Real-Time Cure Monitoring of Unsaturated Polyester Resin from Ultra-Violet Curing

Real time Fourier transform infrared (RTFT-IR) spectroscopy reveals the influence of the nature of the photoinitiator on the kinetics for the polymerization reaction. Real time cure monitoring was used to determine the polymerization rate of ultra-violet cured unsaturated polyester resins (UPR1:2-1:5) based on palm oil and containing styrene as a cross-linking agent in the presence of IRGACURE 184 photoinitiator. Firstly, variable types of UPR1:2-1:5 were prepared using various ratios of monoglyceride (MG) monomer to maleic anhydride which used as a source of double bond using polycondensation technique. RTFT-IR spectroscopy was used to characterize the ultra-violet curing kinetics for all the systems. This technique offered a powerful approach for monitoring changes in the chemical properties of the system during the ultra-violet curing. Pseudo first order kinetics for all UPR1:2-1:5 curable systems were determined and the rate constant values and regression coefficients were calculated. Furthermore, the thermal behaviour and morphological features for the photo-fabricated UPR1:2-1:5 systems were examined. The thermal analyses for the cured films were evaluated by TGA, DTG and DSC in nitrogen atmosphere at a heating rate of 10°C/min. All the formulations showed similar degradation pattern at 40 % and 50 % weight losses (Td = 40% and Td =50% respectively) except polymer UPR1:5 which had somewhat lower degree in the same range. In addition, the morphological properties for photo-fabricated UPR1:2,1:3,1:5 were investigated by using scanning electron microscopy.

Trans-esophageal endobronchial ultrasound-guided needle aspiration (EUS-B-NA) : a road map for the chest physician

The endobronchial ultrasound (EBUS) scope has been increasingly used in the gastrointestinal tract (EUS-B). Scientific data proves its efficacy and safety to provide a complete lung cancer staging, when combined with EBUS-TBNA, and in the diagnosis of para-esophageal lesions. There are multiple barriers to start performing EUS-B but probably the most important ones are related to knowledge and training, so new operators should follow a structured training curriculum. This review aims to reflect the best current knowledge regarding EUS-B and provide a road map to assist those who are incorporating the technique into their clinical practice

Corrosion and fatigue of oil well drilling steels

Oil drilling requires that miles of steel drill pipe, called the drill string, be exposed to fatigue loading and corrosive environments. Furthermore, it has been reported that pitting corrosion is responsible for initiating catastrophic drillstring failure. Pitting corrosion is responsible for initiating fatigue cracks, with pits acting as local stress raisers. This project investigates the pitting corrosion susceptibility and influence on fatigue life of high strength low alloy drillstring steels S-135 and UD-165 in a simulated drilling completion fluid, 6.7 M CaCl₂. Immersion test results show that both alloys are susceptible to pitting corrosion and a non-protective film of hydrated rust (FeOOH) was found. Non-metallic inclusions are well known to initiate pits in carbon steels. Preliminary testing of S-135 shows inclusions rich in Mn and S, while UD-165 shows inclusions rich in either Fe, Al and O, or Nb and C. Potentiodynamic scans of both alloys show active dissolution. Cyclic voltrammetry results shows a repassivation potential in the cathodic region. Through potentiostatic testing pit growth was found to be independent of anodic polarization time, meaning pit growth was unachievable through anodic polarization. Shallow, wide pits (3-5μm deep, 10-50μm wide) were only observed after the potentiostatic anodic polarization. Fatigue testing was performed on three surface treatments: 1) virgin 2) pitted by galvanostatic methods, and 3) pitted by galvanostatic methods, dried and left in the laboratory (20°C, 20-40% humidity) for 14 days. Statistical testing by Student's t-tests showed that UD-165 had a statistically significant drop in fatigue life for 1) virgin samples against 2) pitted samples while no significant drop was found for S-135. Both UD-165 and S-135 showed no statistically significant drop in fatigue life for 1) virgin samples against 3) samples pitted and left in the laboratory for 14 days.Keywords: fatigue, corrosion, oil drilling, drill string, high strength low alloy stee

Effect of CAR activation on selected metabolic pathways in normal and hyperlipidemic mouse livers

<p>Abstract</p> <p>Background</p> <p>Detoxification in the liver involves activation of nuclear receptors, such as the constitutive androstane receptor (CAR), which regulate downstream genes of xenobiotic metabolism. Frequently, the metabolism of endobiotics is also modulated, resulting in potentially harmful effects. We therefore used 1,4-Bis [2-(3,5-dichloropyridyloxy)] benzene (TCPOBOP) to study the effect of CAR activation on mouse hepatic transcriptome and lipid metabolome under conditions of diet-induced hyperlipidemia.</p> <p>Results</p> <p>Using gene expression profiling with a dedicated microarray, we show that xenobiotic metabolism, PPARα and adipocytokine signaling, and steroid synthesis are the pathways most affected by TCPOBOP in normal and hyperlipidemic mice. TCPOBOP-induced CAR activation prevented the increased hepatic and serum cholesterol caused by feeding mice a diet containing 1% cholesterol. We show that this is due to increased bile acid metabolism and up-regulated removal of LDL, even though TCPOBOP increased cholesterol synthesis under conditions of hyperlipidemia. Up-regulation of cholesterol synthesis was not accompanied by an increase in mature SREBP2 protein. As determined by studies in CAR -/- mice, up-regulation of cholesterol synthesis is however CAR-dependent; and no obvious CAR binding sites were detected in promoters of cholesterogenic genes. TCPOBOP also affected serum glucose and triglyceride levels and other metabolic processes in the liver, irrespective of the diet.</p> <p>Conclusion</p> <p>Our data show that CAR activation modulates hepatic metabolism by lowering cholesterol and glucose levels, through effects on PPARα and adiponectin signaling pathways, and by compromising liver adaptations to hyperlipidemia.</p

THE FINANCIAL EFFICIENCY OF THE APPLE PRODUCTION IN BOSNIA AND HERZEGOVINA

Opća tendencija smanjenja poljoprivrednih zemljišnih površina i globalnog povećanja broja stanovnika postavlja pred proizvođača jabuka zadatak, kako na manjim površinama proizvesti veće količine jabuka i kod toga uzeti u obzir i sve važnije ekološke standarde. Taj zadatak se može riješiti primjenom suvremenih uzgojnih oblika na načelima integrirane voćarske proizvodnje jabuka. Ova načela polaze od pretpostavke zaštite čovjekove okoline i postizanje visokih prinosa i visokih ekonomsko-fi nancijskih rezultata. Za primjenu ovih načela potrebno je usvajanje novih tehnologija uzgoja jabuka i prihvatanje suvremenih upravljačkih sustava menadžmenta u voćarstvu. U radu je prikazana Cost/benefi t analiza integrirane proizvodnje jabuke. Rezultati pokazuju, da je integrirana proizvodnja jabuke u Bosni i Hercegovini ekonomski i fi nancijski opravdana, pod pretpostavkom postizanja očekivanih prinosa i cijena.General trend of decreasing agricultural land area and global population increase sets new challenges for apple producers. This basically calls for more effi cient apple production. The integrated apple production is based on principles that combine fi nancially viable intensive production and simultaneously consider environment standards could be a solution to emerging problems in apple production. For implementation of this systems new technology standards and orchard management must be applied. The aim of this paper is the cost benefi t analysis of integrated apple production in BIH. The result show that integrated apple production in BIH is economically viable, assuming that expected yield and prices would be achieved

Influence of electrical stimulation on regeneration of the radial nerve in dogs

The effects of biphasic electric fields on nerve regeneration that follows injury to the left radial nerve were studied in dogs by electromyography (EMG). Left and right radial nerves were crushed with a serrated haemostat. Stimulating electrodes were positioned proximally and distally to the site of the injury. The left nerves received rectangular, biphasic and current pulses (30 µA, 0.5 Hz) through the injury for two months. The right radial nerves were treated as controls and regenerated without electrical stimulation. EMG activities were recorded intramuscularly from the left and right musculus extensor digitalis communis (MEDC). Results obtained at the end of the two-month stimulation period showed a significant difference in EMG activity between the left (stimulated) and the right (non-stimulated) MEDC, suggesting that electrical treatment enhanced nerve regeneration

Charge Transfer via Temporary Bonds in C60+C60+C_{60} + C_{60}^+ Molecular Collisions

We present a theoretical description of resonant charge transfer in collisions of nano-particles, specifically for $C_{60} + C_{60}^+$ collisions. We predict that transient bonds between colliding fullerenes can significantly extend the interaction time, allowing for a greater probability of charge transfer. In our model, the dumbbell-shaped $(C_{60}-C_{60})^+$ quasi-molecule, that is temporarily formed during the collision, is described as a dynamic system of 120 zero-range potentials. Using this model, we calculate the exchange interaction between colliding fullerenes and subsequently determine the corresponding charge transfer cross sections at different collision velocities. Our results have been verified with data obtained from quantum molecular dynamics simulations of the fullerene collisions. The presented theoretical model provides a description of the experimental data on the $C_{60} + C_{60}^+$ resonant charge transfer collision through the inclusion of the temporary formation of dumbbell-shaped fullerene molecules at low collision velocities.Comment: 5 pages (6 if you include citations), 3 figure

Impact of the absolute rutile fraction on TiO2 visible-light absorption and visible-light-promoted photocatalytic activity

Titanium dioxide is by far the most used semiconductor material for photocatalytic applications. Still, it is transparent to visible-light. Recently, it has been proved that a type-II band alignment for the rutile − anatase mixture would improve visible-light absorption. In this research paper we thoroughly characterised the real crystalline and amorphous phases of synthesised titanias – thermally treated at different temperatures to get distinct ratios of anatase-rutile-amorphous fraction – as well as that of three commercially available photocatalytic nano-TiO2. Optical spectroscopy showed that even a small fraction of rutile (2 wt%) is able to shift to lower energies the apparent optical band gap of an anatase-rutile mixed phase. But is this enough to attain a real photocatalytic activity promoted by merely visible-light? We tried to give an answer to that question. Photocatalytic activity was assessed in the liquid- and gas-solid phase (employing rhodamine B and 4-chlorophenol, and isopropanol, respectively, as the organic substances to degrade) using a light source irradiating exclusively in the visible-range. Photocatalytic activity results in the liquid-solid phase showed that a high surface hydroxylation led to specimen with superior visible light-promoted catalytic activity – i.e. dye and ligand-to-metal charge transfer complexes sensitisation effects, not photocatalysis sensu-strictu. On the other hand, the gas-solid phase results showed that a higher amount of the absolute rutile fraction (around 10 wt%), together with less recombination of the charge carriers, were more effective for both visible-light absorption and a “real” visible-light promoted photocatalytic oxidation of isopropanol.publishe