Thermal analysis of an enriched flame incinerator for aqueous residues

The use of oxygen to enrich the combustion air can be an attractive technique to increase capacity of an incinerator originally designed to operate with air. If incinerator parameters such as operation temperature, turbulence level and residence time are fixed for a certain fuel supply rate, it is possible to increase the residue consumption rate using enriched air. This paper presents the thermal analysis for operation with enriched air of an aqueous residue experimental incinerator. The auxiliary fuel was diesel oil. The theoretical results showed that there is a considerable increase in the incineration ratio up to approximately 50% of O₂ in the oxidiser. The tendency was confirmed experimentally. Thermal analysis was demonstrated to be an important tool to predict possible incinerator capacity increase.     

The reaction of 1-cyano-1-methylethyl radical with antidegradant ethoxyquin and its aminyl and nitroxide derivatives

6-Ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline (ethoxyquin, I ) does not react with the model alkyl radical, 1-cyano-1-methylethyl, in an inert atmosphere. On the other hand, its aminyl derivative ( II ) reacts readily with the model alkyl radical; the main product of this reaction is 6-ethoxy-8-(1-cyano-1-methylethyl)-2,2,4-trimethyl-1,2-dihydroquinoline ( V ), while 6-ethoxy-1-(1-cyano-1-methylethyl)-2,2,4-trimethyl-1,2-dihydroquinoline ( VI ) is formed as a by-product. 6-Ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline-N-oxyl ( III ) also effectively deactivates the model alkyl radical to form 6-ethoxy- 8-(1-cyano-1-methylethoxy)-2,2,4-trimethyl-1,2-dihydroquinoline ( X ). It follows from these results that I is an ineffective antidegradant in oxygen-free atmosphere. However, at very low oxygen concentrations, I becomes capable of deactivating alkyl radicals. Together with its ability to deactivate alkylperoxide radicals, this explains the high antifatigue activity of I . In the presence of silica gel, V is readily cyclized to 8-ethoxy-1,2,3,4-tetrahydro-2-imino-1,1,4,4,6-pentamethylpyrrolo[3,2,1-ij]quinoline ( VIII ). VI undergoes thermal decomposition into its components, i.e., aminyl II and the model radical. Photodecomposition of X on silica gel yields 6-ethoxy-2,2,4-trimethyl-8-quinolone ( XIII ).     

Collapse of a Liquid Column: Numerical Simulation and Experimental Validation

This paper is focused on the numerical and experimental analyses of the collapse of a liquid column. The measurements of the interface position in a set of experiments carried out with shampoo and water for two different initial column aspect ratios are presented together with the corresponding numerical predictions. The experimental procedure was found to provide acceptable recurrence in the observation of the interface evolution. Basic models describing some of the relevant physical aspects, e.g. wall friction and turbulence, are included in the simulations. Numerical experiments are conducted to evaluate the influence of the parameters involved in the modeling by comparing the results with the data from the measurements. The numerical predictions reasonably describe the physical trends.     

A triangular finite shell element based on a fully nonlinear shell formulation

This work presents a fully nonlinear six-parameter (3 displacements and 3 rotations) shell model for finite deformations together with a triangular shell finite element for the solution of the resulting static boundary value problem. Our approach defines energetically conjugated generalized cross-sectional stresses and strains, incorporating first-order shear deformations for an inextensible shell director (no thickness change). Finite rotations are treated by the Euler–Rodrigues formula in a very convenient way, and alternative parameterizations are also discussed herein. Condensation of the three-dimensional finite strain constitutive equations is performed by applying a mathematically consistent plane stress condition, which does not destroy the symmetry of the linearized weak form. The results are general and can be easily extended to inelastic shells once a stress integration scheme within a time step is at hand. A special displacement-based triangular shell element with 6 nodes is furthermore introduced. The element has a nonconforming linear rotation field and a compatible quadratic interpolation scheme for the displacements. Locking is not observed as the performance of the element is assessed by several numerical examples, which also illustrate the robustness of our formulation. We believe that the combination of reliable triangular shell elements with powerful mesh generators is an excellent tool for nonlinear finite element analysis.Fellowship funding from FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo) and CNPq (Conselho Nacional de Pesquisa), together with the material support and stimulating discussions in IBNM (Institut für Baumechanik und Numerische Mechanik), are gratefully acknowledged in this work.     

Vaporization Processes and Pressure Buildup during Dewatering of Dense Refractory Castables

This work describes an experimental investigation on the dewatering kinetics of high-alumina refractory bodies under several heating conditions. The drying stages involving the removal of unbound water have been correlated with the two consecutive thermal processes by which liquid water transforms into vapor during heating: evaporation and ebullition. Thermogravimetric data have been used as the basis for a discussion of the parameters that affect the performance of both vaporization processes and guide the design of suitable heating schedules aimed at minimizing the drying time and the risk of harmful pore pressurization.     

Bacterial biofilm on successful and failed orthodontic mini‐implants—a scanning electron microscopy study

Mini‐implants have been extensively used in Orthodontics as temporary bone anchorage devices. However, early failure of mini‐implants due to mobility might occur and the colonization of their surfaces by pathogenic bacteria has been referred to as one of the contributing factors. In this study, scanning electron microscopy (SEM) was used to assess the presence of microorganisms adhered to the surface of mini‐implants that failed due to loss of stability. Twelve self‐drilling titanium mini‐implants (1.6 mm diameter × 9.0 mm long) were collected from 12 patients undergoing orthodontic treatment—7 successful and 5 failed mini‐implants. The mean time of permanence in the mouth was 15.8 and 2.4 months for successful and failed mini‐implants, respectively. The devices were placed in the maxilla and/or mandible and removed by the same surgeon and were processed for SEM analysis of the presence of microorganisms on their surfaces (head, transmucosal profile, and body). Extensive bacterial colonization on mini‐implant head and transmucosal profile was observed in all successful and failed mini‐implants. None of the failed mini‐implants exhibited bacteria on its body and only one mini‐implant belonging to the successful (stable) group exhibited bacteria on its body. The results did not suggest a relationship between failure and presence of bacterial colonies on mini‐implant surfaces. Microsc. Res. Tech. 78:1112–1116, 2015. © 2015 Wiley Periodicals, Inc.     

Analysis of thermal problems in development of spent fuel transport cask for research reactors

A packaging for the transport of irradiated fuel from research reactors was designed by a group of researchers to improve the capability in the management of spent fuel elements from the reactors operated in the region. Two half scale models for MTR fuel were constructed and tested so far and a third one for both MTR and TRIGA fuels will be constructed and tested next. Four test campaigns have been carried out, covering both normal and hypothetical accident conditions of transportation. The thermal test is part of the requirements for the qualification of transportation packages for nuclear reactors spent fuel elements. In this paper, both the numerical modelling and experimental thermal tests performed are presented and discussed. The cask is briefly described as well as the finite element model developed and the main adopted hypotheses for the thermal phenomena. The results of both numerical runs and experimental tests are discussed as a tool to validate the thermal modelling. The impact limiters, attached to the cask for protection, were not modelled.     

Kinetics of Escherichia coli inactivation employing hydrogen peroxide at varying temperatures,pH and concentrations

The effectiveness of hydrogen peroxide on the destruction of planktonic cells of Escherichia coli at different temperatures, pH and sanitizer concentrations was studied. Inactivation kinetics of E. coli exhibited a clear dependence on hydrogen peroxide concentration, pH and temperature. A Weibullian mathematical model successfully described the inactivation curves. Quantitative kinetic results obtained allowed to identify various combinations H₂O₂ concentration–pH–temperature for 5-log cycles reduction of E. coli. Flow cytometry analysis revealed induced H₂O₂ cytoplasm membrane damage. TEM observations indicated that H₂O₂ treatment resulted in rupture of outer and cytoplasm membranes and a more uniform granularity.     

A conceptual modeling quality framework

The goal of any modeling activity is a complete and accurate understanding of the real-world domain, within the bounds of the problem at hand and keeping in mind the goals of the stakeholders involved. High-quality representations are critical to that understanding. This paper proposes a comprehensive Conceptual Modeling Quality Framework, bringing together two well-known quality frameworks: the framework of Lindland, Sindre, and S?lvberg (LSS) and that of Wand and Weber based on Bunge’s ontology (BWW). This framework builds upon the strengths of the LSS and BWW frameworks, bringing together and organizing the various quality cornerstones and then defining the many quality dimensions that connect one to another. It presents a unified view of conceptual modeling quality that can benefit both researchers and practitioners.     

Platform for promoting a hydrogen economy in Southwest Europe: The HYRREG project

The effective promotion of hydrogen technologies is best achieved when there is a strategy and a well defined and accepted plan for a hydrogen-based economy. The HYRREG project, funded by the Program of Cooperation of Southwest Europe (SUDOE), had as main objectives the development of a platform to generate hydrogen-related projects and a roadmap to enhance regional competitiveness and development of industry in this field in the SUDOE region which accounts for approximately 18% of the area and 12% of the population of the European Union. An analysis of the energy profiles in these regions reveals significant growth in capacity of renewable sources, principally from wind energy, yet the region has a high dependence on fossil fuels. The HYRREG consortium therefore believes that there is a good basis for supporting the development and introduction of hydrogen-based technologies in the region, especially with respect to the use of hydrogen for storage, to enhance security of supply and pave the way for a cleaner environment.