A two-stage ceramic tile grout sealing process using a high power diode laser Part I: Grout development and materials characteristics

Work has been conducted using a 60 W-cw high power diode laser (HPDL) in order to determine the feasibility and characteristics of sealing the void between adjoining ceramic tiles with a specially developed grout material having an impermeable enamel surface glaze. A two-stage process has been developed using a new grout material which consists of two distinct components: an amalgamated compound substrate and a glazed enamel surface; the amalgamated compound seal providing a tough, heat resistant bulk substrate, whilst the enamel provides an impervious surface. HPDL processing has resulted in crack free seals produced in normal atmospheric conditions. The basic process phenomena are investigated and the laser effects in terms of seal morphology, composition and microstructure are presented. Also, the resultant heat affects are analysed and described, as well as the effects of the shield gases, O2 and Ar, during laser processing. Tiles were successfully sealed with power densities as low as 500 W/cm2 and at rates up to 600 mm/min. Contact angle measurements revealed that due to the wettability characteristics of the amalgamated oxide compound grout (AOCG), laser surface treatment was necessary in order to alter the surface from a polycrystalline to a semi-amorphous structure, thus allowing the enamel to adhere. Bonding of the enamel to the AOCG and the ceramic tiles was identified as being principally due to van der Waals forces, and on a very small scale, some of the base AOCG material dissolving into the glaze

Entanglement of bosonic modes of nonplanar molecules

Entanglement of bosonic modes of material oscillators is studied in the context of two bilinearly coupled, nonlinear oscillators. These oscillators are realizable in the vibrational-cum-bending motions of C-H bonds in dihalomethanes. The bilinear coupling gives rise to invariant subspaces in the Hilbert space of the two oscillators. The number of separable states in any invariant subspace is one more than the dimension of the space. The dynamics of the oscillators when the initial state belongs to an invariant subspace is studied. In particular, the dynamics of the system when the initial state is such that the total energy is concentrated in one of the modes is studied and compared with the evolution of the system when the initial state is such wherein the modes share the total energy. The dynamics of quantities such as entropy, mean of number of quanta in the two modes and variances in the quadratures of the two modes are studied. Possibility of generating maximally entangled states is indicated.Comment: 21 pages, 6 figure

Determination of the absorption length of CO2, Nd:YAG and high power diode laser radiation for a selected grouting material

The laser beam absorption lengths of CO2, Nd:YAG and a high power diode laser (HPDL) radiation for a newly developed SiO2/Al2O3-based tile grout have been determined through the application of Beer-Lambert’s law. The findings revealed marked differences in the absorption lengths despite the material having similar beam absorption coefficients for the lasers. The absorption lengths for the SiO2/Al2O3-based tile grout for CO2, Nd:YAG and HPDL radiation were calculated as being 23211 m, 1934 m and 1838 m respectively. Moreover, this method of laser beam absorption length determination, which has hitherto been used predominantly with lasers operated in the pulsed mode, is shown to be valid for use with lasers operated in the continuous wave (CW) mode, depending upon the material being treated

An improved experimental test set-up to study the performance of granular columns

This paper describes an innovative design of a newly developed large test setup for testing the performance of footings supported on soft clay reinforced with granular columns. This advanced testing method is used to examine the settlement of footings supported on granular columns. Two important features of the equipment are (a) the axial loading system which allows samples to be consolidated under Ko condition while the load is applied onto a small foundation area of the sample, and (b) a relatively large sample size of 300-mm diameter and 400-mm high. The system is also equipped with pressure cells located beneath the footing and top cap to measure the pressure distribution with respect to foundation displacement and a lateral strain gage to monitor boundary effects. This paper reports on some of the early findings from the preliminary tests carried out using this equipment. Samples for testing were prepared by consolidating kaolin slurry in a large one-dimensional consolidation chamber. The granular columns were installed using the replacement method by compacting crushed basalt (uniformly graded with 90 % between 1.5–2-mm particle sizes) into a preformed hole. The preliminary tests have yielded promising results, validating the functionality of the equipment and support the prospect of increasing the knowledge with respect to settlement response and design of a footing supported on granular columns

Multilayered feed forward Artificial Neural Network model to predict the average summer-monsoon rainfall in India

In the present research, possibility of predicting average summer-monsoon rainfall over India has been analyzed through Artificial Neural Network models. In formulating the Artificial Neural Network based predictive model, three layered networks have been constructed with sigmoid non-linearity. The models under study are different in the number of hidden neurons. After a thorough training and test procedure, neural net with three nodes in the hidden layer is found to be the best predictive model.Comment: 19 pages, 1 table, 3 figure

Photon-added coherent states as nonlinear coherent states

The states $|\alpha,m>$, defined as ${a^{\dagger}}^{m}|\alpha>$ up to a normalization constant and $m$ is a nonnegative integer, are shown to be the eigenstates of $f(\hat{n},m)\hat{a}$ where $f(\hat{n},m)$ is a nonlinear function of the number operator $\hat{n}$. The explicit form of $f(\hat{n},m)$ is constructed. The eigenstates of this operator for negative values of $m$ are introduced. The properties of these states are discussed and compared with those of the state $|\alpha,m >$.Comment: Rev Tex file with two figures as postscript files attached. Email: [email protected]

Interpolating Coherent States for Heisenberg-Weyl and Single-Photon SU(1,1) Algebras

New quantal states which interpolate between the coherent states of the Heisenberg_Weyl and SU(1,1) algebras are introduced. The interpolating states are obtained as the coherent states of a closed and symmetric algebra which interpolates between the two algebras. The overcompleteness of the interpolating coherent states is established. Differential operator representations in suitable spaces of entire functions are given for the generators of the algebra. A nonsymmetric set of operators to realize the Heisenberg-Weyl algebra is provided and the relevant coherent states are studied.Comment: 13 pages nd 5 ps figure

Predicting blunt cerebrovascular injury in pediatric trauma: Validation of the Utah Score

Risk factors for blunt cerebrovascular injury (BCVI) may differ between children and adults, suggesting that children at low risk for BCVI after trauma receive unnecessary computed tomography angiography (CTA) and high-dose radiation. We previously developed a score for predicting pediatric BCVI based on retrospective cohort analysis. Our objective is to externally validate this prediction score with a retrospective multi-institutional cohort. We included patients who underwent CTA for traumatic cranial injury at four pediatric Level I trauma centers. Each patient in the validation cohort was scored using the “Utah Score” and classified as high or low risk. Before analysis, we defined a misclassification rate <25% as validating the Utah Score. Six hundred forty-five patients (mean age 8.6 ± 5.4 years; 63.4% males) underwent screening for BCVI via CTA. The validation cohort was 411 patients from three sites compared with the training cohort of 234 patients. Twenty-two BCVIs (5.4%) were identified in the validation cohort. The Utah Score was significantly associated with BCVIs in the validation cohort (odds ratio 8.1 [3.3, 19.8], p < 0.001) and discriminated well in the validation cohort (area under the curve 72%). When the Utah Score was applied to the validation cohort, the sensitivity was 59%, specificity was 85%, positive predictive value was 18%, and negative predictive value was 97%. The Utah Score misclassified 16.6% of patients in the validation cohort. The Utah Score for predicting BCVI in pediatric trauma patients was validated with a low misclassification rate using a large, independent, multicenter cohort. Its implementation in the clinical setting may reduce the use of CTA in low-risk patients

Chiral Solitons in a Current Coupled Schr\"odinger Equation With Self Interaction

Recently non-topological chiral soliton solutions were obtained in a derivatively coupled non-linear Schr\"odinger model in 1+1 dimensions. We extend the analysis to include a more general self-coupling potential (which includes the previous cases) and find chiral soliton solutions. Interestingly even the magnitude of the velocity is found to be fixed. Energy and U(1) charge associated with this non-topological chiral solitons are also obtained.Comment: 8 pages, no figure, to appear in Phys. Rev.

Constraints on the quantum gravity scale from kappa - Minkowski spacetime

We compare two versions of deformed dispersion relations (energy vs momenta and momenta vs energy) and the corresponding time delay up to the second order accuracy in the quantum gravity scale (deformation parameter). A general framework describing modified dispersion relations and time delay with respect to different noncommutative kappa -Minkowski spacetime realizations is firstly proposed here and it covers all the cases introduced in the literature. It is shown that some of the realizations provide certain bounds on quadratic corrections, i.e. on quantum gravity scale, but it is not excluded in our framework that quantum gravity scale is the Planck scale. We also show how the coefficients in the dispersion relations can be obtained through a multiparameter fit of the gamma ray burst (GRB) data.Comment: 9 pages, final published version, revised abstract, introduction and conclusion, to make it clear to general reade