The article reports results from the largest international dose survey in paediatric computed tomography (CT) in 32 countries and proposes international diagnostic reference levels (DRLs) in terms of ...computed tomography dose index (CTDI vol) and dose length product (DLP). It also assesses whether mean or median values of individual facilities should be used. A total of 6115 individual patient data were recorded among four age groups: <1 y, >1-5 y, >5-10 y and >10-15 y. CTDIw, CTDI vol and DLP from the CT console were recorded in dedicated forms together with patient data and technical parameters. Statistical analysis was performed, and international DRLs were established at rounded 75th percentile values of distribution of median values from all CT facilities. The study presents evidence in favour of using median rather than mean of patient dose indices as the representative of typical local dose in a facility, and for establishing DRLs as third quartile of median values. International DRLs were established for paediatric CT examinations for routine head, chest and abdomen in the four age groups. DRLs for CTDI vol are similar to the reference values from other published reports, with some differences for chest and abdomen CT. Higher variations were observed between DLP values, based on a survey of whole multi-phase exams. It may be noted that other studies in literature were based on single phase only. DRLs reported in this article can be used in countries without sufficient medical physics support to identify non-optimised practice. Recommendations to improve the accuracy and importance of future surveys are provided.
Nanosized titanium dioxide (TiO
2) photocatalytic papers were successfully prepared using a natural zeolite microparticle retention aid in papermaking. Applying a factorial experimental design, ...natural zeolite has been demonstrated to be the most significant and interactive factor for increasing the TiO
2 retention rate in paper stock. The photocatalysis of as-prepared sheets was evaluated with toluene as one of the representative volatile organic compounds (VOCs). Under UV irradiation, it was shown to be effective in removing gaseous toluene by photodecomposition, assisted by adsorption. It was revealed that natural zeolite plays an important role in both increasing retention rate of TiO
2 nanoparticles and enhancing photocatalytic efficiency of the paper. The photocatalytic paper can be potentially applied for environmental purification.
The current deinking evaluation methods include visual image analysis (manual and digital) and optical reflectance (using the Kubelka-Munk equation). The mechanism of image analysis is simple: dark ...ink (mostly black) is isolated from the light background (fiber) and then captured visually or by digital devices. The image analysis methods have inherent limits, such as poor correlation with paper optical properties, and have large variances from sample to sample and side to side. In this paper, an innovative approach that employs a band of near infrared light and a digital imaging device was applied to address these limitations. This approach has advantages for isolating specks from backgrounds, obtaining high quality raw data, and significantly reducing the variances among the handsheets and their sides. By using the ink elimination equation derived from image analysis, reliable ink elimination rates were obtained that were well correlated with paper optical properties. This system was also applied to newspaper deinking evaluation with positive results.
Prerecycling of water-based flexographic ink and water-based thermal inkjet inks was explored. Model laboratory formulated water-based flexographic and commercial water-based thermal inkjet inks were ...used in experiments using solely wet or dry inks. The goal was to optimize ink detachment during repulping and at the same time assure its minimal ink redeposition. Ink’s behavior was examined under a wide pH range. An alkaline environment is desirable for complete ink detachment from the printed substrate, whereas the benefit of an acid environment is the agglomeration of the pigment in water-based ink. Deinking would be most efficient if executed in two steps: first, alkaline to detach most of the alkaline water-based ink and second, acidic to maintain detached ink coagulated. Acidic pH has the ability to agglomerate the pigment, once it is detached and present in deinking waters. However, such a recycling protocol is likely not achievable in current recycling plants.
Phase-change inks PEKAROVICOVA, Alexandra; BHIDE, Hrishikesh; FLEMING, Paul D ...
JCT, Journal of Coatings Technology,
2003, 2003-1-00, 20030101, Letnik:
75, Številka:
936
Journal Article, Trade Publication Article
Polyamide resins are obtained by condensation polymerization of an amine and an organic acid. They provide good ink adhesion, control the viscosity of the ink composition, inhibit the crystallization ...of waxes, impart transparency to the ink composition, and promote steric hindrance of pigments. The polyamide resins for hot melt ink formulation usually have an average molecular weight from 600 to 400,000 and are present in the ink composition in an amount between 5 and 60%.
