Microstructural Characterization of Co-Based ODS Alloys

Co-based ODS alloys, strengthened by nanosized oxide dispersion and γ′ precipitates, are potential high-temperature structural materials. The characteristics of the mechanically alloyed powder and the microstructural evolution of the Co-based ODS alloys were investigated. The results revealed that mechanical alloying had induced the formation of supersaturated solid solution in immiscible Co-Al-W-based alloys, originating mainly from extensive grain boundary region, high dislocation density, and ample point defect. Chemical compositions of mechanically alloyed Co-Al-W-based ODS alloys easily deviate from the γ/γ′ two-phase region, leading to the existence of Al _x Co, Co₃W, Co₇W₆, and W phases in addition to the γ and γ′ phases. Nonuniform distribution of alloying elements brings about the differences in morphologies and sizes of γ′ precipitates. Microstructural formation process is impelled by spinodal decomposition mode, and spinodal decomposition behavior has been accelerated in the fine-grained alloy because of the presence of short-circuited diffusion paths for atomic movement.     

Amine-functionalized sol-gel-based lab-in-a-pipet-tip approach for the fast enrichment and specific purification of phosphopeptides in MALDI-MS applications

Amine-functionalized sol-gels were investigated for the enrichment and purification of phosphopeptides from digested protein mixture solutions. Tetramethylorthosilicate (TMOS) and N'[3-(trimethoxysilyl)-propyl]-diethylenetriamine (TPDA) were used in a 1:1 mole ratio in the production of amine-functionalized sol-gels. The sol-gel network was then used for phosphopeptide enrichment. Phosphopeptide enrichment onto the synthesized amine-functionalized sol-gels was performed using an enolase digested peptide mixture, a β-casein digested peptide mixture, as well as these digested peptide mixtures contaminated 50-fold with bovine serum albumin (BSA). Moreover, phosphopeptide enrichment was successfully performed using nonfat milk as a highly contaminated and complex material. In each phosphopeptide enrichment and purification process, only phosphopeptides were enriched and separated from the other digested peptides. Phosphopeptides were adsorbed onto the amine-functionalized sol-gels at pH 4.0 and eluted at pH 1.0 using trifluoroacetic acid (TFA). For phosphopeptide analysis by MALDI-MS, a 2,5-dihydroxybenzoic acid matrix containing 1.0% phosphoric acid was used to overcome the degradation of phosphopeptides and provide high intensity phosphopeptide protonated molecular ion signal intensities. It was also found that phosphopeptide detection limits were improved to approximately 10 femtomoles. For rapid and specific phosphopeptide enrichment and purification, sol-gel materials were placed in a 10 μL pipet tip with glass wool on either side. Phosphopeptide enrichment from digested peptide mixtures was performed in a very short time (less than 1 min) at subpicomole levels using this novel lab-in-a-pipet-tip approach.     

Radioactivity levels in some sediment samples from Red Sea and Baltic Sea

Levels of 22?,22?Ra, 232Th, 21?Pb, 21?Po and ??K in sediments from four monitoring areas, El Hamraween and Ras El Behar (Red Sea, Egypt) and LL3A and JML (Baltic Sea, Finland), have been investigated using alpha and gamma spectrometry. The average activity concentrations were 238±4 Bq kg?1 (22?Ra), 215±11 Bq kg?1 (21?Pb) and 311±18 Bq kg?1 (21?Po) for El Hamraween area. In Ras El Behar area, the corresponding values were 16±0.4, 18±1 and 20±5 Bq kg?1, respectively. The activity concentrations for 22?Ra, 21?Pb and 21?Po (uranium series) in El Hamraween bottom sediment are much high compared with those in Ras El Behar area, which indicates the enhanced levels due to the activities of phosphate mining and shipment operations in El Hamraween area. Excluding the influence of phosphate mining activities, it can be concluded that the levels of radioactivity in Baltic Sea sediments are higher than those in Red Sea sediments.     

Re-realization of the NIS National Viscosity Scale and Its Range Extension up to 250,142?mm2/s

A wide-range viscosity standard system has generally been realized with capillary viscometers, which are calibrated by the stepping-up method on the basis of viscosity value of distilled water at 20?°C. As per recommendation of Bureau International des Poids et Mesures (BIPM), the national primary viscosity scale must be realized every 10?years. The present work is an attempt to re-realize the existing scale and extend it to from 70,000 to 250,142?mm²/s. This would enable NIS to calibrate different types of viscometers with the highest constant. The NIS viscosity scale was first realized in 2001 [1] using glass capillary viscometers in the range from 1 to 70,000?mm²/s. From the present calibration results of the NIS viscometers, the present scale is realized with an uncertainty of about 0.07?% at low viscosities (0.9?mm²/s) rising to about 0.25?% at higher viscosities (250,142?mm²/s).     

Preconcentration and matrix elimination for the determination of Pb(II), Cd(II), Ni(II), and Co(II)by 8‐hydroxyquinoline anchored poly(styrene‐divinylbenzene) microbeads

Poly(styrene-divinylbenzene), PS-DVB, microbeads were modified with 8-hydroxyquinoline (8-HQ) following nitration, reduction of  NO₂ to NH₂, and conversion of NH₂ to diazonium salt. Characterization of pristine,  NO₂,  NH₂,  NN⁺Cl⁻, and 8-QH functional groups modified microbeads was made by Fourier transform-infrared spectrometry (FTIR) and porosimetry. Total reflectron-X-ray florescence spectrometer (TXRF) was used to test the affinity of the 8-HQ modified microbeads to toxic metal ions. 8-HQ-modified microbeads were used to examine the adsorption capacity, recovery, preconcentration, and the matrix elimination efficiency for Pb(II), Cd(II), Ni(II), and Co(II) ions as a function of changing pH, initial metal-ion concentrations, and also equilibrium adsorption time of the studied metal ions. Preconcentration factors for the studied toxic metal ions were found to be more than 500-fold and recovery between 93.8% and 100.6%. Ultratrace toxic metal-ion concentrations in sea water were determined easily by using modified microbeads. Reference sea-water sample was used for the validation of the method, and it was found that recovery, preconcentration, and the matrix elimination were performed perfectly. For the desorption of the toxic metal ions, 3M of HNO₃ was used and desorption ratio shown to be more than 96%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Estimation of strength and deformation properties of Quaternary caliche deposits

The aim of this study was to develop and evaluate statistical models for predicting the uniaxial compressive strength (UCS) and average Young’s modulus (E _av) for caliches, using some index and physical properties. The caliche samples, from Adana, southern Turkey, were of low strength and difficult to sample. X-ray diffraction and microscopy were undertaken and the following physical parameters established: unit weight, apparent porosity, Schmidt rebound number, Shore hardness, P-wave velocity, slake durability, point load, uniaxial compressive strength and average Young’s modulus. Simple and linear regression variable selection analyses were performed. The best relationships were obtained for UCS with P-wave velocity and unit weight and for average Young’s modulus with P-wave velocity, porosity and slake durability. Empirical equations are proposed, although it is emphasised that these may only be applicable for caliche of a similar geological character.      

Modelling of bacterial growth with shifts in temperature using automated methods with Listeria monocytogenes and Pseudomonas aeruginosa as examples

Time to detection (TTD) measurements using turbidometry allow a straightforward method for the measurement of bacterial growth rates under isothermal conditions. Growth rate measurements were carried out for Listeria monocytogenes at 25, 30 and 37°C and for Pseudomonas aeruginosa over the temperature range 25 to 45°C. The classical three-parameter logistic model was rearranged to provide the theoretical foundation for the observed TTD. A model was subsequently developed for the analysis of TTD data from non-isothermal studies based on the Malthusian approximation of the logistic model. The model was able to predict the TTD for cultures of L. monocytogenes or P. aeruginosa undergoing simple temperature shunts (e.g. 25 to 37°C and vice versa), and for a multiple temperature shunt for L. monocytogenes (25-37-25-37°C and 37-25-37-25°C) over a period of 24h. In no case did a temperature shunt induce a lag.     

Molecular characterization of mulberry (Morus spp.) genotypes via RAPD and ISSR

BACKGROUND: In recent years, DNA‐based markers have been used quite extensively because of their many advantages over the traditional morphological and biochemical markers. Many studies have shown that molecular markers are useful in delineating the genetic relationships among closely related mulberry genotypes and cultivars. Thus, in the present study, polymer chain reaction based DNA fingerprinting techniques were used to investigate the genetic relationships among mulberry genotypes growing in different agro‐climatic regions of Turkey. RESULTS: 20 RAPD primers generated a total of 173 bands, of which 157 (90.75%) were polymorphic. As for 11 ISSR primers, 124 bands (96.55%) were polymorphic in a total of 128. The similarity index for RAPD technique ranged between 0.24–0.98; 25?s203 with 25?s112 were found to be the closest genotypes, while 24Ke10 and 25?s123 were the most distant ones. According to the ISSR result, the genetic similarity index changed between 0.21–095; 25?s203 with 25?s112 genotypes were the closest, while 25?s08 and 01KaD2 were the most distant ones. CONCLUSION: The RAPD and ISSR markers were found to be promising for assessing genetic diversity in mulberry genotypes. Copyright © 2011 Society of Chemical Industry     

Dynamic Stiffness and Damping of a Shallow Foundation from Forced Vibration of a Field Test Structure

Foundation impedance ordinates are identified from forced vibration tests conducted on a large-scale model test structure in Garner Valley, California. The structure is a steel moment frame with removable cross-bracing, a reinforced concrete roof, and a nonembedded square slab resting on Holocene silty sands. Low-amplitude vibration is applied across the frequency range of 5–15?Hz with a uniaxial shaker mounted on the roof slab. We describe procedures for calculating frequency-dependent foundation stiffness and damping for horizontal translational and rotational vibration modes. We apply the procedures to test data obtained with the structure in its braced and unbraced configurations. Experimental stiffness ordinates exhibit negligible frequency dependence in translation but significant reductions with frequency in rotation. Damping increases strongly with frequency, is stronger in translation than in rocking, and demonstrates contributions from both radiation and hysteretic sources. The impedance ordinates are generally consistent with numerical models for a surface foundation on a half-space, providing that soil moduli are modestly increased from free-field values to account for structural weight, and hysteretic soil damping is considered.