Efficient Management of Fines in the Stock Flow prior to Headbox in Paper, Board, and Tissue Production

Fines represent a significant volume of biobased wood material and filler, which is of significant importance to sheet quality. New imaging technology reveals the true nature of the behavior of fines in the retention process. This study illustrates new chemical mixing systems, novel and efficient flash mixing methods, and active measurement and automation systems pertaining to efficient management of fines in the stock flow prior to headbox in paper, board, and tissue production, which can reduce additive, fresh water, energy consumption, and the carbon footprint of production to improve sustainability and provide novel opportunities for fines and filler management.     

Polymeric dual-slab waveguide interferometer for biochemical sensing applications

A polymer based dual-slab waveguide Young's interferometer was demonstrated for biochemical sensing. Evanescent field is utilized for probing the binding events of biomolecules on the waveguide surface. Refractive index sensing in analyte and protein adsorption on the sensing surface were investigated with glucose de-ionized water solution and bovine serum albumin, immunoglobulin G solutions in phosphate buffered saline buffer. A detection limit of 10(-5) RIU and 4 pg/mm(2) was achieved for homogeneous and surface sensing, respectively. Also, the influence of water absorption inside the polymeric device on the measurement stability was evaluated. The results indicate that the waveguide polymer sensor fabricated with the spin coating technique can achieve a satisfactory sensitivity for homogeneous refractive index sensing and, as well, for monitoring molecular binding events on the surface.     

Interaction of Helium Rydberg State Atoms with Superfluid Helium

The pair potentials between ground state helium and Rydberg He $^*(2s,2p,3s)$ atoms are calculated by the full configuration interaction electronic structure method for both the electronic singlet and the triplet manifolds. The obtained pair potentials are validated against existing experimental molecular and atomic data. Most states show remarkable energy barriers at long distances ( $R > 5$ Å), which can effectively stabilize He $^*$ against the formation of He $_2^*$ at low nuclear kinetic energies. Bosonic density functional theory calculations, based on the calculated pair potential data, indicate that the triplet ground state He $^*$ reside in spherical bubbles in superfluid helium with a barycenter radius of 6.1 Å at the liquid saturated vapor pressure. The pressure dependency of the relative He $^*$ $2s$ $^3S$ $\rightarrow $ $2p$ $^3P$ absorption line blue shift in the liquid was obtained through both the statistical line broadening theory as well as the dynamic adiabatic following method. The pronounced difference between the results from the static and dynamic models is attributed to the dynamic Jahn–Teller effect that takes places in the electronically excited state within the dephasing time of 150 fs. Transient non-thermalized liquid surroundings near He $^*$ may contribute to an artificial reduction in the absorption line blue shift by up to 30 cm $^{-1}$ .     

Thermochromism of fluorescent colors

Fluorescence (sometimes called rapid luminescence or just luminescence) has been scientifically studied for 150 years. Recent advances in daylight simulators, ultraviolet filters, and measurement devices (for example, advances in the commercial two‐monochromator measurement devices) have made it possible to study this phenomenon more accurately. Many factors affect the color of a fluorescent object. One of these factors is the temperature of the sample. It is known that, for example, the reflectance of the nonfluorescent ceramic color reference tiles used for calibration of colorimeters and spectrophotometers is temperature dependent. This phenomenon is called thermochromism, which means a reversible change of a color of the sample as a function of temperature. The phenomenon can also be detected in fluorescent colors, although fluorescent samples show quite different thermochromic properties that have not been extensively studied and are partly unknown. In this article we first discuss the thermochromism of nonfluorescent samples. We consider the meaning of thermochromism for fluorescent color measurements. Novel experimental data are provided and the temperature‐dependent changes in samples' radiance spectra are analyzed and proven to be significant. In some fluorescent samples the thermochromic changes can be as high as 4 times the thermochromic changes in some nonfluorescent samples in the same temperature scale (e.g., red fluorescent paint sample versus red ceramic sample, with equivalent temperature changes). In addition, a two‐component thermochromic model is introduced to discuss the phenomenon of thermochromism more closely. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 163–171, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20104     

Highlight detection and removal from spectral image

We present a constrained spectral unmixing method to remove highlight from a single spectral image. In the constrained spectral unmixing method, the constraints have been imposed so that all the fractions of diffuse and highlight reflection sum up to 1 and are positive. As a result, the spectra of the diffuse image are always positive. The spectral power distribution (SPD) of the light source has been used as the pure highlight spectrum. The pure diffuse spectrum of the measured spectrum has been chosen from the set of diffuse spectra. The pure diffuse spectrum has a minimum angle among the angles calculated between spectra from a set of diffuse spectra and the measured spectrum projected onto the subspace orthogonal to the SPD of the light source. The set of diffuse spectra has been collected by an automated target generation program from the diffuse part in the image. Constrained energy minimization in a finite impulse response linear filter has been used to detect the highlight and diffuse parts in the image. Results by constrained spectral unmixing have been compared with results by the orthogonal subspace projection (OSP) method [Proceedings of International Conference on Pattern Recognition (2006), pp. 812-815] and probabilistic principal component analysis (PPCA) [Proceedings of the 4th WSEAS International Conference on Signal Processing, Robotics and Automation (2005), paper 15]. Constrained spectral unmixing outperforms OSP and PPCA in the visual assessment of the diffuse results. The highlight removal method by constrained spectral unmixing is suitable for spectral images.