Dewpoints of flue gases for energy-recovery system design and operation

Low temperature corrosion from flue gases is a common problem in energy recovery systems. We present a simple computation procedure to estimate the dewpoint of combustion gases, which is the limiting design temperature to prevent corrosion. If the composition of fuel oil and the percentage of CO₂ or O₂ in the flue gases are known, the air ratio, percentage of H₂O, p.p.m. of SO₃ in the flue gas, and the dewpoint can be estimated with an error of 1.9%. The results indicate that the dewpoint is high because the combustion conditions are not appropriately adjusted, even if low sulfur fuel oil is used. We conclude that both the fuel quality and the combustion conditions are controlling variables in the design and operation of energy recovery systems.     

Dependence of electrical properties on interfacial layer of Ta2O5 films

The change in the thickness and chemical states of the interfacial layer and the related electrical properties in Ta₂O₅ films with different annealing temperatures were investigated. The high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy analyses revealed that the 700 °C-annealed Ta₂O₅ film remained to be amorphous and had the thinnest interfacial layer which was caused by Ta-silicate decomposition to Ta₂O₅ and SiO₂. In addition, the electrical properties were improved after annealing treatments. Our results suggest that an annealing treatment at 700 °C results in the highest capacitance and the lowest leakage current in Ta₂O₅ films due to the thinnest interfacial layer and non-crystallization.     

Bandwidth-Compensation Method for Miniaturized Parallel Coupled-Line Filters

This paper proposes a bandwidth-compensation method for miniaturized filters based on short-ended parallel coupled lines. Capacitive loading of such coupled lines is a relatively simple means of reducing the line lengths. In this study, a method is developed that predicts exactly the degree of reduction in the fractional bandwidth due to miniaturization. Using this method, the fractional bandwidth of the prototype coupled line filter can be adjusted, enabling miniaturized filters to maintain the targeted fractional bandwidth. The proposed bandwidth-compensation method applies for any type of filters with coupled lines realized with various transmission lines, with uniform or nonuniform line lengths. Experimental results are also presented that verify the validity of the method.     

Growth temperature dependence of low-noise MESFET in molecular-beam epitaxy

The substrate growth temperature dependence of electrical properties for a low-noise MESFET fabricated on MBE-grown material has been demonstrated. The optimum noise figure and its associated gain were attributed to the higher epilayer quality and mobility at a growth temperature of 650°C between temperatures of 550°C and 700°C.     

A new alloy design concept for austenitic stainless steel with tungsten modification for bipolar plate application in PEMFC

The feasibility of a new alloy design concept utilizing the principle of ‘tungsten bronze effect’ is critically evaluated for the development of metallic bipolar plates for proton exchange membrane fuel cell (PEMFC). An austenitic stainless steel (ASS) is modified with W and La to improve the stability of the passive film in an acidic environment as well as to reduce the contact resistance by the tungsten bronze effect. The experimental ASS containing W and La was evaluated in a simulated PEMFC environment of H₃PO₄ and H₂SO₄ solutions at 80 °C, and the electrical property was evaluated by performing a contact resistance test. The test results show that the ASS modified with W and La has good passive film stability for corrosion resistance and low contact resistance. The X-ray photoelectron spectroscopy (XPS) analysis clearly suggests the possibility of the tungsten bronze effect from the change in valency state of W⁶⁺ to W⁵⁺ in the passive film formed on the modified ASS. The feasibility of a new alloy design concept utilizing the ‘tungsten bronze effect’ is well demonstrated; however, more study is highly required for the development of metallic bipolar plates of PEMFC.     

Air-Oxidation Behavior of a Cu60Hf25Ti15 Bulk Metallic Glass at 375–520 °C

The oxidation behavior of a Cu₆₀Hf₂₅Ti₁₅ bulk metallic glass was studied over the temperature range of 375–520 °C in dry air. The oxidation kinetics of the amorphous alloy generally followed the parabolic law at all temperatures, with an oxidation rate increasing with temperature. The oxidation rates of the amorphous alloy were much higher than those of polycrystalline pure-Cu, implying that the additions of Hf and Ti accelerated the oxidation reaction. The composition of the scales formed on the amorphous alloy was strongly temperature-dependent, since they consisted mostly of Cu₄O₃ and CuO with minor amounts of HfO₂ at T ≤ 450 °C, while mostly CuO with minor amounts of HfO₂ and Cu₂TiO₃ were detected at higher temperatures. In addition, nanocrystalline Cu₅₁Hf₁₄ and Cu₃Ti₂ phases were detected on the substrate after oxidation at T ≥ 450 °C, indicating the occurrence of phase transformation.     

Interferon-gamma upregulates the stromelysin-1 gene expression by human skin fibroblasts in culture

Beliefs about human nature, adult education, adult learners, and moral commitment are at the heart of the educator-learner agreement. In continuing nursing education, it is the point where professional values, morals, and ethical principles meet. Using Husteds' bioethical decision-making model, the values, beliefs, and actions within the educator-learning agreement are identified and organized by the bioethical standards. By relating the bioethical standards to practice, continuing nurse educators can find their own basis for practice and work toward attaining a consistent professional ethical orientation.     

Thermodynamic assessment of the Al deoxidation reaction in liquid iron

The deoxidation reaction of aluminum in liquid iron has been investigated thermodynamically using Al₂O₃ crucible at 1873 K under Ar atmosphere as a fundamental study for the accurate control of inclusions in the ladle refining process. In addition to the equilibrium constant log K_A1 for the aluminum deoxidation reaction, the first-order and second-order interaction parameters between aluminum and oxygen were experimentally determined in the concentration range of aluminum up to 1 %. The temperature dependence of the equilibrium constant and the first-order interaction parameter e^A1 was also obtained: log K_A1 = 12.32 - 47400/T, e^A1 = 15.57 - 36500/T. The equilibrium relation between aluminum and oxygen contents in the aluminum deoxidized iron by applying interaction parameters and the equilibrium constant determined in this work satisfies fairly well the equilibrium data over the whole concentration range of aluminum considered.     

Double blind, randomised, placebo controlled study of oral vancomycin in prevention of necrotising enterocolitis in preterm, very low birthweight infants

AIMS: To evaluate the effectiveness of oral vancomycin in the prophylaxis of necrotising enterocolitis in preterm, very low birthweight infants. METHODS: A prospective, double blind, randomised, placebo controlled study in a tertiary referral centre of a university teaching hospital was conducted on 140 very low birthweight infants consecutively admitted to the neonatal unit. The babies were randomly allocated to receive oral vancomycin (15 mg/kg every 8 hours for 7 days) or an equivalent volume of placebo solution. Prophylaxis was started 24 hours before the start of oral feeds. All suspected cases of necrotising enterocolitis were investigated with a full sepsis screen and serial abdominal radiographs. Necrotising enterocolitis was diagnosed and staged according to modified Bell's criteria. RESULTS: Nine of 71 infants receiving oral vancomycin and 19 of 69 infants receiving the placebo solution developed necrotising enterocolitis (p = 0.035). Infants with necrotising enterocolitis were associated with a significant increase in mortality (p = 0.026) and longer duration of hospital stay (p = 0.002). CONCLUSIONS: Prophylactic oral vancomycin conferred protection against necrotising enterocolitis in preterm, very low birthweight infants and was associated with a 50% reduction in the incidence. However, widespread implementation of this preventive measure is not recommended, as it would only be effective in necrotising enterocolitis caused by Gram positive organisms and could increase the danger of the emergence of vancomycin resistant or dependent organisms. Its use should be restricted to a high prevalence nursery for a short and well defined period in a selected group of high risk patients.