits the reverse indentation size effect (RISE) behavior while the others obey the indentation size effect (ISE) feature, confirming the degradation in the mechanical properties with the Lu inclusions in the Y123 matrix. In addition, the microhardness measurement results are estimated using the 5 different models such as Meyer's law, proportional sample resistance model, elastic/plastic deformation model, Hays-Kendall (HK) approach and indentation-induced cracking (IIC) model. According to the results obtained from the simulations, of the mechanical analysis models, the Hays-Kendall (HK) approach is determined as the most successful model for the description of the mechanical properties of the Lu-doped superconducting materials (exhibiting the ISE behavior) where both the both the reversible (elastic) and irreversible (plastic) deformations are produced. On the other hand, the IIC model is found to be superior to other approaches for the pure sample (presenting the RISE feature) where the irreversible deformation becomes more and more dominant compared to the reversible deformation