Heat Removal from Reverse Flow Reactors Used in Methane Combustion

The idea of using Reverse Flow Reactors (RFR) for methane reduction in exhausts has been well elucidated in the past. However, there are intricacies in such operations to maintain the ignited state of the reactor along with maintaining low outlet concentrations of methane. This is especially true under rich feed conditions where combustion reactions liberate more heat leading to possible catalyst deactivation. Under favourable conditions, it is possible to continuously extract heat from the RFR system‐this is a viable way of maintaining acceptable thermal conditions in the reactor and consequently retaining catalyst activity. This paper elaborates upon the optimal amount of heat that can be removed from the system without losing the sustainability while preventing overheating of the catalyst bed. A simple event based control strategy is implemented for switching the inlet and outlet ports (flow reversal). Issues relating to the operation of reverse flow reactors with side feeding and the possibility of extraction of useful heat from such systems are also discussed. Methane combustion reaction and a continuous two dimensional heterogeneous model of the reactor have been employed in this study.     

An agent-based information architecture for shop-floor control

The principal aim of this paper is to develop a highly flexible shop-floor control system architecture using software agents which communicate with one another using the peer-to-peer paradigm. A shop-floor control system is responsible for the coordination of material and information flow in the manufacturing system as well as for communicating with the suppliers and the distributors or customers. It has to make several dynamic decisions like release of parts into the system, scheduling and routing of parts and transportation, machine selection, rerouting in case of failures etc. In our proposed control system such decisions are made bysoftware agents which are equipped with local databases and independent computing power and a reliable communication interface. The different agencies and agents that make up the control system are discussed in this paper. In this proposed system, a part agent (as part of the part agency) enters the factory floor with process requirements, contacts the task assignment agent for the process plan, the monitoring agent for the status of the system, the scheduling agent for the detailed schedule, and the router agent for transportation before finally proceeding to get served. Mechanisms for handling issues like scheduling, routing, and failures have been discussed. Java and its underlying programming concepts form the backbone of our agent architecture. Agents use KQML (knowledge query and manipulative language) constructs for sending queries and KIF (knowledge interchange format) constructs for representing knowledge and exchanging information. Our system has several advantages over other control architectures and it is highly likely that future factory floor control systems will follow similar paradigms.     

FROM DATABASE TO OPERATION DESIGN USING A MULTIPLE MODEL APPROACH

We address the problem of estimating the input conditions (mixture compositions, operating temperature, pressure, etc.) that will result in manufacturing a product with the required properties using a data-based approach. A single-model type paradigm is shown to be unsuitable for all data sets or even for all output variables in a particular data set. A multiple-model type paradigm is therefore advocated. The input-output map is first obtained using one or more of the several modeling approaches. These models are then inverted to suggest operational strategies that will meet production goals. Several examples are presented to demonstrate the efficacy of the proposed methodology.     

Deformation processes in ZE41A cast magnesium alloy investigated by the acoustic emission technique

The acoustic emission (AE) technique is a very useful tool to detect the microplastic yielding occurring during macroscopic deformation. Cast ZE14A magnesium alloy was deformed in tension at temperatures between 20 and 350 °C and at a constant strain rate of 0.05 s⁻¹. Measurements of the AE during testing are presented and related to the microstructure of the sample material. AE count rates increase with increasing temperature from room temperature to a maximum at 330 °C. Above 330 °C temperatures count rate decrease. This behaviour is discussed with a view to the role of heat treatment, twinning and deformation mechanism.     

Characteristics of Laser Beam and Friction Stir Welded AISI 409M Ferritic Stainless Steel Joints

This article presents the comparative evaluation of microstructural features and mechanical properties of friction stir welded (solid-state) and laser beam welded (high energy density fusion welding) AISI 409M grade ferritic stainless steel joints. Optical microscopy, microhardness testing, transverse tensile, and impact tests were performed. The coarse ferrite grains in the base material were changed to fine grains consisting duplex structure of ferrite and martensite due to the rapid cooling rate and high strain induced by severe plastic deformation caused by frictional stirring. On the other hand, columnar dendritic grain structure was observed in fusion zone of laser beam welded joints. Tensile testing indicates overmatching of the weld metal relative to the base metal irrespective of the welding processes used. The LBW joint exhibited superior impact toughness compared to the FSW joint.     

Microstructure,Tensile and Impact Toughness Properties of Friction Stir Welded Mild Steel

 Microstructure, tensile and impact toughness properties and fracture location of friction stir welded AISI 1018 mild steel are revealed in this paper. The 5 mm thick AISI 1018 mild steel plates were friction stir welded with tool rotational speed of 1000 rpm and welding speed of 50 mm/min with tungsten base alloy tool. Tensile strength of stir zone is higher (8%) when compared to the base metal. This may be due to the formation of finer grains in the weld nugget region under the stirring action of the rotating tool. The ductility and impact toughness of the joints are decreased compared to the base metal and this is due to the inclusion of tungsten particles in the weld region.     

Evaluation of Microstructure and Mechanical Properties of Laser Beam Welded AISI 409M Grade Ferritic Stainless Steel

 The microstructure analysis and mechanical properties evaluation of laser beam welded AISI 409M ferritic stainless steel joints are investigated. Single pass autogeneous welds free of volumetric defects were produced at a welding speed of 3000 mm/min. The joints were subjected to optical microscope, scanning electron fractographe, microhardness, transverse and longitudinal tensile, bend and charpy impact toughness testing. The coarse ferrite grains in the base metal were changed into dendritic grains as a result of rapid solidification of laser beam welds. Tensile testing indicates overmatching of the weld metal is relative to the base metal. The joints also exhibited acceptable impact toughness and bend strength properties.     

Optimization of chemotherapy and immunotherapy: In silico analysis using pharmacokinetic–pharmacodynamic and tumor growth models

Chemotherapy is one of the most prominent cancer treatment modalities. However, it is not always a comprehensive solution for tumor regression. This led to the advent of novel strategies to combine chemotherapy with other emerging therapies to treat cancer patients keeping side effects to a minimum. In this work, the focus is on the optimization of chemotherapy using doxorubicin and its combination with adoptive-cell-transfer therapy which is one of the schemes of immunotherapy. The key challenge in the combination therapy is to find the sequence, timing and the dosage of therapies for a given patient. In this regard, an in silico pharmacokinetic/pharmacodynamic model describing the interaction between tumor cells, immune cells and doxorubicin is used to formulate a multi-objective optimization problem by considering clinically relevant objectives and constraints. Then, the multi-objective optimization problem is solved using genetic algorithm and the results obtained for the different cases are compared to discover a therapeutically efficacious treatment regimen. And the metrics used to compare different cases are final tumor size and tumor relapse time. The comparison between chemotherapy alone and its combination with immunotherapy shows that combination therapy is effective in controlling the tumor growth.