232 research outputs found
CP violation in decay
CP violation leads to a difference between the parameters and
describing the energy distributions of the charged pions produced in the and decays. We study the
difference as a function of the relative contributions from the
QCD-penguin and the electroweak-penguin diagrams. We find that the combination
of these contributions in is very similar to the corresponding
one defining the parameter in the decays. This
observation allows a determination of the value of , using data on
An experimental study of concrete resistivity and the effects of electrode configuration and current frequency on measurement
Electrical resistivity, a measurable parameter of the state of concrete, plays an important role in the assessment of reinforced concrete structures. An experimental study using two-electrode method has been conducted to evaluate the resistivity of Portland cement concrete. Internal and external electrodes were varied in order to understand effect of the electrodes configuration, where carbon fibre (CF) sheets were employed as the internal electrodes and CF and copper sheets were used as external electrodes. Furthermore, frequency of applied current was varied from low to high, to identify the most suitable frequency that can be utilized for stable and reliable results. Optimised internal electrodes configuration and the current frequency of 10,000 Hz were used to measure the resistivity on a series of concrete cubes, which were made using three different water to cement ratios and four different chloride contents
Modelling the electrical resistivity of concrete with varied water and chloride contents
The electrical resistivity of concrete is an important property in the assessment of reinforcement corrosion in concrete and an essential parameter in the design and operation of cathodic protection for reinforced-concrete (RC) structures. Water and chloride contents in concrete are highly variable in RC structures in real-world hostile environments, meaning that characterisation of their coupled effects on concrete electrical resistivity is important. The currently available models are investigated in this paper. As all the current models are purely empirical, an improvement with a semi-empirical model is proposed. The improvement highlights the intrinsic linkage between concrete electrical resistivity and water content and the pore size distribution of concrete. The proposed model was tested using two sets of experimental data and was also compared with other two empirical models
Hydrothermal synthesis of zeolites from coal fly ash
The fly ash, from the combustion of coal to produce energy and heat, is an industrial waste, in which large accumulations represent a serious environmental threat. To reduce the environmental burden and improve the economic benefits of energy production, the science and industry focus on the transformation of coal combustion byproducts into new functional materials. The fly ash was studied by modern analytical methods. As a result of the hydrothermal reaction, several types of zeolites were synthesised from the fly ash: analcime, faujasite (zeolite X) and gismondine (zeolite P). It was shown that the experimental conditions (temperature, reaction time and alkali concentration) have a significant influence on the type of zeolite and its content in the reaction products. The series of experiments resulted in building approximate crystallisation field of zeolites and other phases as the first stage of the formation of ceramic membrane and other materials
Characterization of Spatial Coherence of Synchrotron Radiation with Non-Redundant Arrays of Apertures
We present a method to characterize the spatial coherence of soft X-ray
radiation from a single diffraction pattern. The technique is based on
scattering from non-redundant arrays (NRA) of slits and records the degree of
spatial coherence at several relative separations from one to 15 microns,
simultaneously. Using NRAs we measured the transverse coherence of the X-ray
beam at the XUV X-ray beamline P04 of the PETRA III synchrotron storage ring as
a function of different beam parameters. To verify the results obtained with
the NRAs additional Young's double pinhole experiments were conducted and show
good agreement.Comment: 15 pages, 6 figures, 2 tables, 42 reference
On the Role of FSI in K -> 2\pi Decay
Contrary to wide-spread opinion that the final state interaction (FSI)
enlarges the amplitude , we argue that FSI is not able to
increase the absolute value of this amplitude.Comment: 10 pages, minor correction
Constraining CP Violating Phases of the MSSM
Possible CP violation in supersymmetric (SUSY) extensions of the Standard
Model (SM) is discussed. The consequences of CP violating phases in the gaugino
masses, trilinear soft supersymmetry-breaking terms and the `mu' parameter are
explored. Utilizing the constraints on these parameters from electron and
neutron electric dipole moments, possible CP violating effects in B-physics are
shown. A set of measurements from the B-system which would overconstrain the
above CP violating phases is illustrated.Comment: 14 pages, 6 figure
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