Application of exhaust gas fuel reforming in diesel and homogeneous charge compression ignition (HCCI) engines fuelled with biofuels

This is the post-print version of the final paper published in Energy. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2007 Elsevier B.V.This paper documents the application of exhaust gas fuel reforming of two alternative fuels, biodiesel and bioethanol, in internal combustion engines. The exhaust gas fuel reforming process is a method of on-board production of hydrogen-rich gas by catalytic reaction of fuel and engine exhaust gas. The benefits of exhaust gas fuel reforming have been demonstrated by adding simulated reformed gas to a diesel engine fuelled by a mixture of 50% ultra low sulphur diesel (ULSD) and 50% rapeseed methyl ester (RME) as well as to a homogeneous charge compression ignition (HCCI) engine fuelled by bioethanol. In the case of the biodiesel fuelled engine, a reduction of NOx emissions was achieved without considerable smoke increase. In the case of the bioethanol fuelled HCCI engine, the engine tolerance to exhaust gas recirculation (EGR) was extended and hence the typically high pressure rise rates of HCCI engines, associated with intense combustion noise, were reduced

Improving gasoline direct injection (GDI) engine efficiency and emissions with hydrogen from exhaust gas fuel reforming

Exhaust gas fuel reforming has been identified as a thermochemical energy recovery technology with potential to improve gasoline engine efficiency, and thereby reduce CO2 in addition to other gaseous and particulate matter (PM) emissions. The principle relies on achieving energy recovery from the hot exhaust stream by endothermic catalytic reforming of gasoline and a fraction of the engine exhaust gas. The hydrogen-rich reformate has higher enthalpy than the gasoline fed to the reformer and is recirculated to the intake manifold, i.e. reformed exhaust gas recirculation (REGR). The REGR system was simulated by supplying hydrogen and carbon monoxide (CO) into a conventional EGR system. The hydrogen and CO concentrations in the REGR stream were selected to be achievable in practice at typical gasoline exhaust temperatures. Emphasis was placed on comparing REGR to the baseline gasoline engine, and also to conventional EGR. The results demonstrate the potential of REGR to simultaneously increase thermal efficiency, reduce gaseous emissions and decrease PM formation

Thermochemical recovery technology for improved modern engine fuel economy – part 1: analysis of a prototype exhaust gas fuel reformer

Exhaust gas fuel reforming has the potential to improve the thermal efficiency of internal combustion engines, as well as simultaneously reduce gaseous and particulate emissions.</p

Filtered EGR – a step towards an improved NOX/soot trade-off for DPF regeneration

Exhaust gas recirculation (EGR) is currently widely used in commercial diesel engines to provide an effective solution in reducing the levels of nitrogen oxide (NOX) emissions. However, this currently comes at the expense of an exponential increase in particulate matter (PM) emissions resulting directly from the dilution effect (i.e. reduction in oxygen availability), as well as a further penalty arising from the recirculation of the exhaust emissions such as soot and hydrocarbons. In our earlier work it was observed that filtered EGR (FEGR) was able to play a significant role in controlling the soot recirculation penalty and thus improve the overall NOX/soot trade-off. In order to further our understanding of the effect of recirculated exhaust gases and in particular recirculated soot and hydrocarbon (HC), comparisons were made between standard EGR, FEGR and pure nitrogen (N2), a direct cleaner replacement of the exhaust gas. When implementing FEGR, a diesel oxidation catalyst (DOC) and diesel particulate filter (DPF) were introduced into the exhaust to not only filter the soot particulates but reduce the recirculation of HC which can play a role in particulate surface growth. It was observed that the recirculated HC species and soot particles (especially at high load and EGR ratios) play a role in promoting the production and growth of further particles within the combustion chamber. Similarly, by comparing at the same O2 intake concentration as that of FEGR and introducing N2 as the EGR replacement gas, it was possible to correlate the increase in engine-out mass of soot with EGR to the recirculation of soot particles, HC species as well as the presence of H2O and CO2

Effects of diet consistency on mandibular growth. A review

Το παρόν άρθρο είναι μια ανασκόπηση που διαπραγματεύεται την επίδραση της σύστασης της διατροφής στην μορφολογία της κάτω γνάθου. Πολλές δημοσιευμένες εργασίες έχουν επικεντρωθεί στη μελέτη της σχέσης της μασητικής λειτουργίας και της αύξησης της κάτω γνάθου, εξαιτίας της θεώρησης ότι η αύξηση της κάτω γνάθου εξαρτάται απο τις φορτίσεις που ασκούνται απο τους μασητήριους μύες. Επιπρόσθετα ο σύγχρονος τρόπος διατροφής με μαλακές τροφές έχει ενοχοποιηθεί για την αύξηση των ορθοδοντικών ανωμαλιών. Ακόμα και στους επίμυς η διατροφή με μαλακή τροφή θεωρείται ένας απο τους παράγοντες που συντελεί σε ανωμαλίες της σύγκλεισης. Όλες οι δημοσιευμένες εργασίες είναι πειραματικές, κυρίως σε τρωκτικά ζώα, επειδή είναι αδύνατον να εφαρμοσθούν ανάλογες μελέτες σε ανθρώπους σε σύντομο χρονικό διάστημα. Οι περισσότερες πειραματικές μελέτες συμπεραίνουν πως οι μασητικές φορτίσεις επηρεάζουν την οστική μάζα, τη ποσότητα του οστού, τη πυκνότητα του οστού, το μήκος και το πλάτος του οστού, το βαθμό της επιμετάλωσης, την γενετική έκφραση, και την ανοσοιστοχημική αντίδραση του κολλαγόνου, όπως και τη δράση των χονδροκυττάρων στο χόνδρο του κονδύλου της κάτω γνάθου. Έχει διατυπωθεί πως το βάρος και η πυκνότητα των γνάθων επίμυων που είχαν διατραφεί με μαλακή τροφή ήταν μικρότερα απο τα αντίστοιχα των ζώων που είχαν διατραφεί με σκληρή τροφή. Επίσης οι γνάθοι και οι κόνδυλοι επίμυων που έχουν διατραφεί με μαλακή τροφή ήταν μικρότεροι σε μέγεθος και παρουσιάζουν μικρότερη πυκνότητα σε σύγκριση με τις γνάθους και τους κονδύλους των ζώων ελέγχου. Επιπρόσθετα το μήκος και το πλάτος των κονδύλων των ζώων που είχαν διατραφεί με μαλακή τροφή ήταν μικρότερα απο τα αντίστοιχα των κονδύλων των ζώων που είχαν διατραφεί με σκληρή τροφή. Η μαλακή διατροφή διαπιστώθηκε ότι επηρεάζει τέλος το βαθμό επιμετάλλωσης όπως και τη δράση των χονδροκυττάρων στο χόνδρο.This article is a review that focuses on the diet consistency and how this affects mandibular morphology. Various published studies focused on the relationship between mastication and growth of the mandible because it is considered that mandibular growth is dependent on the loads exerted by the function of the masticatory muscles. Moreover it has been pointed out that the increase of orthodontic anomalies is due to the modern softer diet. Even in rats, soft diet is one of the factors causing malocclusions. All of the studies have been experimental, mainly in rodents, since this research is impossible to be applied on humans in a short period of time. Most experimental studies suggested that occlusal loading affects bone mass, bone amount, bone density, the length and the width of the bone, the degree of mineralization, the genetic expression, the collagen immunoreaction and the chondrocytes action on the cartilage. It is stated that bone volumes and thickness of the mandible of rats fed with soft diet were smaller when compared to animals fed with hard diet. Also the mandibles and condyles were smaller and less dense in the rats of soft diet as compared to controls. Furthermore the length and the width of the condyle in the soft diet group of animals were smaller as compared to the condyle of the hard diet group of animals. Soft diets affect also the degree of mineralization, and the action of the chondrocytes on the cartilage

Sustainable supply chain management in the digitalisation era: The impact of Automated Guided Vehicles

Internationalization of markets and climate change introduce multifaceted challenges for modern supply chain (SC) management in the today's digitalisation era. On the other hand, Automated Guided Vehicle (AGV) systems have reached an age of maturity that allows for their utilization towards tackling dynamic market conditions and aligning SC management focus with sustainability considerations. However, extant research only myopically tackles the sustainability potential of AGVs, focusing more on addressing network optimization problems and less on developing integrated and systematic methodological approaches for promoting economic, environmental and social sustainability. To that end, the present study provides a critical taxonomy of key decisions for facilitating the adoption of AGV systems into SC design and planning, as these are mapped on the relevant strategic, tactical and operational levels of the natural hierarchy. We then propose the Sustainable Supply Chain Cube (S2C2), a conceptual tool that integrates sustainable SC management with the proposed hierarchical decision-making framework for AGVs. Market opportunities and the potential of integrating AGVs into a SC context with the use of the S2C2 tool are further discussed

The emerging role of water footprint in supply chain management: A critical literature synthesis and a hierarchical decision-making framework

Freshwater overexploitation and scarcity have led to extensive shifts in demand patterns for water-friendly products. As several agricultural and industrial activities are closely intertwined with water consumption, the availability of sufficient freshwater resources constitutes a significant precondition for covering global consumer needs. In this context, the design and management of sustainable supply chains in terms of freshwater resources' preservation have emerged as major challenges in the corporate agenda. As such, the concept of water footprint as a key performance indicator of freshwater utilization has been introduced at national, corporate and product levels. In this manuscript, we first provide a critical literature synthesis concerning product water footprint assessment in order to map the state-of-the-art research related to freshwater consumption and pollution in the agricultural and industrial sectors. Our analysis demonstrates that although water footprint assessment is a rapidly evolving research field, scientific publications focusing on a holistic approach concerning freshwater exploitation at a supply chain extent are rather limited. The findings further verify that the agrifood sector dominates global water use. In this respect, we analyse both corporate and academic literature in order to identify emerging issues on freshwater resources' management for agrifood products. Finally, we propose a first-effort hierarchical decision-making framework that includes water footprint mitigation policies for agrifood supply chains in order to support all stakeholders in developing a comprehensive water stewardship strategy.Public Benefit Foundation Alexander S. Onassis, European Community 7th Framework Programme (FP7-REGPOT- 2012-2013-1) GREEN-AgriChains project (Grant ID: 316167

Manipulating modern diesel engine particulate emission characteristics through butanol fuel blending and fuel injection strategies for efficient diesel oxidation catalysts

Decoupling the dependences between emission reduction technologies and engine fuel economy in order to improve them both simultaneously has been proven a major challenge for the vehicle research communities. Additionally, the lower exhaust gas temperatures associated with the modern and future generation internal combustion engines are challenging the performance of road transport environmental catalysts. Studying how fuel properties and fuel injection strategies affect the combustion characteristics, emissions formation and hence catalysts performance can unveil synergies that can benefit vehicle emissions and fuel economy and as well as guide the design of next generation sustainable fuels. The experimental work presented here was conducted using a modern single-cylinder, common rail fuel injection system diesel engine equipped with a diesel oxidation catalyst (DOC). The impact of the fuel post-injection strategy that is commonly used as part of the aftertreatment system function (i.e. regeneration of diesel particulate filters or activity in hydrocarbon selective reduction of NOX), combined with butanol-diesel fuel blend (B20) combustion on engine emissions formation, particulate matter characteristics (size distribution, morphology and structure) and oxidation catalyst activity were studied. It was found that post-injection produced lower PM concentration and modified the soot morphological parameters by reducing the number of primary particles (npo), the radius of gyration (Rg), and the fractal dimension (Df). The results were compared with the engine operation on diesel fuel. The increased concentration of HC and CO in the exhaust as a result of the diesel fuel post-injection at the studied exhaust conditions (i.e. T = 300 °C) led in the reduction of the DOC activity due to the increased competition of species for active sites. This effect was improved the combustion of B20 when compared to diesel.Publisher Statement: NOTICE: this is the author’s version of a work that was accepted for publication in Applied Energy. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Applied Energy, [190, (2017)] DOI: 10.1016/j.apenergy.2016.12.102© 2017, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/<br/

Mobile robotics in agricultural operations: A narrative review on planning aspects

The advent of mobile robots in agriculture has signaled a digital transformation with new automation technologies optimize a range of labor-intensive, resources-demanding, and time-consuming agri-field operations. To that end a generally accepted technical lexicon for mobile robots is lacking as pertinent terms are often used interchangeably. This creates confusion among research and practice stakeholders. In addition, a consistent definition of planning attributes in automated agricultural operations is still missing as relevant research is sparse. In this regard, a “narrative” review was adopted (1) to provide the basic terminology over technical aspects of mobile robots used in autonomous operations and (2) assess fundamental planning aspects of mobile robots in agricultural environments. Based on the synthesized evidence from extant studies, seven planning attributes have been included: (i) high-level control-specific attributes, which include reasoning architecture, the world model, and planning level, (ii) operation-specific attributes, which include locomotion–task connection and capacity constraints, and (iii) physical robot-specific attributes, which include vehicle configuration and vehicle kinematics.</jats:p