Quality control of coins mint using PIXE and RBS analysis

PIXE and RBS analysis is used to investigate the elemental content of modern Lebanese coins, in order to control their minting quality. The coins of interest were 100, 250 and 500 Lebanese Lira (LL), which are mainly bulky metals with or without coated layer. Using 3 MeV protons, proton induced X-ray emission PIXE identified and quantified elements while Rutherford backscattering spectrometry RBS checked the thickness of the coated layer. Indeed, the combination of PIXE and RBS provides a powerful tool to investigate the elemental composition of coins, either modern or ancient. In addition, the experimental protocol was checked by analyzing some other coins of known composition, such as 1-euro and 2-euro.     

Effect of Ce Substitution on the Properties of Tl-Based Superconductors

Samples with nominal composition (Tl _0.5 Pb _0.5 )Sr _2–x Ce _x Ca ₂ Cu ₃ O _y were prepared with x in the range 0 to 0.5, to investigate the role of charge carrier concentration on the superconducting properties of Tl-based materials. The behavior of the normal state resistivity with temperature showed that as x changes from 0 to 0.2, the material moves towards optimally doped state. For higher Ce content the normal state resistivity versus temperature, started deviating from linearity. The onset transition temperature increased gradually by about 6 K as x was increased from 0 to 0.2. The zero resistance transition temperature rapidly decreased for samples with x > 0.2. Furthermore, XRD analysis revealed that Ce enters the structure of both Tl-1223 and Tl1212. These results are discussed in terms of controlling the hole concentration in the CuO ₂ planes through Ce ⁴⁺ replacement of Sr ²⁺ .     

Modelling of unbounded media for fluid-structure interaction applications - a review

Many structures used at sea must be able to withstand the occasional extreme weather conditions and the risk of underwater explosions. This applies not only for military ships and submarines but also for tankers and civil exploration and extraction platforms. An understanding is therefore required of the effects of shock induced water waves and unbounded fluid-structure interaction on floating and submerged structures. For modelling purposes these structures may be considered as a system of five components: the structure itself, any fluid within it, the surrounding fluid including the effects of cavitation, the farfield fluid medium and the effect of shock waves. The first two are sufficiently well understood, the remaining three are the subject of continuous research. Recent developments have created new possibilities for treating the farfield fluid medium. Hence, this paper which discusses the various methods used in the modelling of this problem.     

Pulmonary artery pressure: early predictor of chronic lung disease in preterm infants

AIM: To determine if pulmonary artery pressure (PAP) in ventilated preterm infants is independently associated with the development of chronic lung disease (CLD) and whether early assessment has any prognostic value. METHODS: Two cohorts (development n = 55; and validation n = 28) of preterm infants were studied at 24 hours of age. PAP was assessed non-invasively using its inverse correlation with the corrected acceleration time to right ventricular ejection time ratio (AT:RVET(c)), calculated from the pulmonary artery Doppler waveform. Clinical and respiratory variables were also collected. Using logistic regression analysis to identify factors independently associated with CLD, a prognostic score was developed to predict CLD. The ability of the score to predict CLD was described using receiver operating characteristic (ROC) curves. RESULTS: Birthweight, inspired oxygen concentration, and AT:RVET(c) were independently predictive of CLD. The area under the ROC curve was 0.96 for the development and 0.89 for the validation cohort. Exclusion of AT:RVET(c) resulted in a reduction to 0.88 and 0.73, respectively. CONCLUSION: PAP is independently associated with CLD. An early assessment of PAP using AT:RVET(c) may permit the early prediction of CLD as part of a multifactorial scoring system.     

Nuclear magnetic resonance characterization of reaction products of interesterification of peracetylated α-d-glucopyranose and fatty acid methyl esters

Mono- and diesters of fatty acids of peracetylated α-d-glucopyranose were prepared by chemical interesterification. Substituent-induced chemical shift effects on the carbonyl carbons rather than the ring carbons and proton atoms unambiguosly show the fatty acyl substituents to be at C1 in the monosubstituted, and at C1 and C6 in the disubstituted products. ¹H nuclear magnetic resonance (NMR) integration data before and after interesterification complemented ¹³C chemical shift data in verifying the molecular structures. Empirical data from classical ¹H and ¹³C NMR experiments thus provide a simple self-contained method for determining the number and position of fatty acyl substituents, and the anomeric compositions of peracetylated glucose fatty esters.     

Wind speed and wind energy potential of Jordan

Routine wind data from 11 stations in Jordan have been analysed. Monthly average, and seasonal wind speed and average power density distributions were determined for each station. The monthly average wind speed for the two most potential sites Ras Muneef (RA) and Mafraq (MF) ranged from 3.0 to 7.4 m/sec and the average power density for these two sites ranged from 110 to 370 W/m² at RA and from 105 to 470 W/m² at MF. An application of wind power as supplementary power supply is suggested and cost analysis is given.     

Physico‐mechanical and decay resistance properties of chemically modified tropical wood material

In this present research, several kinds of selected tropical light hardwoods were chemically modified with benzene diazonium salt to improve their physico‐mechanical and decay resistance properties. Benzene diazonium salt underwent a coupling reaction with wood which was confirmed through fourier transform infrared spectroscopic analysis. The compressive modulus of the treated wood increased, whereas modulus of rupture was shown to decrease on treatment. Water absorption was also found to decrease considerably after modification. The modified wood samples had higher hardness (Shore D) value compared to that of the control ones. The wood was exposed to two types of fungi; white‐rot (Polyporus versicolor) and brown‐rot (Postia placenta), for 12 weeks and then decay was assessed through weight loss percentage (%). A significant improvement was found in the modified wood compared to the control wood. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013