Influence of Pressure and Temperature on the Velocity of a Turbulent Jet Flow 3D

To investigate the influence of pressure and temperature on the jet velocity of a three-dimensional flow was the main goal of this study. Using a precipitation chamber with approximate capacity of 600 mL, it was studied the thermodynamic behavior of supercritical carbon dioxide mixture, dichloromethane and grape seed extract via SAS （supercritical antisolvent process）. For the numerical solution, the Navier-Stokes equations were used along with the model of turbulence k-ε and Peng-Robinson equation of state with quadratic mixing rules of Van der Waals. The method of Chung was employed to determine the viscosity, thermal conductivity and mass diffusivity of the flow numerically solved through commercial code based on CFD （computational fluid dynamics）. Simulations for pressures between 80 bar and 160 bar and temperatures between 308.15 K and 318.15 K showed large variations in the jet velocity, an important property in the dynamic mixing process that involves the size, size distribution and particle morphology.     

On the relation between micro- and macroscopic fatigue crack growth rates in aluminum alloy AMS 7475-T7351

This paper discusses the relationship between striation spacing, i.e., the microscopic crack propagation rate, as measured in postmortem fractographic inspection of fatigue fractured surfaces, and the macroscopic crack propagation rate, i.e., da/dN, as monitored during fatigue crack growth tests. Compact tensile specimens C(T) in prevalent plane-strain conditions were extracted in LT orientation from the center of a 2-in. thick rolled plate of a SAE-AMS 7475-T7351 Al alloy. Testpieces were fatigue tested according to ASTM-E647 standard, at room temperature in a servo-hydraulic closed-loop MTS testing machine operating with the unloading elastic compliance technique. da/dN-ΔK data points were collected in the Paris’ law validity region, with crack growth rates typically ranging from 0.18 to 2.02 μm/cycle. Topographical survey was conducted on the test specimen fracture surfaces in a scanning electronic microscope in order to determine striation spacing created during the fatigue test. Macro- and micro-crack growth rates were compared and good correlation have been obtained for the data within the range of ΔK assessed in the study. Results of crack growth rates have been quantitatively evaluated in terms of fatigue life estimation.     

Evaluation of Silicon Bioavailability in Soil with Different Chemical Extractants

Silicon - This study was developed to examine the extracting power and efficiency of different methods in order to identify those that best correlate the available Si in the soil with Si uptake by...     

Distributed XML processing: Theory and applications

Basic message processing tasks, such as well-formedness checking and grammar validation, common in Web service messaging, can be off-loaded from the service providers’ own infrastructures. The traditional ways to alleviate the overhead caused by these tasks is to use firewalls and gateways. However, these single processing point solutions do not scale well. To enable effective off-loading of common processing tasks, we introduce the Prefix Automata SyStem — PASS, a middleware architecture which distributively processes XML payloads of web service SOAP messages during their routing towards Web servers. PASS is based on a network of automata, where PASS-nodes independently but cooperatively process parts of the SOAP message XML payload. PASS allows autonomous and pipelined in-network processing of XML documents, where parts of a large message payload are processed by various PASS-nodes in tandem or simultaneously. The non-blocking, non-wasteful, and autonomous operation of PASS middleware is achieved by relying on the prefix nature of basic XML processing tasks, such as well-formedness checking and DTD validation. These properties ensure minimal distributed processing management overhead. We present necessary and sufficient conditions for outsourcing XML document processing tasks to PASS, as well as provide guidelines for rendering suitable applications to be PASS processable. We demonstrate the advantages of migrating XML document processing, such as well-formedness checking, DTD parsing, and filtering to the network via event driven simulations.     

Factors that influence product life cycle management to develop greener products in the mechanical industry

Our aim was to discover the most important factors that influence the development of greener products in the mechanical industry, emphasising green design in product creation based on current environmental issues and considering product development as one important aspect of product life cycle management. This model is important to the mechanical industry because this sector relies heavily on raw materials, and recycling products is one way to improve environmental conditions. We used exploratory factor analyses to assess new product development, communication in change management, concurrent engineering, green products design worries and supplier involvement risks perception. The factor analyses initially found 10 constructs, but the 10th was eliminated because it had only one variable, and 5 were eliminated because they yielded Cronbach’s alpha values less than 0.6. To develop this model, we sent questionnaires to 2000 professionals in the Brazilian mechanical industry through LinkedIn discussion groups, mostly to professionals who participated in product development and was received 405 answered questionnaires which 394 was considered valid. The results show the importance of consistently managing product development throughout the entire product life cycle. This includes aspects such as product recycling, green products and using materials that are easy to recycle, from the very beginning of product design.     

Experimental and Numerical Investigation of a Reactive Absorption Column for Chlorine Gas Mitigation

Chlorine gas is extensively used in a variety of chemical processes as an end product or reactant, for instance, in the conversion of phthalocyanine dye. Reactive absorption (RA) columns can be applied for the treatment of the waste gas streams at the outlet of the reaction equipment, in order to satisfy the environmental regulations, and these should be prepared for potential accidents. The objective of this study was to evaluate an industrial-scale RA column for the treatment of chlorine gas stream in a phthalocyanine plant in the case of an accident. A coupled experimental and numerical study was performed. A factorial design was applied for the definition of a set of experimental conditions to be evaluated in a pilot-scale plant operated in the laboratory. The data collected were treated by means of the response surface methodology, and coupled numerical schemes allowed the determination of the mass transfer coefficient and the reaction rate constant. Finally, numerical studies were carried out to assess the industrial-scale column behavior. It was found that the industrial absorption column was able to treat a stream of chlorine at a flow rate of 900 kg/h with an efficiency of approximately 79%.