An ecological approach to printing industry: Development of ecofriendly offset printing inks using vegetable oils and pine resin as renewable raw materials and evaluation of printability

Petroleum-based solvents and synthetic resins are used as raw materials for the production of varnish, which is one of the main components of offset printing inks. These petrochemical compounds that are released to the surrounding in printing process demonstrates harmful effects on environment and human health. In the light of these facts, this study was carried out to investigate the use of renewable natural resources for offset printing inks production to lower environmental impacts and protect human health. In this study, different vegetable-based offset printing inks were developed with safflower oil (SO); grape seed oil (GSO) and Pinus pinaster resin (PPR) and printability analysis were performed. To understand the effect of pine resin in the ink formulation an ink sample with mineral oil (MO) was also produced. Printing tests were carried out with coated papers and the IGT C1 offset printability tester. Color, gloss, rub resistance, viscosity and tack values were measured on the test prints. Comparison of results with standard values figured out the suitability of using the newly developed offset printing inks for printing industry. The color difference values of color differences were in range of tolerance value. The density value of SO-PPR ink was found as same with standard values while the density value GSO-PPR and MO-PPR inks were measured close to standards as 1.45, 1.42, and 1.46, respectively. The results of printability analysis demonstrated appropriate utilization of the renewable sources for ecological development of offset printing inks.     

Influence of passive ultrasonic irrigation on the efficiency of various irrigation solutions in removing smear layer: a scanning electron microscope study

To evaluate the influence of passive ultrasonic irrigation (PUI) to remove the smear layer with different irrigation solutions. Seventy‐eight single rooted mandibular premolars were used. The working lengths were measured and the root canals were prepared by using nickel titanium rotary files. The specimens were subjected to six different irrigation regimens: sodium hypochloride (NaOCl) with classic irrigation (CI); NaOCl with PUI; EDTA with CI; EDTA with PUI; QMix with CI; and QMix with PUI. The specimens were split longitudinally. Scanning electron microscopy images were taken to evaluate the amount of residual smear layer and scored. Statistical analysis was performed with the Kruskal–Wallis test. The Dunn's test was used for post hoc testing after the Kruskal–Wallis test. The smear layer scores of apical thirds were significantly higher than coronal and middle thirds except for NaOCl + CI group (p < 0.001). The irrigation with PUI improved the efficacy of all irrigation solutions on removal of smear layer in both coronal and middle thirds (p < 0.001). The PUI activation increased the activity of NaOCl, EDTA, and QMix, respectively without any significance. All irrigation regimens were significantly more effective in coronal and middle thirds compared to apical third. PUI significantly increased the efficacy of smear layer removal regardless of irrigation solution.     

GM and KM immunoglobulin allotypes in a Spanish Pyrenean population: Val d'Aran

Four hundred and thirteen unrelated individuals (202 autochthonous and 211 non-autochthonous) of Val d'Aran (Catalan Pyrenees) have been analysed for the GM and KM immunoglobulin genetic system using the inhibition haemagglutination method. This population was defined by eight GM haplotypes (GM*3 23 5*, GM*3 5*, GM*1,17 21,28, GM*1,2,17 21,28, GM*1,17 5*, GM*1,17 5,6,11,24, GM*1,17 10,11,13,15 and GM*1,17 10,11,13,15,16) inferred from the 17 observed phenotypes. The Val d'Aran population frequencies conform to Hardy-Weinberg expectations. The frequencies of phenotypes and haplotypes show a definite homogeneity between the autochthonous and non-autochthonous people of Val d'Aran and 11 other Pyrenean populations (Mauléon, Macaye, St. Jean Pied de Port, Vallée de L'Ouzom, Gavarnie, Barèges, Luz St. Sauveur, Esparros, Camurac, Capcir and Pays de Sault) that have already been studied for the same allotypes. A factorial correspondence analysis was performed for the 12 autochthonous Pyrenean populations, showing a high frequency of the GM*3 23 5* haplotype in the three Pyrenean regions (Western, Central and Eastern), while the GM*1,17 21,28 haplotype is mainly found in the Central region, GM*3 5* in the Eastern and Western zones, and the GM*1,2,17 21,28 is mainly present in the Central and Eastern populations. The results show a relative regional homogeneity, so there is no evidence of a frequency gradient in the Pyrenean populations for the GM and KM genetic systems. It may, however, be noticed that the Central Pyrenean populations form a group, with one population (Vallée de l'Ouzom) isolated from the rest, probably because of its particular model of inheritance by which the heritage is passed to the first born without sex consideration. It has been possible to point out some differences in the genetic structure of the autochthonous and non-autochthonous Val d'Aran population and to place the autochthonous Aranese group among its Pyrenean neighbours.     

Evaluation of plant-based oils for production of offset printing ink

The oils and solvents are the main components of the printing ink, and the chemical composition of the ink could be harmful or toxic to human health and the environment. Therefore, there is an increasing demand to develop inks containing green, biobased, sustainable, and renewable raw materials instead of petrochemical substances. In this study, flaxseed oil (FO), pomegranate seed oil, plum kernel oil (PKO), and grape seed oil (GSO) were selected to produce offset printing inks. Pinus pinaster (P. pinaster) resin was also used in the formulation of inks to examine the effects of natural resin on ink together with vegetable oils. The phenolic content was analyzed for the resin and oils to figure out their potential antioxidant and bioactive characteristics. Optical and rheological tests were applied to evaluate the printability of the inks. L*a*b*, ΔE, density, and gloss tests were performed for optical evaluation. The viscosity, tack, and rub resistance tests were applied to perform rheological analysis. The biobased, environmental friendly, and self-drying (cold set) offset printing inks were obtained using natural pine resin and three different plant-based oils FO, PKO, and GSO. The printability analysis of the inks figured out the potential usage of plant-based oils in the offset printing ink formulation.     

Inhibition of pyrite corrosion and photocorrosion by MEKF-R modified carbazoles

In this study natural iron sulfide (FeS₂) surface was coated by films of poly(N-vinylcarbazole) (PNVCz), poly(N-vinylcarbazole methylethylketoneformaldehyde resin) (P[NVCz-MEKF-R]), carbazole methylethylketone formaldehyde resin (Cz-MEKFR) and poly(carbazole methyl ethylketone formaldehyde resin) (P[Cz-MEKFR]). The corrosion, photocorrosion, and photoactivity characteristics of coated electrodes were investigated in potassium iodide/iodide (KI/I₂) redox electrolyte. The inhibition effect and photoactivity of Cz-MEKF-R, P[Cz-MEKF-R] P[NVCz-MEKFR] and PNVCz homopolymer coatings were compared. Coating performance was tested by polarization and electrochemical impedance (EIS) measurements. The photopotential and photocurrent values of bare and coated pyrite electrodes were obtained under illuminated conditions. The inhibition efficiencies were calculated from corrosion currents obtained by Tafel extrapolation from polarization curves.     

Exact 3D Saint Venant type solutions for piezoelectric d 15 shear-mode bi-morph and sandwich torsion actuation and sensing problems

This paper is concerned with the analysis of two types of piezoelectric torsion transducers using the d ₁₅-effect of mono-morph piezoelectric materials. The first problem is concerned with a bi-morph transducer made of two identical mono-morph straight rods, which are perfectly bonded to each other along their width; the polarization direction is parallel, but opposite in sign, such that the piezoelectric material parameter d ₁₅ has an opposite sign as well. The second problem sandwiches the bi-morph transducer between two identical elastic face layers. In both cases, the resulting transducer represents a torsion transducer. Therefore, we analyze the electromechanically coupled problem in the framework of Saint Venant’s torsion theory for straight rods taking into account the electrical problem as well. The results of our approach are compared to electromechanically coupled three-dimensional finite element computation and a very good agreement for the mechanical as well as the electrical entities is achieved, in particular for the rate-of-twist, the axial warping function, and the sensed voltage.     

Photocurable pentaerythritol triacrylate/lithium phenyl-2,4,6-trimethylbenzoylphosphinate-based ink for extrusion-based 3D printing of magneto-responsive materials

Recent advances in additive manufacturing made it feasible to fabricate products with desired shapes and features. Herein, a new, photocurable 3D printer ink mainly based on pentaerythritol triacrylate (PETA) is reported. To achieve rapid curing needed for 3D printing process, high performance water-soluble photoinitiator, lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP), was emulsified in PETA monomers and this suspension was evaluated for its polymerization kinetics by exposing to 395 nm UV-light. The distinct influences of LAP and triethanolamine (TEA) concentrations on photo-polymerization and printability were examined and an optimum concentration for extrusion-based 3D printing was found to be 10 mM and 1.62 M for LAP and TEA, respectively. Synthesized PETA-based 3D printer ink was functionalized by dispersing magnetic particles/flakes into the mixture, and consequently, a magneto responsive ink was obtained to be used in specialized applications. A ring-shaped structure embedded with micron sized iron flakes was printed as a prototype. This study presents a versatile photo-curable polymer formulation with possible translation to high performance 3D printing of customizable shapes that can be utilized in a wide range of areas such as micro-robotics and medical science.