69 research outputs found
The return of the abject: a psychoanalytic analysis of a selection of William Shakespeare’s plays in the light of Julia Kristeva’s theories of the mind
The present research deals with the application of Julia Kristeva s psychoanalytic theories of the mind to a selection of William Shakespeare s plays. Kristeva s key psychoanalytic terms the symbolic, the semiotic and the abject are first elaborated in detail and are then applied to different situations and characters in the plays. The plays discussed in this thesis are A Midsummer Night s Dream, As You Like It and The Taming of the Shrew for the comedy section, Richard II, 1 & 2 Henry IV and Coriolanus for the English and Roman History section, and Romeo and Juliet, Macbeth and King Lear for the Tragedy section. The reason for choosing the above plays is that I believe there is a gap of knowledge in this regard and no thorough research on this scale has been conducted up to this time. The intention is to discuss and explicate the moments in which the dramatic heroes undergo some unconscious-driven experiences that can be best explained by Kristeva s post-Freudian psychoanalytic approach. In short, what I am going to show in the present study is the psychoanalytic assumption that Shakespearean characters, forced by internal or external elements, leave the symbolic and take refuge in the semiotic. In such moments, the characters inevitably face the abject which is an archaic memory comprising the elements of enchantment and horror. The abject can be best described as the archaic memories of a distant past when the self had no border and was associated with the semiotic, a subject s harmonious beginning. In its early childhood, to become a subject, an individual breaks its semiotic ties and, by so doing, enters the realm of the symbolic which is associated with grammar and law. The symbolic awards a subject a distinct identity and helps it stay on the route to signification. Kristeva s understanding of the process of individuation is explained by her subject in process , a journey in which a subject always oscillates between the symbolic and the semiotic. The key point in Kristeva s psychoanalytic thought is that the semiotic does not fade away and hovers around a subject s border of identity and remains a constant threat for its symbolic identity. To remain immune from the annihilating forces of the semiotic, a subject has to remain vigilant and protect its borders of identity. My main goal in this thesis is to show that, in some particular situations in the plays, Shakespearean characters fail to remain vigilant and, inevitably, their subjects are exposed to the abject. In other words, in moments of ambition, anger, love or fear, they surrender or take refuge in the semiotic and face the abject. Although Shakespearean plays have previously been approached by Sigmund Freud s (and some other major practitioners ) theories, the application of Kristeva s psychoanalytic theories of the mind gives the opportunity to approach the plays from a new perspective that would otherwise have remained unknown. Thus, the originality of this research lies in its extensive application of Kristeva s theories to the selected Shakespearean plays, theories that, although they derive from those of Freud, have the potential to shed light on those psychoanalytic aspects of the plays that Freud either neglected or left unfinished
Effect of natural gas direct injection (NGDI) on the performance and knock behavior of an SI engine
The unique properties of natural gas (NG), including high availability and lower cost compared with other fossil fuels, make it attractive in internal combustion engine (ICE) application. NG is composed mainly of methane and has greater knock resistance than gasoline, enabling higher compression ratios (CR). In contrast with the distinctive advantages, the NG fueled engines suffer from lower power and torque outputs. To address the subject, this study proposes an approach employing NG direct injection (NGDI) strategy (with higher volumetric efficiency unlike port injection), enabling a higher CR irrespective of knock limit. This work applies reactive computational fluid dynamics (CFD) to investigate spark ignited co-combustion of direct-injected NG with port-admitted gasoline. The results are validated against experimental data. In all simulated cases, the equivalence ratio (i.e., ∅ = 1) and the total input energy are kept constant. Engine performance is evaluated for three CRs (10.5, 11.5, and 12.5:1), five proportion of CNG (RCNG) and at part- and full-load conditions at an engine speed of 1500 rpm. Results indicated that while running RCNG = 100 % with a CR of 10.5:1, carbon monoxide (CO) and carbon dioxide (CO2) emissions were decreased by 29.3 % and 23.5 % respectively, compared to RCNG = 0 %. The corresponding emission reduction at CR = 11.5:1 was 27.1 % and 24 %; at CR = 12.5:1 they were 29.6 % and 23.5 % respectively. At each CR, the knock intensity at full load fell significantly as the percentage of NG increased. At a CR of 12.5:1, ringing intensity (RI) at full load decreased by 88.6 % when using RCNG = 100 %, instead of RCNG = 0 %. Under the same conditions, RCNG = 25 % cut RI by 56 %.© 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).fi=vertaisarvioitu|en=peerReviewed
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Combustion and Emission Enhancement of a Spark Ignition Two-Stroke Cycle Engine Utilizing Internal and External EGR Approach at Low-Load Operation
Two-stroke cycle engines have always been prominent due to their distinctive advantage incorporating high power-to-weight ratio, however the drawbacks are poor combustion efficiency, fuel short-circuiting and excessive emission of uHC and CO. These problems are apparent at low-load and speed regions and are the major obstacle to their global acceptance. The deficiencies can be addressed by increasing the in-cylinder average charge temperature employing Exhaust Gas Recirculation (EGR). An experimental study is conducted to investigate the influence of utilizing EGR techniques, including Internal and External EGR, on combustion misfiring occurrence, combustion stability and exhaust emissions using a single cylinder two-stroke SI engine at idling, low and mid-load conditions. From the results, it is observed since the average in-cylinder charge temperature is increased, due to utilizing EGRs, engine’s low and mid-load irregular combustions (misfire) and exhaust emissions are remarkably supressed and almost all of misfire cycles eliminated depending on the percentage of EGRs. In terms of combustion stability, it is agreed in general the application of EGRs improves the cyclic variation of IMEP, Pmax and CA10 compared to conventional operation. However, applying Ex-EGR compared to In-EGR will deteriorate cyclic variability of IMEP and CA10.The authors would like to acknowledge the Universiti Teknologi Malaysia (UTM) for financial support under the research university grant Q.J130000.3509.06G97
A Comparative Study of the Effect of Turbocompounding and ORC Waste Heat Recovery Systems on the Performance of a Turbocharged Heavy-Duty Diesel Engine
In this study the influence of utilization of two Waste Heat Recovery (WHR) strategies,
namely organic Rankine cycle (ORC) and turbocompounding, have been investigated based on
the performance of a heavy-duty diesel engine using 1-D simulation engine code (GT-Power)
in terms of Brake Specific Fuel Consumptions (BSFC) at various engine speeds and Brake Mean
Effective Pressures (BMEP). The model of a 6-cylinder turbocharged engine (Holset HDX55V) was
calibrated using an experimental BSFC map to predict engine exhaust thermodynamic conditions
such as exhaust mass flow rate and exhaust temperature under various operating conditions.
These engine exhaust conditions were then utilized to feed the inlet conditions for both the ORC
and turbocompounding models, evaluating the available exhaust energy to be recovered by each
technology. Firstly the ORC system model was simulated to obtain the power that can be generated
from the system. Having this additional power converted to useful work, the BSFC was observed
to reduce around 2–5% depending upon engine’s speed and BMEP. The initial model of the engine
was then modified by considering a second turbine representing turbocompounding heat recovery
system. The BSFC was increased due to the back-pressure from the second turbine, but the energy
generated from the turbine was sufficient to reduce the BSFC further. However, by application of
turbocompounding no improvement in BSFC was achieved at low engine’s speeds. It is concluded
that ORC heat recovery system produces a satisfactory results at low engine speeds with both low
and high loads whereas at medium and high engine speeds turbocompounding heat recovery system
causes higher BSFC reduction
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Design of the Organic Rankine Cycle for High-Efficiency Diesel Engines in Marine Applications
Data Availability Statement:
Data available on request due to privacyCopyright © 2023 by the authors. Over the past few years, fuel prices have increased dramatically, and emissions regulations have become stricter in maritime applications. In order to take these factors into consideration, improvements in fuel consumption have become a mandatory factor and a main task of research and development departments in this area. Internal combustion engines (ICEs) can exploit only about 15–40% of chemical energy to produce work effectively, while most of the fuel energy is wasted through exhaust gases and coolant. Although there is a significant amount of wasted energy in thermal processes, the quality of that energy is low owing to its low temperature and provides limited potential for power generation consequently. Waste heat recovery (WHR) systems take advantage of the available waste heat for producing power by utilizing heat energy lost to the surroundings at no additional fuel costs. Among all available waste heat sources in the engine, exhaust gas is the most potent candidate for WHR due to its high level of exergy. Regarding WHR technologies, the well-known Rankine cycles are considered the most promising candidate for improving ICE thermal efficiency. This study is carried out for a six-cylinder marine diesel engine model operating with a WHR organic Rankine cycle (ORC) model that utilizes engine exhaust energy as input. Using expander inlet conditions in the ORC model, preliminary turbine design characteristics are calculated. For this mean-line model, a MATLAB code has been developed. In off-design expander analysis, performance maps are created for different speed and pressure ratios. Results are produced by integrating the polynomial correlations between all of these parameters into the ORC model. ORC efficiency varies in design and off-design conditions which are due to changes in expander input conditions and, consequently, net power output. In this study, ORC efficiency varies from a minimum of 6% to a maximum of 12.7%. ORC efficiency performance is also affected by certain variables such as the coolant flow rate, heat exchanger’s performance etc. It is calculated that with the increase of coolant flow rate, ORC efficiency increases due to the higher turbine work output that is made possible, and the condensing pressure decreases. It is calculated that ORC can improve engine Brake Specific Fuel Consumption (BSFC) from a minimum of 2.9% to a maximum of 5.1%, corresponding to different engine operating points. Thus, decreasing overall fuel consumption shows a positive effect on engine performance. It can also increase engine power output by up to 5.42% if so required for applications where this may be deemed necessary and where an appropriate mechanical connection is made between the engine shaft and the expander shaft. The ORC analysis uses a bespoke expander design methodology and couples it to an ORC design architecture method to provide an important methodology for high-efficiency marine diesel engine systems that can extend well beyond the marine sector and into the broader ORC WHR field and are applicable to many industries (as detailed in the Introduction section of this paper).This research received no external funding
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Electric Vehicle Modelling for Future Technology and Market Penetration Analysis
Data Availability Statement: The original contributions presented in the study are included in the article/Supplementary Material, further inquiries can be directed to the corresponding author.The transportation sector is generally thought to be contributing up to 25% of all greenhouse gases (GHG) emissions globally. Hence, reducing the usage of fossil fuels by the introduction of electrified powertrain technologies such as hybrid electric vehicle (HEV), battery electric vehicle (BEV) and Fuel Cell Electric Vehicle (FCEV) is perceived as a way towards a more sustainable future. With a seemingly more significant shift towards BEV development and roll-out, the research and development of BEV technologies has taken on increasing importance in improving BEV performance and ensuring its competitiveness. Numerical simulation, using MATLAB, is performed as a tool to investigate and to improve the overall performance of BEVs. This study provides an overview of the possible technology outcome and market consequences for future compact BEVs along with HEVs, FCEVs and internal combustion engine vehicles (ICEV). The techno-economics of BEVs, market projection and cost analysis up to 2050 are investigated, as are important BEV characteristics alongside those of other types of vehicles. Well-to-wheel analysis of BEVs is also studied and compared with HEV, FCEV and ICE
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Comparative Assessment of sCO2 Cycles, Optimal ORC, and Thermoelectric Generators for Exhaust Waste Heat Recovery Applications from Heavy-Duty Diesel Engines
Data Availability Statement: Data available on request due to privacy.Copyright © 2023 by the authors. This study aimed to investigate the potential of supercritical carbon dioxide (sCO2), organic Rankine cycle (ORC), and thermoelectric generator (TEG) systems for application in automotive exhaust waste heat recovery (WHR) applications. More specifically, this paper focuses on heavy-duty diesel engines applications such as marine, trucks, and locomotives. The results of the simulations show that sCO2 systems are capable of recovering the highest amount of power from exhaust gases, followed by ORC systems. The sCO2 system recovered 19.5 kW at the point of maximum brake power and 10.1 kW at the point of maximum torque. Similarly, the ORC system recovered 14.7 kW at the point of maximum brake power and 7.9 kW at the point of maximum torque. Furthermore, at a point of low power and torque, the sCO2 system recovered 4.2 kW of power and the ORC system recovered 3.3 kW. The TEG system produced significantly less power (533 W at maximum brake power, 126 W at maximum torque, and 7 W at low power and torque) at all three points of interest due to the low system efficiency in comparison to sCO2 and ORC systems. From the results, it can be concluded that sCO2 and ORC systems have the biggest potential impact in exhaust WHR applications provided the availability of heat and that their level of complexity does not become prohibitive.This research received no external funding
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Numerical Study on Hydrogen–Gasoline Dual-Fuel Spark Ignition Engine
Data Availability Statement:
This study did not report any data.Copyright © 2022 by the authors. Hydrogen, as a suitable and clean energy carrier, has been long considered a primary fuel or in combination with other conventional fuels such as gasoline and diesel. Since the density of hydrogen is very low, in port fuel-injection configuration, the engine’s volumetric efficiency reduces due to the replacement of hydrogen by intake air. Therefore, hydrogen direct in-cylinder injection (injection after the intake valve closes) can be a suitable solution for hydrogen utilization in spark ignition (SI) engines. In this study, the effects of hydrogen direct injection with different hydrogen energy shares (HES) on the performance and emissions characteristics of a gasoline port-injection SI engine are investigated based on reactive computational fluid dynamics. Three different injection timings of hydrogen together with five different HES are applied at low and full load on a hydrogen–gasoline dual-fuel SI engine. The results show that retarded hydrogen injection timing increases the concentration of hydrogen near the spark plug, resulting in areas with higher average temperatures, which led to NOX emission deterioration at −120 Crank angle degree After Top Dead Center (CAD aTDC) start of injection (SOI) compared to the other modes. At −120 CAD aTDC SOI for 50% HES, the amount of NOX was 26% higher than −140 CAD aTDC SOI. In the meanwhile, an advanced hydrogen injection timing formed a homogeneous mixture of hydrogen, which decreased the HC and soot concentration, so that −140 CAD aTDC SOI implied the lowest amount of HC and soot. Moreover, with the increase in the amount of HES, the concentrations of CO, CO2 and soot were reduced. Having the HES by 50% at −140 CAD aTDC SOI, the concentrations of particulate matter (PM), CO and CO2 were reduced by 96.3%, 90% and 46%, respectively. However, due to more complete combustion and an elevated combustion average temperature, the amount of NOX emission increased drastically.This research received no external funding
Variable Geometry Turbocharger Technologies for Exhaust Energy Recovery and Boosting-A Review
As emissions regulations become increasingly demanding, higher power density engine (downsized/downspeeded and increasingly right-sized) requirements are driving the development of turbocharging systems. Variable geometry turbocharging (VGT) at its most basic level is the first step up from standard fixed geometry turbocharger systems. Currently, VGTs offer significant alternative options or complementarity vis-Ã -vis more advanced turbocharging options. This review details the range of prominent variable geometry technologies that are commercially available or openly under development, for both turbines and compressors and discusses the relative merits of each. Along with prominent diesel-engine boosting systems, attention is given to the control schemes employed and the actuation systems required to operate variable geometry devices, and the specific challenges associated with turbines designed for gasoline engines
Study on pollutants formation under knocking combustion conditions using an optical single cylinder SI research engine
The aim of this experimental study is to investigate the pollutants formation and cyclic emission variability under knocking combustion conditions. A great number of studies extensively describe the phenomenon of knock and its combustion characteristics as well as the effect of knock on engine performance; however the impact of knocking combustion on pollutants formation and how it affects cyclic emission variability has not been previously explored. In this study, an optical single cylinder SI research engine and fast response analyzers were employed to experimentally correlate knocking combustion characteristics with cyclic resolved emissions from cycle to cycle. High-speed natural light photography imaging and simultaneous in-cylinder pressure measurements were obtained from the optical research engine to interpret emissions formation under knocking combustion. The test protocol included the investigation of the effect of various engine parameters such as ignition timing and mixture air/fuel ratio on knocking combustion and pollutant formation. Results showed that at stoichiometric conditions by advancing spark timing from MBT to knock intensity equal to 6 bar, instantaneous NO and HC emissions are increased by up to 60% compared to the MBT operating conditions. A further increase of knock intensity at the limits of pre-ignition region was found to significantly drop NO emissions. Conversely, it was found that when knocking combustion occurs at lean conditions, NO emissions are enhanced as knock intensity is increased
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