139 research outputs found

    Fireside Corrosion in Oxy-Fuel Combustion of Coal

    Get PDF
    Oxy-fuel combustion is based on burning fossil fuels in a mixture of recirculated flue gas and oxygen, rather than in air. An optimized oxy-combustion power plant will have ultra-low emissions since the flue gas that results from oxy-fuel combustion consists almost entirely of CO2 and water vapor. Once the water vapor is condensed, it is relatively easy to sequester the CO2 so that it does not escape into the atmosphere. A variety of laboratory tests comparing air-firing to oxy-firing conditions, and tests examining specific simpler combinations of oxidants, were conducted at 650-700 C. Alloys studied included model Fe-Cr and Ni-Cr alloys, commercial ferritic steels, austenitic steels, and nickel base superalloys. The observed corrosion behavior shows accelerated corrosion even with sulfate additions that remain solid at the tested temperatures, encapsulation of ash components in outer iron oxide scales, and a differentiation between oxy-fuel combustion flue gas recirculation choices

    Multi-layered Ruthenium-modified Bond Coats for Thermal Barrier Coatings

    Get PDF
    Diffusional approaches for fabrication of multi-layered Ru-modified bond coats for thermal barrier coatings have been developed via low activity chemical vapor deposition and high activity pack aluminization. Both processes yield bond coats comprising two distinct B2 layers, based on NiAl and RuAl, however, the position of these layers relative to the bond coat surface is reversed when switching processes. The structural evolution of each coating at various stages of the fabrication process has been and subsequent cyclic oxidation is presented, and the relevant interdiffusion and phase equilibria issues in are discussed. Evaluation of the oxidation behavior of these Ru-modified bond coat structures reveals that each B2 interlayer arrangement leads to the formation of α-Al 2 O 3 TGO at 1100°C, but the durability of the TGO is somewhat different and in need of further improvement in both cases

    Research approvals iceberg: how a 'low-key' study in England needed 89 professionals to approve it and how we can do better.

    Get PDF
    BACKGROUND: The red tape and delays around research ethics and governance approvals frequently frustrate researchers yet, as the lesser of two evils, are largely accepted as unavoidable. Here we quantify aspects of the research ethics and governance approvals for one interview- and questionnaire-based study conducted in England which used the National Health Service (NHS) procedures and the electronic Integrated Research Application System (IRAS). We demonstrate the enormous impact of existing approvals processes on costs of studies, including opportunity costs to focus on the substantive research, and suggest directions for radical system change. MAIN TEXT: We have recorded 491 exchanges with 89 individuals involved in research ethics and governance approvals, generating 193 pages of email text excluding attachments. These are conservative estimates (e.g. only records of the research associate were used). The exchanges were conducted outside IRAS, expected to be the platform where all necessary documents are provided and questions addressed. Importantly, the figures exclude the actual work of preparing the ethics documentation (such as the ethics application, information sheets and consent forms). We propose six areas of work to enable system change: 1. Support the development of a broad range of customised research ethics and governance templates to complement generic, typically clinical trials orientated, ones; 2. Develop more sophisticated and flexible frameworks for study classification; 3. Link with associated processes for assessment, feedback, monitoring and reporting, such as ones involving funders and patient and public involvement groups; 4. Invest in a new generation IT infrastructure; 5. Enhance system capacity through increasing online reviewer participation and training; and 6. Encourage researchers to quantify the approvals processes for their studies. CONCLUSION: Ethics and governance approvals are burdensome for historical reasons and not because of the nature of the task. There are many opportunities to improve their efficiency and analytic depth in an age of innovation, increased connectivity and distributed working. If we continue to work under current systems, we are perpetuating, paradoxically, an unethical system of research approvals by virtue of its wastefulness and impoverished ethical debate

    Effect of sonic versus ultrasonic activation on aqueous solution penetration in root canal dentin.

    Full text link

    Evaluation of oxidative stress markers in type-2 diabetic rat kidney with treated Delta(9)-THC

    No full text
    FEBS EMBO 2014 Conference -- AUG 30-SEP 04, 2014 -- Paris, FRANCEWOS: 000359666801155…FEBS, EMB

    Trans-sternal cardiac injury caused by a hooked needle

    No full text
    Cardiac injuries remain the most challenging of all injuries seen in the field of trauma surgery. Penetrating injury to the heart generally occurs less frequently than blunt injury and most commonly injures the large anterior right ventricle. We present an unusual, and to our knowledge a previously unreported, cause of cardiac penetrating trauma in a child, involving a hooked needle ( a 15 cm long, metallic device usually used for crocheting or lacemaking). A ventricular septal defect was managed conservatively shortly after the primary cardiorrhaphy. Evaluation methods for this rare presentation and its possible surgical treatments are discussed

    Can endoscopic injection of epinephrine prevent surgery in gastroduodenal ulcer bleeding? An analysis of 107 cases

    No full text
    Background: Gastroduodenal ulcers are still a common cause of severe upper gastrointestinal bleeding. Endoscopy has gained popularity worldwide over conventional open surgery for the treatment of upper gastrointestinal bleeding. This study aims to assess the efficacy of endoscopic injection of epinephrine in the treatment of gastroduodenal ulcer bleeding
    corecore