• Applied Chemistry for Engineering
• /
• v.29 no.4
• /
• pp.468-473
• /
• 2018

In this study, the reforming reaction of vacuum residues (VR), high viscosity oil residues produced from vacuum distillation process of petroleum oil, was carried out using catalytic aquathermolysis reaction. VR showed a prone to decrease the amount of resins and asphaltenes in the constituents, and to increase saturates and aromatics when reacting with steam at 30 bar and above $300^{\circ}C$ for 24 h. When the amount of steam is not enough at this reaction, the asphaltene content in the products was rather increased after the reaction. As a result of the catalytic aquathermolysis using the metal oxide-zeolite catalyst with the decaline as a hydrogen donor, a 10% decrease in resin and asphaltene as well as a 10% increase in the aromatic hydrocarbon were observed. Consequently, the viscosity of VR decreased by 70% after the reaction. GC-Mass spectroscopy showed that the aquathermolysis of VR resulted in the decomposition of the resins and asphaltens into a low molecular weight material.

• Journal of environmental and Sanitary engineering
• /
• v.21 no.3 s.61
• /
• pp.15-26
• /
• 2006

As traffic in city-centre around the world continues to increase, so levels of atmospheric pollutants continue to rise. High concentrations of NOx can have negative effects on human health, and we must find new ways to reduce their levels in the air we breathe. Nitrogen oxide gas (NOx), consisting of nitrogen monoxide (NO) and nitrogen dioxide $(NO_2)$ produced using $O_3$ oxidation, at a low concentration corresponding to that on roads as a result of exhaust from automobiles, was carried out to evaluate the removal characteristics of NOx through a laboratory-scale biofilter packed with soil as a packing material. A mixture media (yellow soil (30%): soil (40%): compost (10%): a used briquet (20%)) was applied. After about 1day of operation, the removal efficiency for $NO_2$ in all experiments with a constant condition ($25^{\circ}C$ and water humidity (60%)) was over 98%. The retention times of the section between phase I and phase II for formation and reduction of $NO_3$ NO and $NO_2$ on the initial $NO_3$ concentration was 50min $(O_3:195\;ppb),\;55min\;(O_3:925\;ppb),\;65min\;(O_3:1743\;ppb),\;70min\;(O_3:2616\;ppb),\;75min\;(O_3:3500\;ppb)$, respectively The soil biofilter system is a unique technology that purifies urban air by utilizing the natural processes that take place in the soil. Although some of the processes are quite complex, they can broadly be summarized as adsorption onto soil particles, dissolution into soil pore water, and biochemical.

• Journal of the Korean Ceramic Society
• /
• v.37 no.2
• /
• pp.186-193
• /
• 2000

Effects of 1.0 mol% CoO addition on sintering and the electrical properties of ZnO-Bi2O3-Sb2O3(ZBS) varistor system with 3.0 mol% co-addition of Sb2O3 and Bi2O3 at various Sb/Bi ratio (0.5, 1.0, and 2.0) were investigated. Cobalt had little influence on the liquid-phase formation and the pyrochlore decomposition temepratures of ZBS, while densification was mainly dependent on Sb/Bi ratio: when Sb/Bi=0.5, excess Bi2O3 irrelevant to the formation of pyrochore(Zn2Sb3Bi3O14) forms eutectic liquid at ~75$0^{\circ}C$ which promotes densification and grain growth; with Sb/Bi=2.0, the second phase Zn7Sb2O12 formed by excess Sb2O3 irrelevant to the formation of the pyrochlore retards densification up to ~100$0^{\circ}C$. These phases caused the coarsening and uneven distribution of the second phase particles on the grain boundaries of ZnO above the pyrochlore decomposition temperature(~105$0^{\circ}C$), which led to broad size dist-ribution of ZnO; the specimen with Sb/Bi=1.0 showed homogeneous microstructure compared with the others, which enabled improved varistor characteristics. Doping of Co increased the nonlinearity and the potential barrier height of ZBS, which is thought to stem from improved sintering behavior such as homogenized microstructure due to size reduction and even distribution of the second phase and suppressed volatility of Bi2O3, as well as the improvement in the potential barrier structure via increased donor and interface electron trap densities.

• Journal of the Korean Ceramic Society
• /
• v.39 no.8
• /
• pp.769-774
• /
• 2002

The powder mixture in which Fe-Ni alloy particles of 20 nm were homogeneously dispersed on $Al_2O_3$ particle surfaces was prepared by hydrogen reduction of $Al_2O_3$ and metal oxide powders. $Al_2O_3$/Fe-Ni nanocomposites fabricated by pressureless sintering were only composed of $Al_2O_3$ and ${gamma}$-Fe-Ni phases and achieved over 98% of the theoretical density at the sintering temperature above $1350^{\circ}C$. The highest strength and toughness of the composites were 574 MPa and 3.9 MP$a{\cdot}m1/2$, respectively. These values were about 20% higher than these of monolithic $Al_2O_3$ sintered at the same conditions. Nanocomposites showed ferromagnetic properties and coercive force was increased with decrease of the average particle size of dispersions.

• Journal of Electrochemical Science and Technology
• /
• v.9 no.3
• /
• pp.202-211
• /
• 2018

In this work, Fe-Pd alloy films have been electrodeposited on different substrates using an electrolyte containing $[Pd(NH_3)_4]^{2+}$ (0.02 M) and $[Fe-Citrate]^{2+}$ (0.2 M). The influences of substrate and overpotential on chemical composition, nucleation and growth kinetics as well as the electrodeposited films morphology have been investigated using energy dispersive X-ray spectroscopy (EDS), current-time transients, scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD) patterns. In all substrates - brass, copper and sputtered fluorine doped tin oxide on glass (FTO/glass) - Fe content of the electrodeposited alloys increases by increasing the overpotential. Also the cathodic current efficiency is low due to high rate of $H_2$ co-reduction. Regarding the chronoamperometry current-time transients, it has been demonstrated that the nucleation mechanism is instantaneous with a typical three dimensional (3D) diffusion-controlled growth in the case of brass and copper substrates; while for FTO, the growth mode changes to 3D progressive. At a constant overpotential, the calculated number of active nucleation sites for metallic substrates is much higher than that of FTO/glass; however by increasing the overpotential, the number of active nucleation sites increases. The SEM micrographs as well as the XRD patterns reveal the formation of Fe-Pd alloy thin films with nanostructure arrangement and ultra-fine grains.

• The Journal of Advanced Prosthodontics
• /
• v.6 no.4
• /
• pp.272-277
• /
• 2014

PURPOSE. The purpose of this study was to investigate the impact of different surface treatment methods and thermal ageing on the bond strength of autopolymerizing acrylic resin to Co-Cr. MATERIALS AND METHODS. Co-Cr alloy specimens were divided into five groups according to the surface conditioning methods. C: No treatment; SP: flamed with the Silano-Pen device; K: airborne particle abrasion with $Al_2O_3$; Co: airborne particle abrasion with silica-coated $Al_2O_3$; KSP: flamed with the Silano-Pen device after the group K experimental protocol. Then, autopolymerized acrylic resin was applied to the treated specimen surfaces. All the groups were divided into two subgroups with the thermal cycle and water storage to determine the durability of the bond. The bond strength test was applied in an universal test machine and treated Co-Cr alloys were analyzed by scanning electron microscope (SEM). Two-way analysis of variance (ANOVA) was used to determine the significant differences among surface treatments and thermocycling. Their interactons were followed by a multiple comparison' test performed uing a post hoc Tukey HSD test (${\alpha}=.05$). RESULTS. Surface treatments significantly increased repair strengths of repair resin to Co-Cr alloy. The repair strengths of Group K, and Co significantly decreased after 6,000 cycles (P<.001). CONCLUSION. Thermocycling lead to a significant decrease in shear bond strength for air abrasion with silica-coated aluminum oxide particles. On the contrary, flaming with Silano-Pen did not cause a significant reduction in adhesion after thermocycling.

• The Journal of Advanced Prosthodontics
• /
• v.12 no.5
• /
• pp.265-272
• /
• 2020

PURPOSE. The aims of this study were to investigate mechanical properties and hydrothermal degradation behaviour of the cubic-containing translucent yttrium oxide stabilized tetragonal zirconia polycrystal (Y-TZP). MATERIALS AND METHODS. Four groups of Y-TZP (T, ST, XT, and P), containing different amount of cubic crystal, were examined. Specimens were aged by autoclaving at 122℃ under 2 bar pressure for 8 h. Phase transformation was analyzed using X-ray diffraction (XRD) to measure phase transformation (t→m). Kruskal-Wallis test was used to determine the difference. Surface hardness, biaxial flexural strength, and fracture toughness in values among the experimental groups and verified with Wilcoxon matched pairs test for hardness values and Mann Whitney U for flexural strength and fracture toughness. RESULTS. XRD analysis showed no monoclinic phase in XT and P after aging. Only Group T showed statistically significant decreases in hardness after aging. Hydrothermal aging showed a significant decrease in flexural strength and fracture toughness in group T and ST, while group XT and P showed no effect of aging on fractural strength and fracture toughness with P<.05. CONCLUSION. Hydrothermal aging caused reduction in mechanical properties such as surface hardness, biaxial flexural strength, and fracture toughness of Y-TZP zirconia. However, cubic-containing zirconia (more than 30% by volume of cubic crystal) was assumed to have high resistance to hydrothermal degradation. Clinical significance: Cubic-containing zirconia could withstand the intraoral aging condition. It could be suggested to use as a material for fabrication of esthetic dental restoration.

• Asian-Australasian Journal of Animal Sciences
• /
• v.19 no.7
• /
• pp.1040-1046
• /
• 2006

Studies were carried out with a repeated $4{\times}4$ Latin square design with eight cannulated pigs fed four experimental diets to investigate the effect of dietary fiber and starch sources on apparent ileal and fecal amino acid digestibility. Each period lasted 15 d, with diet acclimation from d 1 to 7, feces collection for 48 h on d 8 to 9 and ileal sample collection for 12 h on d 13 to 15. The four experimental diets consisted mainly of cooked rice with the addition of protein sources (CON), partial replacement of cooked rice with either potato starch (PS), sugar beet pulp (SBP) or wheat bran (WB). Chromic oxide was used as an indigestible marker. With the exception of histidine, lysine and tryptophan, no differences were observed in the apparent ileal digestibility of amino acids between diets. The inclusion of potato starch did not affect the ileal and fecal amino acid digestibility. In comparison with diet CON, a decreased (p<0.05) ileal digestibility of histidine was found in pigs fed diet SBP, while the ileal digestibilities of histidine, lysine and tryptophan were decreased (p<0.05) by the inclusion of wheat bran. Inclusion of fiber sources (sugar beet pulp and wheat bran) caused a reduction (p<0.05) in the fecal amino acid digestibility and the net disappearance of amino acids in the large intestine. Of the indispensable amino acids, there was a 'net synthesis' for methionine in the large intestine of pigs when diets were supplemented with dietary fiber. The decrease in fecal amino acid digestibility with the addition of dietary fiber indicates an increase in the synthesis of bacterial protein in the large intestine.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.5
• /
• pp.2845-2850
• /
• 2013

Background: Breast cancer is one of the most frequent diseases in women today. Little information exists on modifiable lifestyle factors including effects of ginger supplements (as an anti-oxidant and anti-inflammatory herbal) and water-based exercise on biomarkers related to oxidative stress such as malondialdehyde (MDA), nitric oxide (NO) and glutathione peroxidase (GPx) and adiponectin in obese women with breast cancer. The aim of this study was to determine the single and concomitant effect of 6-wks water-based exercise and oral ginger supplement on the aforesaid markers in obese women with breast cancer. Materials and Methods: Forty women diagnosed with breast cancer ($48{\pm}5.4$ years, $76{\pm}9$ kg, fat mass $41.8{\pm}4%$), volunteered to participate in the study. Subjects were randomly assigned into four groups; placebo, water-based exercise, ginger supplement and water-based exercise+ginger supplement groups. Subjects in the ginger supplement group and the water-based exercise+ginger supplement group orally received 4 capsules (each capsule contained 750 mg), 7 days a week for 6 weeks. The water-based exercise program featured progressive increase in intensity and time, ranging from 50% to 75% of heart rate reserve, in a pool with 15 meters width, 4 times a week for 6 weeks. Fasting blood samples were collected at pre-test and post-test time points. Results: The ginger supplementation and or the water-base exercise resulted in an increase of adiponectin, NO and GPx and reduction MDA, as compared to pre-test values. However, the combined intervention (water-base exercise and ginger supplement) group showed significantly a far better effect on the biomarkers related to oxidative stress and adiponectin levels, as compared to the waterbase exercise or ginger supplement alone groups and the age-matched placebo group. Conclusions: Our results revealed that water-base exercise is a non-drug therapeutic strategy to reduce systemic stress in obese women suffering from breast cancer. Further, ginger supplementation alone or in combination with training, also play an important role in the pathogenesis of oxidative stress in obese women diagnosed with breast cancer.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
• /
• v.12
• /
• pp.587-613
• /
• 1999

Environmental problems such as global climate change, depletion, ocean and air pollution, and resource degradation-compounded by an expanding world population-respect no border and threaten the health, prosperity and jobs of all mankind. Our efforts to promote democracy, free trade, and stability in the world will fall short unless people have a livable environment. We have an enormous stake in the management of the world's resources. By increasing demand for timber, natural gas, coal and consumer's goods have destroyed the grounds for living. Greenhouse gas emissions anywhere in the world have threatened coastal communities, and then changed the Earth's climate system. The burning of coal, oil, and other fossil fuels is increasing substantially the concentration of heat-trapping gasses such as carbon dioxide, methane, and nitrous oxide in our air. The earth's temperature and sea levels are rising as a result. Since 1972 there has been a marked growth in the number and scope of environmental treaties. In particular, after the 1992 Rio Conference, international legal instruments became more concentrated on addressing environment within the context of sustainable development and incorporated a number of new concepts and innovative approaches. A preliminary analysis of recent conventions and in particular those associated with the Rio Conference indicates various ideas, concepts and principles which have come to the fore including sustainable development, equity, common concern of humankind, common but differentiated responsibilities and global partnership. However, international trade also has an environmental impact which must be minimized or countered. Positive measures are to be preferred to achieve environmental goals, but where trade provisions are necessary, they should be appropriately used within environmental conventions to facilitate the reduction and limitation of the negative impacts of trade and to enhance the complementarity of the multilateral trade regime with the imperatives of environmental protection, in the interests of environmental protection and sustainable development generally. The international community has to recognize and endorse this need to achieve complementarity between trade and environment issues.