Effect of hydrogen addition on the performance of a biogas fuelled spark ignition engine

Hydrogen was added in small amounts (5%, 10% and 15% on the energy basis) to biogas and tested in a spark ignition engine at constant speed at different equivalence ratios to study the effects on performance, emissions and combustion. Hydrogen significantly enhances the combustion rate and extends the lean limit of combustion of biogas. There is an improvement in brake thermal efficiency and brake power. However, beyond 15% hydrogen the need to retard the ignition timing to control knock does not lead to improvements at high equivalence ratios. Significant reductions in hydrocarbon levels were seen. There was no increase in nitric oxide emissions due to the use of retarded ignition timing and the presence of carbon dioxide. Peak pressures and heat release rates are lower with hydrogen addition as the ignition timing is to be retarded to avoid knock. There is a reduction in cycle-by-cycle variations in combustion with lean mixtures. On the whole 10% hydrogen addition was found to be the most suitable.     

Genetic algorithm based adaptive offloading for improving IoT device communication efficiency

Wireless Networks - Improving the communication of Internet of Things (IoT) network is a challenging task as it connects a wide-range of heterogeneous mobile devices. With an extended support from...     

Theoretical studies of a spark-ignited supercharged hydrogen engine

The power developed by a combustion engine of a given displacement when running on hydrogen is lower compared to the power developed when running on gasoline or natural gas because of the lower heating value of the hydrogen-air mixture. This drop in output exists for external mixing of hydrogen and air prior to intake valve closure. However, external mixing does not require intricate engine modifications. Supercharging is an effective method to increase the output of a hydrogen engine which uses the simple technique of external mixing of hydrogen and air. Extensive experiments to study the performance of hydrogen engines are difficult under supercharged conditions. Hence, an analytical model was developed to study the performance, fuel economy and nitric oxide (NO) emission of a supercharged spark-ignited hydrogen engine.The results of limited experimental investigations carried out by one of the authors at Aachen Technical University, West Germany have been used to verify the model predictions. The model predicts the power, fuel economy and NO emission of the supercharged spark-ignited hydrogen engine at various operating conditions. Model predictions closely compare with experimental results.     

Development of an agent-based Virtual CIM architecture for small to medium manufacturers

Today's global competitions are forcing enterprises to rely on integrated manufacturing systems to satisfy constantly changing market requirements. Whereas Small to Medium Enterprises (SMEs) often feel difficult to compete with large organisations due to having insufficient resources. By integrating resources of many partners, the SMEs can form global integrated manufacturing systems in the form of Virtual CIM (VCIM) and thus achieve a competitive edge. VCIM is a concept towards integrating globally distributed manufacturing resources across enterprise boundaries. In order to implement VCIM, this research project develops an agent-based architecture to support the integration and scheduling of distributed manufacturing resources. This architecture accommodates all agents for VCIM with a three-layered structure and permits new agents to be connected with the existing structure through the Internet when and where necessary. In this architecture, many Facilitator agents coordinate activities of manufacturing resources in a parallel manner. Meanwhile, the Facilitator agents achieve proposal messages through agent negotiation based on distributed resources’ real time information and use a backward network algorithm for shortest-path to perform optimisation for resource allocation. With these approaches, an optimised production schedule has the lowest cost as the primary criteria and the shortest production time as the secondary criteria while satisfying customer required due date/time and delivering destination.     

Metformin Enhances the Anti-Cancer Efficacy of Sorafenib via Suppressing MAPK/ERK/Stat3 Axis in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) incidence, as well as related mortality, has been steadily increasing in the USA and across the globe, partly due to the lack of effective therapeutic options for advanced HCC. Though sorafenib is considered standard-of-care for advanced HCC, it only improves median survival by a few months when compared to placebo. Sorafenib is also associated with several unpleasant side effects that often lead to early abatement of therapy. Here, we investigate whether a combination regimen including low-dose sorafenib and a non-toxic dose of anti-diabetic drug metformin can achieve effective inhibition of HCC. Indeed, combining metformin with low-dose sorafenib inhibited growth, proliferation, migration, and invasion potential of HCC cells. We observed a 5.3- and 1.9-fold increase in sub-G1 population in the combination treatment compared to sorafenib alone. We found that the combination of metformin enhanced the efficacy of sorafenib and inhibited the MAPK/ERK/Stat3 axis. Our in vivo studies corroborated the in vitro findings, and mice harboring HepG2-derived tumors showed effective tumor reduction upon treatment with low-dose sorafenib and metformin combination. This work sheds light on a therapeutic strategy aiming to augment sorafenib efficacy or dose-de-escalation that may prove beneficial in circumventing sorafenib resistance as well as minimizing related side effects.     

Performance study using natural gas,hydrogen-supplemented natural gas and hydrogen in AVL research engine

In the future, hydrogen will be required to supplement and eventually replace a rapidly diminishing natural gas resource for stationary type combustion engines. Combustion properties, knock rating, engine performance and emissions of methane (the chief constituent of natural gas) and hydrogen are different as engine fuels. In the present work, investigations were carried out to obtain data on engine performance, fuel economy and emissions, using natural gas, hydrogen-supplemented natural gas (methane) and hydrogen in AVL² research engine. Investigations were also carried out to suppress flashback and to reduce nitric oxide emissions at different operating conditions, by water induction into the hydrogen-air mixture in the intake manifold for a hydrogen fueled engine.     

Effect of nanoparticles on tensile,impact and fatigue properties of fibre reinforced plastics

Advanced composite, fibre-reinforced polymer (FRP), has been favoured for certain aerospace, military, marine and automotive applications. Polymer nanocomposites containing layered silicates have attracted much attention. These exhibit increased modulus, decreased thermal expansion coefficient, increased solvent resistance and enhanced ionic conductivity when compared to the polymer alone. Here we have developed eight different combinations of composites FRP with nanoclay (montmorillonite) by layered manufacturing techniques (LM) and measured the mechanical properties. The measurement showed that the tensile strength, impact strength and fatigue life are greatly increased. A plausible explanation for high increase of properties has also been discussed.     

A genetic algorithm and queuing theory based methodology for facilities layout problem

Facilities layout, being a significant contributor to manufacturing performance, has been studied many times over the past few decades. Existing studies are mainly based on material handling cost and have neglected several critical variations inherent in a manufacturing system. The static nature of available models has reduced the quality of the estimates of performance and led to not achieving an optimal layout. Using a queuing network model, an established tool to quantify the variations of a system and operational performance factors including work-in-process (WIP) and utilisation, can significantly help decision makers in solving a facilities layout problem. The queuing model utilised in this paper is our extension to the existing models through incorporating concurrently several operational features: availability of raw material, alternate routing of parts, effectiveness of a maintenance facility, quality of products, availability of processing tools and material handling equipment. On the other hand, a queuing model is not an optimisation tool in itself. A genetic algorithm, an effective search process for exploring a large search space, has been selected and implemented to solve the layout problem modelled with queuing theory. This combination provides a unique opportunity to consider the stochastic variations while achieving a good layout. A layout problem with unequal area facilities is considered in this paper. A good layout solution is the one which minimises the following four parameters: WIP cost, material handling cost, deviation cost, and relocation cost. Observations from experimental analysis are also reported in this paper. Our proposed methodology demonstrates that it has a potential to integrate several related decision-making problems in a unified framework.