440 research outputs found

    Printed Dot Quality in Response to Doctor Blade Angle in Gravure Printing

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    Doctor blade is one of the critical machine part of the gravure printing press that controls the amount of ink transfer on the substrate. The angle of the blade can be varied; however, an improper angle may cause major problems. In this study, the doctor blade angle was positioned at three different level to address its effect on the printed dot quality. Print trials were made on a web-fed gravure press at the speed of 650 ft./min. A high-resolution overhead camera was used to analyze the key dot attributes. The results showed that measuring only the density of printed dot –a traditional quality control method– is insufficient. Incorporating the camera was assisted capturing missing dots, as well as quantifying dot area, perimeter and circularity. Print trials showed that the image quality was undesirable, when the blade angle exceeded or fell behind the optimum position

    The effect of green biobased binder on structural, mechanical, liquid absorption and wetting properties of coated papers

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    Synthetic styrene-butadiene (SB) and styrene-acrylic (SA) latex binders used in paper coating formulations are common and based on unsustainable petroleum sources. Today\u27s papermaking industry turns towards sustainable substitutes that do not compromise quality, and reduce carbon emission, toxic substance release and waste disposal concerns related to fossil fuel sources. In this study, colloidal starch-based latex nanoparticles that do not require cooking were used for pigment coating and coated on the paper surfaces. The effects of these new biobased binders on the structural and mechanical strength properties, liquid absorption, wetting and surface topography of the paper were investigated and compared with the properties of coated paper that SB latex was used as a coating binder. The results demonstrated that the biobased latex decreases the grammage of paper while maintaining an identical thickness relative to the SB latex samples. The porosity, permeability and roughness of biobased latex are found higher than the SB latex. The biobased latex successfully replaced SB latex at 1:1 ratio and enabled an equivalent of bursting, tear, tensile strength and structural properties

    Controlling unequal surface energy results caused by test liquids: the case of UV/O3 Treated PET

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    Ultraviolet/ozone (UV/O3) treatment has been reported to be an effective method to modify properties such as wettability, adhesion or adsorption of plastic surfaces. The change in the surface is measured by contact angle analysis, which employs liquids and their surface tensions (ST) to estimate the surface energy (SE). We found two different practices in the scientific community: (1) the majority of researchers adopted the ST value of liquids from the literature, while (2) other researchers conducted real-time measurements in the lab under ambient conditions prior to SE estimation. To the best of our knowledge, there is no study that compares the difference between the two practices. One study was found to show different SE methods generating unequal SE values for the same substrate. However, there was no definitive conclusion backed by general thermodynamics rules. In this study, we presented (1) a statistical significance test that showed the literature and experimental ST values are significantly different, and studied (2) the effect of different liquid pairs on the SE estimation for UV/O3 treated poly(ethylene terephthalate) (PET) substrate. Modification techniques such as atmospheric pressure plasma or chemical modification were studied previously to examine PET’s wettability and the SE. The UV/O3 treatment was studied to improve adhesion and to modify its chemical properties for adsorption. In contrast, we studied (3) the effect of UV/O3 on wettability at different timeframes and addressed (4) how to control unequal SE based on a method that was refined on a rigorous thermodynamic three-phase system. It must be noted that this method can be generalized to other types of solid surfaces to estimate thermodynamically self-consistent SE values. This work also provides (5) a web-based calculator that complements computational findings available to the readership in the data availability section

    Corticosteroid injection for tennis elbow or lateral epicondylitis: a review of the literature

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    Lateral epicondylitis or tennis elbow is a painful and functionally limiting entity affecting the upperextremity and is frequently treated by hand surgeons. Corticosteroid injection is one of the most common interventions for lateral epicondylitis or tennis elbow. Here, a review of the medical literature on this treatment is presented

    On the connection between the intergalactic medium and galaxies: the H I–galaxy cross-correlation at z ≲ 1

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    We present a new optical spectroscopic survey of 1777 ‘star-forming’ (‘SF’) and 366 ‘non-star-forming’ (‘non-SF’) galaxies at redshifts z ∼ 0-1 (2143 in total), 22 AGN and 423 stars, observed by instruments such as the Deep Imaging Multi-Object Spectrograph, the Visible Multi-Object Spectrograph and the Gemini Multi-Object Spectrograph, in three fields containing five quasi-stellar objects (QSOs) with Hubble Space Telescope (HST) ultraviolet spectroscopy. We also present a new spectroscopic survey of 173 ‘strong’ (1014 ≤ NHI≲ 1017 cm−2) and 496 ‘weak’ (1013 ≲ NHI 50 per cent of ‘weak’ H i systems reside within galaxy voids (hence not correlated with galaxies), and are confined in dark matter haloes of masses smaller than those hosting ‘strong’ systems and/or galaxies. We speculate that H i systems within galaxy voids might still be evolving in the linear regime even at scales ≲2 Mpc

    Acerca de uma leitura geopolítica das relações entre Portugal e o Atlântico

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    O artigo pretende traçar uma breve perspectiva geopolítica da relação entre Portugal e o oceano Atlântico. Essa relação, embora sempre presente e importante, variou ao longo da nossa histó- ria. O autor, depois de tentar sumariamente caracterizar essas variações, analisa simplificadamente aquela relação no actual contexto do sistema global das relações internacionais. Dessa análise retira argumentos para afirmar que na ligação com o Atlântico poderão de novo ser encontradas as soluções mais adequadas para os nossos actuais problemas do desenvolvimento e da afirmação internacional, através da possível e desejável futura assumpção por Portugal de um papel de entreposto de importantes fluxos nas relações transatlânticas, em que as luso-brasileiras e as com a CPLP deverão desempenhar um papel centra
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