Experimental investigation of in-cylinder air flow to optimize number of helical guide vanes to enhance DI diesel engine performance using mamey sapote biodiesel

Science.gov (United States)

Kumar, A. Raj; Janardhana Raju, G.; Hemachandra Reddy, K.

2018-03-01

The current research work investigates the influence of helical guide vanes in to the intake runner of a D.I diesel engine operating by the high viscous Mamey Sapote biodiesel to enhance in-cylinder suction air flow features. Helical guide vanes of different number of vanes are produced from 3D printing and placed in the intake manifold to examine the air flow characteristics. Four different helical guide vane devices namely 3, 4, 5 and 6 vanes of the same dimensions are tested in a D.I diesel engine operating with Mamey Sapote biodiesel blend. As per the experimental results of engine performance and emission characteristics, it is found that 5 vanes helical guide vane swirl device exhibited in addition number of increased improvements such as the brake power and bake thermal efficiency by 2.4% and 8.63% respectively and the HC, NOx, Carbon monoxide and, Smoke densities are reduced by 15.62%, 4.23%, 14.27% and 9.6% at peak load operating conditions as collate with normal engine at the same load. Hence this investigation concluded that Helical Guide Vane Devices successfully enhanced the in-cylinder air flow to improve better addition of Mamey Sapote biodiesel with air leading in better performance of the engine than without vanes.

Perturbing engine performance measurements to determine optimal engine control settings

Science.gov (United States)

Jiang, Li; Lee, Donghoon; Yilmaz, Hakan; Stefanopoulou, Anna

2014-12-30

Methods and systems for optimizing a performance of a vehicle engine are provided. The method includes determining an initial value for a first engine control parameter based on one or more detected operating conditions of the vehicle engine, determining a value of an engine performance variable, and artificially perturbing the determined value of the engine performance variable. The initial value for the first engine control parameter is then adjusted based on the perturbed engine performance variable causing the engine performance variable to approach a target engine performance variable. Operation of the vehicle engine is controlled based on the adjusted initial value for the first engine control parameter. These acts are repeated until the engine performance variable approaches the target engine performance variable.

Performance Enhancement of One and Two-Shaft Industrial Turboshaft Engines Topped With Wave Rotors

Science.gov (United States)

Fatsis, Antonios

2018-05-01

Wave rotors are rotating equipment designed to exchange energy between high and low enthalpy fluids by means of unsteady pressure waves. In turbomachinery, they can be used as topping devices to gas turbines aiming to improve performance. The integration of a wave rotor into a ground power unit is far more attractive than into an aeronautical application, since it is not accompanied by any inconvenience concerning the over-weight and extra dimensioning. Two are the most common types of ground industrial gas turbines: The one-shaft and the two-shaft engines. Cycle analysis for both types of gas turbine engines topped with a four-port wave rotor is calculated and their performance is compared to the performance of the baseline engine accordingly. It is concluded that important benefits are obtained in terms of specific work and specific fuel consumption, especially compared to baseline engines with low compressor pressure ratio and low turbine inlet temperature.

An Educational Program for Newcomers to Enhance their Engineering Motivation and Creativity in Faculty of Engineering at Shizuoka University

Science.gov (United States)

Azuma, Naoto; Fujima, Nobuhisa; Nakamura, Tamotsu; Yamada, Shinkichi; Makizawa, Hisamitsu; Nakamura, Takato

In Faculty of Engineering at Shizuoka University, a new one-year educational program of mechatronics for newcomers will start at April in 2006. This program involves three stages designed to enhance their motivation and creativity in engineering. At the first and second stages, there are three activities; practicing digital circuits, controlling robots with Boe-Bot from Parallax Inc., and making their own microcontroller boards. At the third stage, each student cooperates with his team-mates to make a robot loaded his own board and through the game-type of competition the performance of each team-robot is scored. Through this program, we hope that our students enhance their engineering motivation and creativity.

Enhanced Emission Performance and Fuel Efficiency for HD Methane Engines. Literature Study. Final Report

Energy Technology Data Exchange (ETDEWEB)

Broman, R.; Staalhammar, P.; Erlandsson, L.

2010-05-15

A literature survey has been conducted in order to define state-of-the-art for methane fuelled engines to be used in heavy duty vehicles. Use of methane can be favourable to increase security of supply and mitigate CO2 emissions, especially when the methane origins from biomass. Furthermore, methane used as a fuel in heavy duty engines has a potential to reduce toxic exhaust emissions. Historically, use of methane in heavy duty engines has often been hampered by poor efficiency, i.e. high fuel consumption when using the Otto-cycle. However, current generation technology engines might be within 5-10 % of the efficiency of Diesel engine technology. In this context it is worth mentioning that compliance-driven changes for meeting future emission regulations for Diesel engines may have a negative impact on fuel efficiency, thereby narrowing the gap. This may present an opportunity for heavy methane fuelled engines. The reliability and durability of the exhaust aftertreatment devices for methane fuelled engines has also given rise to some concerns. Some concepts are performing acceptable while others do not meet expectations. This is partly due to difficulties in handling methane in the aftertreatment device and partly to issues in the design of the ignition system. Methane is a fuel used worldwide and has a potential to be an important complement to Diesel oil. There are two categories of HD methane engines available to end-users: Retrofitted engines, which often include computer controlled retrofit systems developed as 'bolt-on' technologies that can be removed if necessary, to resell the vehicle with a normal diesel engine, and those developed specifically for and in conjunction with engine manufacturers and delivered to customers as factory-built engines or vehicles (OEM). Additionally, both these categories can include engines that use the Otto- or Diesel combustion cycles. When adapting a HD Diesel engine to run on methane there are two options, either

Enhancement of keratinocyte performance in the production of tissue-engineered skin using a low-calcium medium.

Science.gov (United States)

Hernon, Catherine A; Harrison, Caroline A; Thornton, Daniel J A; MacNeil, Sheila

2007-01-01

The success of laboratory-expanded autologous keratinocytes for the treatment of severe burn injuries is often compromised by their lack of dermal remnants and failure to establish a secure dermo-epidermal junction on the wound bed. We have developed a tissue-engineered skin substitute for in vivo use, based on a sterilized donor human dermis seeded with autologous keratinocytes and fibroblasts. However, culture rates are currently too slow for clinical use in acute burns. Our aim in this study was to increase the rate of production of tissue-engineered skin. Two approaches were explored: one using a commercial low-calcium media and the other supplementing well-established media for keratinocyte culture with the calcium-chelating agent ethylene glutamine tetra-acetic acid (EGTA). Using commercial low-calcium media for both the initial cell culture and subsequent culture of tissue-engineered skin did not produce tissue suitable for clinical use. However, it was possible to enhance the initial proliferation of keratinocytes and to increase their horizontal migration in tissue-engineered skin by supplementing established culture medium with 0.04 mM EGTA without sacrificing epidermal attachment and differentiation. Enhancement of keratinocyte migration with EGTA was also maximal in the absence of fibroblasts or basement membrane.

Gender and engineering aptitude: Is the color of science, technology, engineering, and math materials related to children's performance?

Science.gov (United States)

Mulvey, Kelly Lynn; Miller, Bridget; Rizzardi, Victoria

2017-08-01

To investigate gender stereotypes, demonstrated engineering aptitude, and attitudes, children (N=105) solved an engineering problem using either pastel-colored or primary-colored materials. Participants also evaluated the acceptability of denial of access to engineering materials based on gender and counter-stereotypic preferences (i.e., a boy who prefers pastel-colored materials). Whereas material color was not related to differences in female participants' performance, younger boys assigned to pastel materials demonstrated lower engineering aptitude than did other participants. In addition, results documented age- and gender-related differences; younger participants, and sometimes boys, exhibited less flexibility regarding gender stereotypes than did older and female participants. The findings suggest that attempts to enhance STEM (science, technology, engineering, and math) engagement or performance through the color of STEM materials may have unintended consequences. Copyright © 2017 Elsevier Inc. All rights reserved.

Engineering performance metrics

Science.gov (United States)

Delozier, R.; Snyder, N.

1993-03-01

Implementation of a Total Quality Management (TQM) approach to engineering work required the development of a system of metrics which would serve as a meaningful management tool for evaluating effectiveness in accomplishing project objectives and in achieving improved customer satisfaction. A team effort was chartered with the goal of developing a system of engineering performance metrics which would measure customer satisfaction, quality, cost effectiveness, and timeliness. The approach to developing this system involved normal systems design phases including, conceptual design, detailed design, implementation, and integration. The lessons teamed from this effort will be explored in this paper. These lessons learned may provide a starting point for other large engineering organizations seeking to institute a performance measurement system accomplishing project objectives and in achieving improved customer satisfaction. To facilitate this effort, a team was chartered to assist in the development of the metrics system. This team, consisting of customers and Engineering staff members, was utilized to ensure that the needs and views of the customers were considered in the development of performance measurements. The development of a system of metrics is no different than the development of any type of system. It includes the steps of defining performance measurement requirements, measurement process conceptual design, performance measurement and reporting system detailed design, and system implementation and integration.

Enhancement of Engine Oil Wear and Friction Control Performance Through Titanium Additive Chemistry

International Nuclear Information System (INIS)

Guevremont, J.; Guinther, G.; Szemenyei, D.; Devlin, M.; Jao, T.; Jaye, C.; Woicik, J.; Fischer, D.

2008-01-01

Traditionally, wear protection and friction modification by engine oil is provided by zinc dithiophosphate (ZDDP) or other phosphorus compounds. These additives provide effective wear protection and friction control on engine parts through formation of a glassy polyphosphate antiwear film. However, the deposition of phosphorus species on automotive catalytic converters from lubricants has been known for some time to have a detrimental effect of poisoning the catalysts. To mitigate the situation, the industry has been making every effort to find ZDDP-replacement additives that are friendly to catalysts. Toward this goal we have investigated a titanium additive chemistry as a ZDDP replacement. Fully formulated engine oils incorporating this additive component have been found to be effective in reducing wear and controlling friction in a high-frequency reciprocating rig (HFRR), 4-ball bench wear, Sequence IIIG, and Sequence IVA engine tests. Surface analysis of the tested parts by Auger electron spectroscopy, secondary ion mass spectrometry (SIMS), and X-ray photoelectron spectroscopy (XPS) have shown that Ti species have been incorporated into the wear tracks and can only be found on the wear tracks. We used synchrotron based near edge X-ray absorption fine structure (NEXAFS) to investigate the chemical bonding mechanism of the Ti additive with the metal surface that affects the wear improvement mechanism. We postulate that Ti provides antiwear enhancement through inclusion in the metal/metal oxide structure of the ferrous surface by forming FeTiO3.

Covariance of engineering management characteristics with engineering employee performance

Science.gov (United States)

Hesketh, Andrew Arthur

1998-12-01

As business in the 1990's grapples with the impact of continuous improvement and quality to meet market demands, there is an increased need to improve the leadership capabilities of our managers. Engineers have indicated desire for certain managerial characteristics in their leadership but there have been no studies completed that approached the problem of determining what managerial characteristics were best at improving employee performance. This study addressed the idea of identifying certain managerial characteristics that enhance employee performance. In the early 1990's, McDonnell Douglas Aerospace in St. Louis used a forced distribution system and allocated 35% of its employees into a "exceeds expectations" category and 60% into a "meets expectations" category. A twenty-question 5 point Likert scale survey on managerial capabilities was administered to a sample engineering population that also obtained their "expectations" category. A single factor ANOVA on the survey results determined a statistical difference between the "exceeds" and "meets" employees with four of the managerial capability questions. The "exceeds expectations" employee indicated that supervision did a better job of supporting subordinate development, clearly communicating performance expectations, and providing timely performance feedback when compared to the "meets expectations" employee. The "meets expectations" employee felt that their opinions, when different from their supervisor's, were more often ignored when compared to the "exceeds expectations" employee. These four questions relate to two specific managerial characteristics, "gaining (informal) authority and support" or "control" characteristic and "providing assistance and guidance" or "command" characteristic, that can be emphasized in managerial training programs.

The Effect of Modified Control Limits on the Performance of a Generic Commercial Aircraft Engine

Science.gov (United States)

Csank, Jeffrey T.; May, Ryan D.; Gou, Ten-Huei; Litt, Jonathan S.

2012-01-01

This paper studies the effect of modifying the control limits of an aircraft engine to obtain additional performance. In an emergency situation, the ability to operate an engine above its normal operating limits and thereby gain additional performance may aid in the recovery of a distressed aircraft. However, the modification of an engine s limits is complex due to the risk of an engine failure. This paper focuses on the tradeoff between enhanced performance and risk of either incurring a mechanical engine failure or compromising engine operability. The ultimate goal is to increase the engine performance, without a large increase in risk of an engine failure, in order to increase the probability of recovering the distressed aircraft. The control limit modifications proposed are to extend the rotor speeds, temperatures, and pressures to allow more thrust to be produced by the engine, or to increase the rotor accelerations and allow the engine to follow a fast transient. These modifications do result in increased performance; however this study indicates that these modifications also lead to an increased risk of engine failure.

Towards artificial intelligence based diesel engine performance control under varying operating conditions using support vector regression

Directory of Open Access Journals (Sweden)

Naradasu Kumar Ravi

2013-01-01

Full Text Available Diesel engine designers are constantly on the look-out for performance enhancement through efficient control of operating parameters. In this paper, the concept of an intelligent engine control system is proposed that seeks to ensure optimized performance under varying operating conditions. The concept is based on arriving at the optimum engine operating parameters to ensure the desired output in terms of efficiency. In addition, a Support Vector Machines based prediction model has been developed to predict the engine performance under varying operating conditions. Experiments were carried out at varying loads, compression ratios and amounts of exhaust gas recirculation using a variable compression ratio diesel engine for data acquisition. It was observed that the SVM model was able to predict the engine performance accurately.

Role of fin material and nanofluid in performance enhancement of automobile radiator

Science.gov (United States)

Jadar, Raju; Shashishekar, K. S.; Channa Keshava Naik, N.

2018-04-01

An effective cooling system can avoid engine and its components from overheating and helps in achieving optimum engine performance. This work deals with the fabrication and performance evaluation of an automobile radiator with i) Aluminum fins and ii) Al-MWCNT fins using 0.1 w/v% f-MWCNT nanofluid. F-MWCNT nanoparticles in the base fluid improves the rate of heat transfer in an automobile radiator integrated with Al-MWCNT fins. The enhancement of heat transfer mainly depends on the quantity of F-MWCNT nanoparticles added to the host fluid. During the study it was found that at a low weight by volume concentration of nanofluid the heat transfer enhancement of 8% was achieved using Al-MWCNT fins compared to base fluid.

Performance optimum analysis of an irreversible molten carbonate fuel cell–Stirling heat engine hybrid system

International Nuclear Information System (INIS)

Chen, Liwei; Zhang, Houcheng; Gao, Songhua; Yan, Huixian

2014-01-01

A new hybrid system mainly consists of a molten carbonate fuel cell (MCFC) and a Stirling heat engine is established, where the Stirling heat engine is driven by the high-quality waste heat generated in the MCFC. Based on the electrochemistry and non-equilibrium thermodynamics, analytical expressions for the efficiency and power output of the hybrid system are derived by taking various irreversible losses into account. It shows that the performance of the MCFC can be greatly enhanced by coupling a Stirling heat engine to further convert the waste heat for power generation. By employing numerical calculations, not only the influences of multiple irreversible losses on the performance of the hybrid system are analyzed, but also the impacts of some operating conditions such as the operating temperature, input gas compositions and operating pressure on the performance of the hybrid system are also discussed. The investigation method in the present paper is feasible for some other similar energy conversion systems as well. - Highlights: • A model of MCFC–Stirling heat engine hybrid system is established. • Analytical expressions for the efficiency and power output are derived. • MCFC performance can be greatly enhanced by coupling a Stirling heat engine. • Effects of some operating conditions on the performance are discussed. • Optimum operation regions are subdivided by multi-objective optimization method

Fabrication and characterization of electrospun poly-L-lactide/gelatin graded tubular scaffolds: Toward a new design for performance enhancement in vascular tissue engineering

Directory of Open Access Journals (Sweden)

A. Yazdanpanah

2015-10-01

Full Text Available In this study, a new design of graded tubular scaffolds have been developed for the performance enhancement in vascular tissue engineering. The graded poly-L-lactide (PLLA and gelatin fibrous scaffolds produced by electrospining were then characterized. The morphology, degradability, porosity, pore size and mechanical properties of four tubular scaffolds (graded PLLA/gelatin, layered PLLA/gelatin, PLLA and gelatin scaffolds have been investigated. The tensile tests demonstrated that the mechanical strength and also the estimated burst pressure of the graded scaffolds were significantly increased in comparison with the layered and gelatin scaffolds. This new design, resulting in an increase in the mechanical properties, suggested the widespread use of these scaffolds in vascular tissue engineering in order to prepare more strengthened vessels.

Interface Engineering of Organic Schottky Barrier Solar Cells and Its Application in Enhancing Performances of Planar Heterojunction Solar Cells

Science.gov (United States)

Jin, Fangming; Su, Zisheng; Chu, Bei; Cheng, Pengfei; Wang, Junbo; Zhao, Haifeng; Gao, Yuan; Yan, Xingwu; Li, Wenlian

2016-05-01

In this work, we describe the performance of organic Schottky barrier solar cells with the structure of ITO/molybdenum oxide (MoOx)/boron subphthalocyanine chloride (SubPc)/bathophenanthroline (BPhen)/Al. The SubPc-based Schottky barrier solar cells exhibited a short-circuit current density (Jsc) of 2.59 mA/cm2, an open-circuit voltage (Voc) of 1.06 V, and a power conversion efficiency (PCE) of 0.82% under simulated AM1.5 G solar illumination at 100 mW/cm2. Device performance was substantially enhanced by simply inserting thin organic hole transport material into the interface of MoOx and SubPc. The optimized devices realized a 180% increase in PCE of 2.30% and a peak Voc as high as 1.45 V was observed. We found that the improvement is due to the exciton and electron blocking effect of the interlayer and its thickness plays a vital role in balancing charge separation and suppressing quenching effect. Moreover, applying such interface engineering into MoOx/SubPc/C60 based planar heterojunction cells substantially enhanced the PCE of the device by 44%, from 3.48% to 5.03%. Finally, we also investigated the requirements of the interface material for Schottky barrier modification.

Enhancing learning in geosciences and water engineering via lab activities

Science.gov (United States)

Valyrakis, Manousos; Cheng, Ming

2016-04-01

This study focuses on the utilisation of lab based activities to enhance the learning experience of engineering students studying Water Engineering and Geosciences. In particular, the use of modern highly visual and tangible presentation techniques within an appropriate laboratory based space are used to introduce undergraduate students to advanced engineering concepts. A specific lab activity, namely "Flood-City", is presented as a case study to enhance the active engagement rate, improve the learning experience of the students and better achieve the intended learning objectives of the course within a broad context of the engineering and geosciences curriculum. Such activities, have been used over the last few years from the Water Engineering group @ Glasgow, with success for outreach purposes (e.g. Glasgow Science Festival and demos at the Glasgow Science Centre and Kelvingrove museum). The activity involves a specific setup of the demonstration flume in a sand-box configuration, with elements and activities designed so as to gamely the overall learning activity. Social media platforms can also be used effectively to the same goals, particularly in cases were the students already engage in these online media. To assess the effectiveness of this activity a purpose designed questionnaire is offered to the students. Specifically, the questionnaire covers several aspects that may affect student learning, performance and satisfaction, such as students' motivation, factors to effective learning (also assessed by follow-up quizzes), and methods of communication and assessment. The results, analysed to assess the effectiveness of the learning activity as the students perceive it, offer a promising potential for the use of such activities in outreach and learning.

Using Technology-Enhanced, Cooperative, Group-Project Learning for Student Comprehension and Academic Performance

Science.gov (United States)

Tlhoaele, Malefyane; Suhre, Cor; Hofman, Adriaan

2016-01-01

Cooperative learning may improve students' motivation, understanding of course concepts, and academic performance. This study therefore enhanced a cooperative, group-project learning technique with technology resources to determine whether doing so improved students' deep learning and performance. A sample of 118 engineering students, randomly…

Nonlinearities in reservoir engineering: Enhancing quantum correlations

Science.gov (United States)

Hu, Xiangming; Hu, Qingping; Li, Lingchao; Huang, Chen; Rao, Shi

2017-12-01

There are two decisive factors for quantum correlations in reservoir engineering, but they are strongly reversely dependent on the atom-field nonlinearities. One is the squeezing parameter for the Bogoliubov modes-mediated collective interactions, while the other is the dissipative rates for the engineered collective dissipations. Exemplifying two-level atomic ensembles, we show that the moderate nonlinearities can compromise these two factors and thus enhance remarkably two-mode squeezing and entanglement of different spin atomic ensembles or different optical fields. This suggests that the moderate nonlinearities of the two-level systems are more advantageous for applications in quantum networks associated with reservoir engineering.

Comparative proteomics analysis of engineered Saccharomyces cerevisiae with enhanced biofuel precursor production.

Directory of Open Access Journals (Sweden)

Xiaoling Tang

Full Text Available The yeast Saccharomyces cerevisiae was metabolically modified for enhanced biofuel precursor production by knocking out genes encoding mitochondrial isocitrate dehydrogenase and over-expression of a heterologous ATP-citrate lyase. A comparative iTRAQ-coupled 2D LC-MS/MS analysis was performed to obtain a global overview of ubiquitous protein expression changes in S. cerevisiae engineered strains. More than 300 proteins were identified. Among these proteins, 37 were found differentially expressed in engineered strains and they were classified into specific categories based on their enzyme functions. Most of the proteins involved in glycolytic and pyruvate branch-point pathways were found to be up-regulated and the proteins involved in respiration and glyoxylate pathway were however found to be down-regulated in engineered strains. Moreover, the metabolic modification of S. cerevisiae cells resulted in a number of up-regulated proteins involved in stress response and differentially expressed proteins involved in amino acid metabolism and protein biosynthesis pathways. These LC-MS/MS based proteomics analysis results not only offered extensive information in identifying potential protein-protein interactions, signal pathways and ubiquitous cellular changes elicited by the engineered pathways, but also provided a meaningful biological information platform serving further modification of yeast cells for enhanced biofuel production.

Application of selected advanced technologies to high performance, single-engine, business airplanes

Science.gov (United States)

Domack, C. S.; Martin, G. L.

1984-01-01

Improvements in performance and fuel efficiency are evaluated for five new configurations of a six place, single turboprop, business airplane derived from a conventional, aluminum construction baseline aircraft. Results show the greatest performance gains for enhancements in natural laminar flow. A conceptual diesel engine provides greater fuel efficiency but reduced performance. Less significant effects are produced by the utilization of composite materials construction or by reconfiguration from tractor to pusher propeller installation.

Treatment of highway runoff : engineered filter media for pollutant removal through enhanced sorption : final report.

Science.gov (United States)

2015-07-27

The work performed in this study focused on the investigation of the use of engineered biofiltration layers to enhance the removal of roadway stormwater runoff contaminants (specifically nutrients, solids, heavy metals, and pH). Six Georgia native gr...

Engineering Students: Enhancing Employability Skills through PBL

Science.gov (United States)

H, Othman; Mat Daud K., A.; U, Ewon; Salleh B, Mohd; Omar N., H.; Baser J, Abd; Ismail M., E.; A, Sulaiman

2017-05-01

As a developing country, Malaysia faces challenging tasks to develop her economy just like many other countries. Nowadays, change involves many aspects like the economy from agriculture to manufacturing, technology from modern to more advanced ones; mindset from traditional to advanced and so on. Previous studies show that one of the major issues facing local graduates is the lack of employability skills. This problem concerns not only the government but undergraduates and institutions alike. From the pedagogical aspect, one of the more effective ways to improve this is through instructional delivery and in this case the use of Problem-based Learning (PBL). The need to adopt PBL should involved applied subjects undertaken by engineering students. Studies have shown that the use of PBL has been proven to make learning more attractive and effective. In this research, we studied the effectiveness of PBL towards enhancing employability skills among engineering undergraduates. This study adopted a combination of qualitative and quantitative approaches. Data was collected using documents analysis. Student samples comprised manufacturing engineering undergraduates from public institutions of higher learning in Malaysia. The results show that student’s employability skills can be enhanced using PBL. In addition, students become more competitive towards making them more relevance with the needs of the industry with regard to employability skills. In conclusion, PBL is a very effective catalyst towards raising the employability skills among engineering undergraduates and should be adopted in all engineering education.

Using technology-enhanced, cooperative, group-project learning for student comprehension and academic performance

Science.gov (United States)

Tlhoaele, Malefyane; Suhre, Cor; Hofman, Adriaan

2016-05-01

Cooperative learning may improve students' motivation, understanding of course concepts, and academic performance. This study therefore enhanced a cooperative, group-project learning technique with technology resources to determine whether doing so improved students' deep learning and performance. A sample of 118 engineering students, randomly divided into two groups, participated in this study and provided data through questionnaires issued before and after the experiment. The results, obtained through analyses of variance and structural equation modelling, reveal that technology-enhanced, cooperative, group-project learning improves students' comprehension and academic performance.

Enhanced Microgrid Dynamic Performance Using a Modulated Power Filter Based on Enhanced Bacterial Foraging Optimization

Directory of Open Access Journals (Sweden)

Ahmed M. Othman

2017-06-01

Full Text Available This paper presents a design of microgrid (MG with enhanced dynamic performance. Distributed energy resources (DER are widely used in MGs to match the various load types and profiles. DERs include solar PV cells, wind energy sources, fuel cells, batteries, micro gas-engines and storage elements. MG will include AC/DC circuits, developed power electronics devices, inverters and power electronic controllers. A novel modulated power filters (MPF device will be applied in MG design. Enhanced bacterial foraging optimization (EBFO will be proposed to optimize and set the MPF parameters to enhance and tune the MG dynamic response. Recent dynamic control is applied to minimize the harmonic reference content. EBFO will adapt the gains of MPF dynamic control. The present research achieves an enhancement of MG dynamic performance, in addition to ensuring improvements in the power factor, bus voltage profile and power quality. MG operation will be evaluated by the dynamic response to be fine-tuned by MPF based on EBFO. Digital simulations have validated the results to show the effectiveness and efficient improvement by the proposed strategy.

Enhancing the DEMO divertor target by interlayer engineering

Energy Technology Data Exchange (ETDEWEB)

Barrett, T.R., E-mail: tom.barrett@ccfe.ac.uk [CCFE, Culham Science Centre, Oxfordshire OX14 3DB (United Kingdom); McIntosh, S.C.; Fursdon, M.; Hancock, D.; Timmis, W.; Coleman, M. [CCFE, Culham Science Centre, Oxfordshire OX14 3DB (United Kingdom); Rieth, M.; Reiser, J. [Karlsruhe Institute for Technology, IMF-I, D-7602 Karlsruhe (Germany)

2015-10-15

Highlights: • The European ‘near-term’ DEMO forsees a water-cooled divertor. • Divertor targets typically use an interlayer between the armour and structure. • Engineering the properties of the interlayer can yield large gains in performance. • A response surface based design search and optimisation method is used. • A new design passes linear-elastic code rules up to applied heat flux of 18 MW/m{sup 2}. - Abstract: A robust water-cooled divertor target plate solution for DEMO has to date remained elusive. Common to all contemporary concepts is an interlayer at the boundary between the tungsten armour and the cooling structure. In this paper we show by design optimisation that an effectively designed interlayer can produce dramatic gains in power handling. By engineering the interlayer as part of the design study, it is found that divertor performance is enhanced by either a low conductivity ‘Thermal Break’ interlayer or an ‘Ultra-Compliant’ interlayer. For a 10 MW/m{sup 2} surface heat flux we find that a thermal conductivity of 15 W/mK and elastic modulus of 1 GPa are effective. A design is proposed which passes linear-elastic code rules up to an applied heat flux of 18 MW/m{sup 2}.

Enhancing the DEMO divertor target by interlayer engineering

International Nuclear Information System (INIS)

Barrett, T.R.; McIntosh, S.C.; Fursdon, M.; Hancock, D.; Timmis, W.; Coleman, M.; Rieth, M.; Reiser, J.

2015-01-01

Highlights: • The European ‘near-term’ DEMO forsees a water-cooled divertor. • Divertor targets typically use an interlayer between the armour and structure. • Engineering the properties of the interlayer can yield large gains in performance. • A response surface based design search and optimisation method is used. • A new design passes linear-elastic code rules up to applied heat flux of 18 MW/m"2. - Abstract: A robust water-cooled divertor target plate solution for DEMO has to date remained elusive. Common to all contemporary concepts is an interlayer at the boundary between the tungsten armour and the cooling structure. In this paper we show by design optimisation that an effectively designed interlayer can produce dramatic gains in power handling. By engineering the interlayer as part of the design study, it is found that divertor performance is enhanced by either a low conductivity ‘Thermal Break’ interlayer or an ‘Ultra-Compliant’ interlayer. For a 10 MW/m"2 surface heat flux we find that a thermal conductivity of 15 W/mK and elastic modulus of 1 GPa are effective. A design is proposed which passes linear-elastic code rules up to an applied heat flux of 18 MW/m"2.

Pilot-in-the-Loop Evaluation of a Yaw Rate to Throttle Feedback Control with Enhanced Engine Response

Science.gov (United States)

Litt, Jonathan S.; Guo, Ten-Huei; Sowers, T. Shane; Chicatelli, Amy K.; Fulton, Christopher E.; May, Ryan D.; Owen, A. Karl

2012-01-01

This paper describes the implementation and evaluation of a yaw rate to throttle feedback system designed to replace a damaged rudder. It can act as a Dutch roll damper and as a means to facilitate pilot input for crosswind landings. Enhanced propulsion control modes were implemented to increase responsiveness and thrust level of the engine, which impact flight dynamics and performance. Piloted evaluations were performed to determine the capability of the engines to substitute for the rudder function under emergency conditions. The results showed that this type of implementation is beneficial, but the engines' capability to replace the rudder is limited.

Performance limits of plasmon-enhanced organic photovoltaics

Energy Technology Data Exchange (ETDEWEB)

Karatay, Durmus U.; Ginger, David S., E-mail: ginger@chem.washington.edu [Department of Physics, University of Washington, Seattle, Washington 98195 (United States); Department of Chemistry, University of Washington, Seattle, Washington 98195 (United States); Salvador, Michael [Department of Chemistry, University of Washington, Seattle, Washington 98195 (United States); Yao, Kai [Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195 (United States); Jen, Alex K.-Y. [Department of Chemistry, University of Washington, Seattle, Washington 98195 (United States); Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195 (United States)

2014-07-21

We use a combination of experiment and modeling to explore the promise and limitations of using plasmon-resonant metal nanoparticles to enhance the device performance of organic photovoltaics (OPVs). We focus on optical properties typical of the current generation of low-bandgap donor polymers blended with the fullerene (6,6)-phenyl C{sub 71}-butyric acid methyl ester (PC{sub 71}BM) and use the polymer poly(indacenodithiophene-co-phenanthro[9,10-b]quinoxaline) (PIDT-PhanQ) as our test case. We model the optical properties and performance of these devices both in the presence and absence of a variety of colloidal silver nanoparticles. We show that for these materials, device performance is sensitive to the relative z-position and the density of nanoparticles inside the active layer. Using conservative estimates of the internal quantum efficiency for the PIDT-PhanQ/PC{sub 71}BM blend, we calculate that optimally placed silver nanoparticles could yield an enhancement in short-circuit current density of over 31% when used with ∼ 80-nm-thick active layers, resulting in an absolute increase in power conversion efficiency of up to ∼2% for the device based on optical engineering.

Morphology engineering of ZnO nanostructures for high performance supercapacitors: enhanced electrochemistry of ZnO nanocones compared to ZnO nanowires

Science.gov (United States)

He, Xiaoli; Yoo, Joung Eun; Lee, Min Ho; Bae, Joonho

2017-06-01

In this work, the morphology of ZnO nanostructures is engineered to demonstrate enhanced supercapacitor characteristics of ZnO nanocones (NCs) compared to ZnO nanowires (NWs). ZnO NCs are obtained by chemically etching ZnO NWs. Electrochemical characteristics of ZnO NCs and NWs are extensively investigated to demonstrate morphology dependent capacitive performance of one dimensional ZnO nanostructures. Cyclic voltammetry measurements on these two kinds of electrodes in a three-electrode cell confirms that ZnO NCs exhibit a high specific capacitance of 378.5 F g-1 at a scan rate of 20 mV s-1, which is almost twice that of ZnO NWs (191.5 F g-1). The charge-discharge and electrochemical impedance spectroscopy measurements also clearly result in enhanced capacitive performance of NCs as evidenced by higher specific capacitances and lower internal resistance. Asymmetric supercapacitors are fabricated using activated carbon (AC) as the negative electrode and ZnO NWs and NCs as positive electrodes. The ZnO NC⫽AC can deliver a maximum specific capacitance of 126 F g-1 at a current density of 1.33 A g-1 with an energy density of 25.2 W h kg-1 at the power density of 896.44 W kg-1. In contrast, ZnO NW⫽AC displays 63% of the capacitance obtained from the ZnO NC⫽AC supercapacitor. The enhanced performance of NCs is attributed to the higher surface area of ZnO nanostructures after the morphology is altered from NWs to NCs.

Prechamber Compression-Ignition Engine Performance

Science.gov (United States)

Moore, Charles S; Collins, John H , Jr

1938-01-01

Single-cylinder compression-ignition engine tests were made to investigate the performance characteristics of prechamber type of cylinder head. Certain fundamental variables influencing engine performance -- clearance distribution, size, shape, and direction of the passage connecting the cylinder and prechamber, shape of prechamber, cylinder clearance, compression ratio, and boosting -- were independently tested. Results of motoring and of power tests, including several typical indicator cards, are presented.

Improving engineering performance by utilizing process indicators

International Nuclear Information System (INIS)

Roberts, T.E.

1992-01-01

The purpose of the work discussed in this paper was to develop engineering performance indicators used to facilitate improvement to the technical quality, cost-effectiveness, and delivery of engineering products and service. This work was specifically tailored for engineering support products and service associated with operating Florida Power and Light Company (FP and L) nuclear plants. The engineering process for the development of plant change packages was reviewed to identify critical in-process activities. Because each engineering project usually deals with a specific component or plant system, the different tasks are usually technically unique and of varying magnitudes. Although each engineering product may employ different analytical techniques or industry code requirements, several activities in documenting the engineering design process are generic. The quality of performance in these activities can be monitored analogously to the steps in a manufacturing process. This concept builds quality concepts into the package in lieu of inspecting package quality at the end of the process. The work has resulted in a valuable self-assessment tool that serves as a basis for engineering process improvements. The indicators are published in a semi-yearly performance report for FP and L contractors as well as FP and L in-house engineering work. Contracts have been set up to base fees on meeting targets established for the performance report. The ability to meet performance targets continues to improve

Performance Estimation and Fault Diagnosis Based on Levenberg–Marquardt Algorithm for a Turbofan Engine

Directory of Open Access Journals (Sweden)

Junjie Lu

2018-01-01

Full Text Available Establishing the schemes of accurate and computationally efficient performance estimation and fault diagnosis for turbofan engines has become a new research focus and challenges. It is able to increase reliability and stability of turbofan engine and reduce the life cycle costs. Accurate estimation of turbofan engine performance counts on thoroughly understanding the components’ performance, which is described by component characteristic maps and the fault of each component can be regarded as the change of characteristic maps. In this paper, a novel method based on a Levenberg–Marquardt (LM algorithm is proposed to enhance the fidelity of the performance estimation and the credibility of the fault diagnosis for the turbofan engine. The presented method utilizes the LM algorithm to figure out the operating point in the characteristic maps, preparing for performance estimation and fault diagnosis. The accuracy of the proposed method is evaluated for estimating performance parameters in the transient case with Rayleigh process noise and Gaussian measurement noise. The comparison among the extended Kalman filter (EKF method, the particle filter (PF method and the proposed method is implemented in the abrupt fault case and the gradual degeneration case and it has been shown that the proposed method has the capability to lead to more accurate result for performance estimation and fault diagnosis of turbofan engine than current popular EKF and PF diagnosis methods.

Influence of anti-corrosion additive on the performance, emission and engine component wear characteristics of an IDI diesel engine fueled with palm biodiesel

International Nuclear Information System (INIS)

Ashraful, A.M.; Masjuki, H.H.; Kalam, M.A.; Rashedul, H.K.; Sajjad, H.; Abedin, M.J.

2014-01-01

Highlights: • Maximum engine performance was obtained at 2000 rpm for all fuel blends. • IRGALUBE 349 additive is enhances diesel engine performance. • Reduction of CO and NOx considerably using anti-corrosion additive except HC. • Engine wear decreases with using blended fuels with anti-corrosion additive. - Abstract: This study evaluates the effect of anti-corrosion additives such as 8% and 16% (vol.%) palm olein oil (PO) with ordinary diesel (OD) fuel on engine operation, emission behavior, engine part wear, and lubrication characteristics. This experiment was conducted on 4-cylinder and 4-stroke IDI diesel engine at different engine speed ranging from 1200 to 2800 RPM with 30% throttle setting under full load condition. The properties of the palm olein oil blends meet the ASTM D6751 and EN 14214 standards. At 2000 rpm, the experimental results revealed that the POD8A (0.2% Additive + 8% PO + 92% OD) and POD16A (0.2% Additive + 16% PO + 84% OD) blended fuels produced 0.5% and 0.51% higher brake power as well as 1.45% and 1.25% higher torque than same blends without additive, respectively. In comparison with ODF, the brake specific fuel consumption (BSFC) was found 1.8% and 3.1% higher for POD8A and POD16A blends, respectively. Anti-corrosion additive is found more effectual in enhancing the engine performance as such additive helps in timely ignition for complete burn in the combustion chamber. The results from engine emission indicated that POD8A and POD16A blended fuel reduced CO emissions by 11% and 6.6% and NOx emission by 2.5% and 1.09%, respectively in compared with OD fuel. Although HC emissions for all blended fuel and OD fuel increased at higher engine speed, the average HC emissions of all blended fuel were not higher than OD fuel. The application of anti-corrosion additives in POD blends reduced ferrous (Fe) wear debris concentration (WBC) by 17.3%. The reductions in WBC were about 16.1%, 10.8%, and 19.3%, 17.6% for copper (Cu) and aluminum

Molecular Engineering for Enhanced Charge Transfer in Thin-Film Photoanode.

Science.gov (United States)

Kim, Jeong Soo; Kim, Byung-Man; Kim, Un-Young; Shin, HyeonOh; Nam, Jung Seung; Roh, Deok-Ho; Park, Jun-Hyeok; Kwon, Tae-Hyuk

2017-10-11

We developed three types of dithieno[3,2-b;2',3'-d]thiophene (DTT)-based organic sensitizers for high-performance thin photoactive TiO 2 films and investigated the simple but powerful molecular engineering of different types of bonding between the triarylamine electron donor and the conjugated DTT π-bridge by the introduction of single, double, and triple bonds. As a result, with only 1.3 μm transparent and 2.5-μm TiO 2 scattering layers, the triple-bond sensitizer (T-DAHTDTT) shows the highest power conversion efficiency (η = 8.4%; V OC = 0.73 V, J SC = 15.4 mA·cm -2 , and FF = 0.75) in an iodine electrolyte system under one solar illumination (AM 1.5, 1000 W·m -2 ), followed by the single-bond sensitizer (S-DAHTDTT) (η = 7.6%) and the double-bond sensitizer (D-DAHTDTT) (η = 6.4%). We suggest that the superior performance of T-DAHTDTT comes from enhanced intramolecular charge transfer (ICT) induced by the triple bond. Consequently, T-DAHTDTT exhibits the most active photoelectron injection and charge transport on a TiO 2 film during operation, which leads to the highest photocurrent density among the systems studied. We analyzed these correlations mainly in terms of charge injection efficiency, level of photocharge storage, and charge-transport kinetics. This study suggests that the molecular engineering of a triple bond between the electron donor and the π-bridge of a sensitizer increases the performance of dye-sensitized solar cell (DSC) with a thin photoactive film by enhancing not only J SC through improved ICT but also V OC through the evenly distributed sensitizer surface coverage.

Effect of swirl on the performance and combustion of a biogas fuelled spark ignition engine

International Nuclear Information System (INIS)

Porpatham, E.; Ramesh, A.; Nagalingam, B.

2013-01-01

Highlights: • Tests were conducted on a biogas fuelled SI engine with normal and masked valve. • Improvement in brake power and brake thermal efficiency with masked valve. • Lean misfire limit is extended with enhanced swirl from 0.68 to 0.65. • Enhanced swirl decreases HC level from1530 ppm to 1340 ppm and increases NO emission from 2250 ppm to 3440 ppm. • The reduction in ignition delay and higher heat release rate with enhanced swirl. - Abstract: The influence of swirl on the performance, emissions and combustion in a constant speed Spark Ignition (SI) engine was studied experimentally. A single cylinder diesel engine was modified to operate as a biogas operated spark ignition engine. The engine was operated at 1500 rpm at throttle opening of 25% and 100% at various equivalence ratios. The tests covered a range of equivalence ratios from rich to lean operating limits and also at an optimum compression ratio of 13:1 with normal and masked intake valve to enhance swirl. The spark timing was set to MBT (Minimum advance for Best Torque). It was found that masked valve configuration enhanced the power output and brake thermal efficiency at full throttle. The lean limit of combustion also got extended. Heat release rates indicated enhanced combustion rates with masked valve, which are mainly responsible for the improvement in thermal efficiency. NO level increased with masked valve as compared to normal configuration. The spark timings were to be retarded by about 6 °CA and 4 °CA when compared to normal configuration at 25% and 100% throttle respectively

Enhancing Engineering Students’ Learning in an Environmental Microbiology Course

Directory of Open Access Journals (Sweden)

Zhi Zhou

2012-08-01

Full Text Available While environmental engineering students have gained some knowledge of biogeochemical cycles and sewage treatment, most of them haven’t learned microbiology previously and usually have difficulty in learning environmental microbiology because microbiology deals with invisible living microorganisms instead of visible built environment. Many teaching techniques can be used to enhance students’ learning in microbiology courses, such as lectures, animations, videos, small-group discussions, and active learning techniques. All of these techniques have been applied in the engineering class, but the results indicate that these techniques are often inadequate for students. Learning difficulties have to be identified to enhance students’ learning.

An Ethical Study on the Uses of Enhancement Genetic Engineering

Science.gov (United States)

Kawakita, Koji

A variety of biomedical technologies are being developed that can be used for purposes other than treating diseases. Such “enhancement technologies” can be used to improve our own and future generation's life-chances. While these technologies can help people in many ways, their use raises important ethical issues. Some arguments for anti-enhancement as well as pro-enhancement seem to rest, however, on shaky foundation. Both company engineers and the general public had better learn more from technological, economical and philosophical histories. For such subjects may provide engineers with less opportunities of technological misuses and more powers of self-esteem in addition to self-control.

Effects of synergetic and antagonistic additive elements on the thermal performance of engine oils at various bulk temperatures

International Nuclear Information System (INIS)

Abou-Ziyan, H.; Mahmoud, M.; Al-Ajmi, R.; Shedid, M.

2015-01-01

This paper reports effects of additive elements on thermal performance of engine oils during cooling of different engine parts at bulk temperatures from 40 to 150 °C and average wall superheat of 100 °C. The analysis is performed using a back propagation neural network that was trained on experimentally obtained sub-cooled boiling data of engine oils. The results demonstrate that sodium, boron, molybdenum, magnesium and barium additive elements are thermally synergetic while phosphorous, zinc, calcium and silicon elements are thermally antagonistic. Experimental thermal performance of oils could potentially be improved by increasing the concentration of synergetic additive elements or decreasing antagonistic additive elements concentration. - Highlights: • Oil additives enhance lubrication properties but may hinder oil thermal performance. • Sodium, boron, molybdenum, magnesium and barium additives enhance heat transfer. • Additives containing phosphorous, zinc, calcium and silicon hinder the heat transfer. • Oil thermal performance is improved by changing some oil additives concentrations. • Some additives are highly sensitive to interaction with other additives in the oil.

Fuel Combustion and Engine Performance | Transportation Research | NREL

Science.gov (United States)

Fuel Combustion and Engine Performance Fuel Combustion and Engine Performance Photo of a gasoline emissions in advanced engine technologies. Photo by Dennis Schroeder, NREL NREL's combustion research and combustion and engine research activities include: Developing experimental and simulation research platforms

Novel biofuel formulations for enhanced vehicle performance

Energy Technology Data Exchange (ETDEWEB)

Miller, Dennis [Michigan State Univ., East Lansing, MI (United States); Narayan, Ramani [Michigan State Univ., East Lansing, MI (United States); Berglund, Kris [Michigan State Univ., East Lansing, MI (United States); Lira, Carl [Michigan State Univ., East Lansing, MI (United States); Schock, Harold [Michigan State Univ., East Lansing, MI (United States); Jaberi, Farhad [Michigan State Univ., East Lansing, MI (United States); Lee, Tonghun [Michigan State Univ., East Lansing, MI (United States); Anderson, James [Michigan State Univ., East Lansing, MI (United States); Wallington, Timothy [Michigan State Univ., East Lansing, MI (United States); Kurtz, Eric [Michigan State Univ., East Lansing, MI (United States); Ruona, Will; Hass, Heinz

2013-08-30

This interdisciplinary research program at Michigan State University, in collaboration with Ford Motor Company, has explored the application of tailored or designed biofuels for enhanced vehicle performance and reduced emissions. The project has included a broad range of experimental research, from chemical and biological formation of advanced biofuel components to multicylinder engine testing of blended biofuels to determine engine performance parameters. In addition, the project included computation modeling of biofuel physical and combustion properties, and simulation of advanced combustion modes in model engines and in single cylinder engines. Formation of advanced biofuel components included the fermentation of five-carbon and six-carbon sugars to n-butanol and to butyric acid, two four-carbon building blocks. Chemical transformations include the esterification of the butyric acid produced to make butyrate esters, and the esterification of succinic acid with n-butanol to make dibutyl succinate (DBS) as attractive biofuel components. The conversion of standard biodiesel, made from canola or soy oil, from the methyl ester to the butyl ester (which has better fuel properties), and the ozonolysis of biodiesel and the raw oil to produce nonanoate fuel components were also examined in detail. Physical and combustion properties of these advanced biofuel components were determined during the project. Physical properties such as vapor pressure, heat of evaporation, density, and surface tension, and low temperature properties of cloud point and cold filter plugging point were examined for pure components and for blends of components with biodiesel and standard petroleum diesel. Combustion properties, particularly emission delay that is the key parameter in compression ignition engines, was measured in the MSU Rapid Compression Machine (RCM), an apparatus that was designed and constructed during the project simulating the compression stroke of an internal combustion

Studies on an advanced repository system with enhanced engineered barriers (a framework)

International Nuclear Information System (INIS)

Fujiwara, A.; Tashiro, S.; Ikari, S.; Suzuki, A.

1993-01-01

In order to propose advanced designs of repositories with enhanced engineered barriers of relatively high radioactive wastes such as burnable poisons, channel boxes, control rods and highly irradiated metals, studies started in 1987 and completed the first phase in 1992. This paper presents the framework and brief results of the first phase. The studies set preliminary design concepts of the repositories with various combinations with engineered barriers and natural barriers for different models and locations such as a silo type in shallow land or a tunnel type in intermediate depth. Through the designs, four component technics were picked up and studied for (1) construction of the components in repository; (2) performance evaluation to realize repository design; (3) improvement of circumstances inside or around repository; and (4) surveillance of repository performance to realize the repository designs. Finally, some repository systems were provided using obtained results, and then the applicability and the economy were evaluated. The studies will continue to the second phase focusing on the long-term performance of the repositories

Categorization of web pages - Performance enhancement to search engine

Digital Repository Service at National Institute of Oceanography (India)

Lakshminarayana, S.

of Artificial Intelligence, Volume III. Los Altos, CA.: William Kaufmann. pp 1-74. 18. Brin, S. & Page, L. (1998). The anatomy of a large scale hyper-textual web search engine. In Proceedings of the seventh World Wide Web conference, Brisbane, Australia. 19...

Performances Study of a Hybrid Rocket Engine

Directory of Open Access Journals (Sweden)

Adrian-Nicolae BUTURACHE

2018-06-01

Full Text Available This paper presents a study which analyses the functioning and performances optimization of a hybrid rocket engine based on gaseous oxygen and polybutadiene polymer (HTPB. Calculations were performed with NASA CEA software in order to obtain the parameters resulted following the combustion process. Using these parameters, the main parameters of the hybrid rocket engine were optimized. Using the calculus previously stated, an experimental rocket engine producing 100 N of thrust was pre-dimensioned, followed by an optimization of the rocket engine as a function of several parameters. Having the geometry and the main parameters of the hybrid rocket engine combustion process, numerical simulations were performed in the CFX – ANSYS commercial software, which allowed visualizing the flow field and the jet expansion. Finally, the analytical calculus was validated through numerical simulations.

A high performance thermoacoustic Stirling-engine

Energy Technology Data Exchange (ETDEWEB)

Tijani, M.E.H.; Spoelstra, S. [Energy research Centre of the Netherlands (ECN), PO Box 1, 1755 ZG Petten (Netherlands)

2011-11-10

In thermoacoustic systems heat is converted into acoustic energy and vice versa. These systems use inert gases as working medium and have no moving parts which makes the thermoacoustic technology a serious alternative to produce mechanical or electrical power, cooling power, and heating in a sustainable and environmentally friendly way. A thermoacoustic Stirling heat engine is designed and built which achieves a record performance of 49% of the Carnot efficiency. The design and performance of the engine is presented. The engine has no moving parts and is made up of few simple components.

Concurrently adjusting interrelated control parameters to achieve optimal engine performance

Science.gov (United States)

Jiang, Li; Lee, Donghoon; Yilmaz, Hakan; Stefanopoulou, Anna

2015-12-01

Methods and systems for real-time engine control optimization are provided. A value of an engine performance variable is determined, a value of a first operating condition and a value of a second operating condition of a vehicle engine are detected, and initial values for a first engine control parameter and a second engine control parameter are determined based on the detected first operating condition and the detected second operating condition. The initial values for the first engine control parameter and the second engine control parameter are adjusted based on the determined value of the engine performance variable to cause the engine performance variable to approach a target engine performance variable. In order to cause the engine performance variable to approach the target engine performance variable, adjusting the initial value for the first engine control parameter necessitates a corresponding adjustment of the initial value for the second engine control parameter.

Nanodomain Engineered (K, Na)NbO3 Lead-Free Piezoceramics: Enhanced Thermal and Cycling Reliabilities

DEFF Research Database (Denmark)

Yao, Fang-Zhou; Wang, Ke; Cheng, Li-Qian

2015-01-01

- based materials, accepting the drawbacks of high temperature and cycling instabilities. Here, we present that CaZrO3-modified (K, Na)NbO3 piezoceramics not only possess excellent performance at ambient conditions benefiting from nanodomain engineering, but also exhibit superior stability against......The growing environmental concerns have been pushing the development of viable green alternatives for lead-based piezoceramics to be one of the priorities in functional ceramic materials. A polymorphic phase transition has been utilized to enhance piezoelectric properties of lead-free (K, Na)NbO3...... temperature fluctuation and electrical fatigue cycling. It was found that the piezoelectric coefficient d33 is temperature independent under 4 kV/mm, which can be attributed to enhanced thermal stability of electric field engineered domain configuration; whereas the electric field induced strain exhibits...

ADVANCED COMPRESSOR ENGINE CONTROLS TO ENHANCE OPERATION, RELIABILITY AND INTEGRITY

Energy Technology Data Exchange (ETDEWEB)

Gary D. Bourn; Jess W. Gingrich; Jack A. Smith

2004-03-01

This document is the final report for the ''Advanced Compressor Engine Controls to Enhance Operation, Reliability, and Integrity'' project. SwRI conducted this project for DOE in conjunction with Cooper Compression, under DOE contract number DE-FC26-03NT41859. This report addresses an investigation of engine controls for integral compressor engines and the development of control strategies that implement closed-loop NOX emissions feedback.

Performance of engineered barriers

International Nuclear Information System (INIS)

Rajaram, V.; Dean, P.V.; McLellan, S.A.

1997-01-01

Engineered barriers, both vertical and horizontal, have been used to isolate hazardous wastes from contact, precipitation, surface water and groundwater. The primary objective of this study was to determine the performance of subsurface barriers installed throughout the U.S. over the past 20 years to contain hazardous wastes. Evaluation of Resource Conservation and Recovery Act (RCRA) Subtitle C or equivalent caps was a secondary objective. A nationwide search was launched to select hazardous waste sites at which vertical barrier walls and/or caps had been used as the containment method. None of the sites selected had an engineered floor. From an initial list of 130 sites, 34 sites were selected on the basis of availability of monitoring data for detailed analysis of actual field performance. This paper will briefly discuss preliminary findings regarding the design, construction quality assurance/construction quality control (CQA/CQC), and monitoring at the 34 sites. In addition, the short-term performance of these sites (less than 5 years) is presented since very little long-term performance data was available

Experimental study of dual fuel engine performance using variable LPG composition and engine parameters

International Nuclear Information System (INIS)

Elnajjar, Emad; Selim, Mohamed Y.E.; Hamdan, Mohammad O.

2013-01-01

Highlights: • The effect of using variable LPG is studied. • Five fuels with propane to butane % volume ratio are: 100-70-55-25-0. • 100% Propane composition shows the highest noise levels with similar performance. • At 45° BTDC injection timing 55% Propane LPG the only fuel experience knocking. • LPG fuels gave similar engine performance, with differences in levels of noise. - Abstract: The present work investigates experimentally the effect of LPG fuel with different composition and engine parameters on the performance of a dual compression engine. Five different blends of LPG fuels are used with Propane to Butane volume ratio of 100:0, 70:30, 55:45, 25:75, and 0:100. A single cylinder, naturally aspirated, four strokes, indirectly injected, water cooled modified Ricardo E6 engine, is used in this study. The study is carried out by measuring the cylinder pressure, engine load, engine speed, crank angle, and the fuel’s flow rate. The engine performance under variable LPG fuel composition, engine load, pilot fuel injection timing, compression ratio, pilot fuel mass and engine speed, are estimated by comparing the following engine parameters: the cylinder maximum pressure, the indicated mean effective pressure, the maximum rate of pressure rise, and the thermal efficiency. The experimental data indicates that the engine parameters are playing a major role on the engine’s performance. Different LPG fuel composition did not show a major effect on the engine efficiency but directly impacted the levels of generated combustion noise

Enabling performance skills: Assessment in engineering education

Science.gov (United States)

Ferrone, Jenny Kristina

Current reform in engineering education is part of a national trend emphasizing student learning as well as accountability in instruction. Assessing student performance to demonstrate accountability has become a necessity in academia. In newly adopted criterion proposed by the Accreditation Board for Engineering and Technology (ABET), undergraduates are expected to demonstrate proficiency in outcomes considered essential for graduating engineers. The case study was designed as a formative evaluation of freshman engineering students to assess the perceived effectiveness of performance skills in a design laboratory environment. The mixed methodology used both quantitative and qualitative approaches to assess students' performance skills and congruency among the respondents, based on individual, team, and faculty perceptions of team effectiveness in three ABET areas: Communications Skills. Design Skills, and Teamwork. The findings of the research were used to address future use of the assessment tool and process. The results of the study found statistically significant differences in perceptions of Teamwork Skills (p performance skills, such as teamwork, among freshman engineering students; (2) incorporate feedback into the learning process; (3) strengthen the assessment process with a follow-up plan that specifically targets performance skill deficiencies, and (4) integrate the assessment instrument and practice with ongoing curriculum development. The findings generated by this study provides engineering departments engaged in assessment activity, opportunity to reflect, refine, and develop their programs as it continues. It also extends research on ABET competencies of engineering students in an under-investigated topic of factors correlated with team processes, behavior, and student learning.

Hydrogen engine performance analysis project. Second annual report

Energy Technology Data Exchange (ETDEWEB)

Adt, Jr., R. R.; Swain, M. R.; Pappas, J. M.

1980-01-01

Progress in a 3 year research program to evaluate the performance and emission characteristics of hydrogen-fueled internal combustion engines is reported. Fifteen hydrogen engine configurations will be subjected to performance and emissions characterization tests. During the first two years, baseline data for throttled and unthrottled, carburetted and timed hydrogen induction, Pre IVC hydrogen-fueled engine configurations, with and without exhaust gas recirculation (EGR) and water injection, were obtained. These data, along with descriptions of the test engine and its components, the test apparatus, experimental techniques, experiments performed and the results obtained, are given. Analyses of other hydrogen-engine project data are also presented and compared with the results of the present effort. The unthrottled engine vis-a-vis the throttled engine is found, in general, to exhibit higher brake thermal efficiency. The unthrottled engine also yields lower NO/sub x/ emissions, which were found to be a strong function of fuel-air equivalence ratio. (LCL)

Performance comparison of a novel configuration of beta-type Stirling engines with rhombic drive engine

International Nuclear Information System (INIS)

Solmaz, Hamit; Karabulut, Halit

2014-01-01

Highlights: • The paper describes a novel arrangement of a beta-type Stirling engine. • Its performance was compared with rhombic drive engine. • The power output of the engine was found to be greater than rhombic drive. • Efficiency was found to be higher than rhombic drive at the same working fluid mass. • Efficiency was found to be lower than rhombic drive at the same charge pressure. - Abstract: This study presents a beta type Stirling engine mechanism and its performance analysis. The displacer motion of the engine is performed by a lever mechanism. The performance of the engine was investigated via comparing with a rhombic-drive engine possessing an equal sided rhombic. Comparison was made for kinematic behaviors, power and thermal efficiency. For comparison; the piston swept volume, the inner heat transfer area, the hot and cold end temperatures, the inner heat transfer coefficient, charge pressure and dead volumes were kept equal for both engines. As working fluid the helium was used. Thermodynamic treatments of engines were performed via the nodal analysis. The power of the lever driven engine was found to be greater than the power of the rhombic drive engine. Under the equal charge pressure, the thermal efficiency of the lever driven engine was found to be lower than the efficiency of the rhombic drive engine however, under the equal working fluid mass the thermal efficiency of the lever driven engine was found to be greater than that of the rhombic drive engine. The external volume and mass of the lever driven engine is lower than the rhombic drive engine

Enhancing electronic and optoelectronic performances of tungsten diselenide by plasma treatment.

Science.gov (United States)

Xie, Yuan; Wu, Enxiu; Hu, Ruixue; Qian, Shuangbei; Feng, Zhihong; Chen, Xuejiao; Zhang, Hao; Xu, Linyan; Hu, Xiaodong; Liu, Jing; Zhang, Daihua

2018-06-21

Transition metal dichalcogenides (TMDCs) have recently become spotlighted as nanomaterials for future electronic and optoelectronic devices. In this work, we develop an effective approach to enhance the electronic and optoelectronic performances of WSe2-based devices by N2O plasma treatment. The hole mobility and sheet density increase by 2 and 5 orders of magnitude, reaching 110 cm2 V-1 s-1 and 2.2 × 1012 cm-2, respectively, after the treatment. At the same time, the contact resistance (Rc) between WSe2 and its metal electrode drop by 5 orders of magnitude from 1.0 GΩ μm to 28.4 kΩ μm. The WSe2 photoconductor exhibits superior performance with high responsivity (1.5 × 105 A W-1), short response time (106). We have also built a lateral p-n junction on a single piece of WSe2 flake by selective plasma exposure. The junction reaches an exceedingly high rectifying ratio of 106, an excellent photoresponsivity of 2.49 A W-1 and a fast response of 8 ms. The enhanced optoelectronic performance is attributed to band-engineering through the N2O plasma treatment, which can potentially serve as an effective and versatile approach for device engineering and optimization in a wide range of electronic and optoelectronic devices based on 2D materials.

Self-Control and Academic Performance in Engineering

Science.gov (United States)

Honken, Nora; Ralston, Patricia A.; Tretter, Thomas R.

2016-01-01

Self-control has been related to positive student outcomes including academic performance of college students. Because of the critical nature of the first semester academic performance for engineering students in terms of retention and persistence in pursuing an engineering degree, this study investigated the relationship between freshmen…

Spark Ignition Engine Combustion, Performance and Emission Products from Hydrous Ethanol and Its Blends with Gasoline

Directory of Open Access Journals (Sweden)

Musaab O. El-Faroug

2016-11-01

Full Text Available This paper reviews the serviceability of hydrous ethanol as a clean, cheap and green renewable substitute fuel for spark ignition engines and discusses the comparative chemical and physical properties of hydrous ethanol and gasoline fuels. The significant differences in the properties of hydrous ethanol and gasoline fuels are sufficient to create a significant change during the combustion phase of engine operation and consequently affect the performance of spark-ignition (SI engines. The stability of ethanol-gasoline-water blends is also discussed. Furthermore, the effects of hydrous ethanol, and its blends with gasoline fuel on SI engine combustion characteristics, cycle-to-cycle variations, engine performance parameters, and emission characteristics have been highlighted. Higher water solubility in ethanol‑gasoline blends may be obviously useful and suitable; nevertheless, the continuous ability of water to remain soluble in the blend is significantly affected by temperature. Nearly all published engine experimental results showed a significant improvement in combustion characteristics and enhanced engine performance for the use of hydrous ethanol as fuel. Moreover, carbon monoxide and oxides of nitrogen emissions were also significantly decreased. It is also worth pointing out that unburned hydrocarbon and carbon dioxide emissions were also reduced for the use of hydrous ethanol. However, unregulated emissions such as acetaldehyde and formaldehyde were significantly increased.

Case-based Reasoning for Automotive Engine Performance Tune-up

International Nuclear Information System (INIS)

Vong, C. M.; Huang, H.; Wong, P. K.

2010-01-01

The automotive engine performance tune-up is greatly affected by the calibration of its electronic control unit (ECU). The ECU calibration is traditionally done by trial-and-error method. This traditional method consumes a large amount of time and money because of a large number of dynamometer tests. To resolve this problem, case based reasoning (CBR) is employed, so that an existing and effective ECU setup can be adapted to fit another similar class of engines. The adaptation procedure is done through a more sophisticated step called case-based adaptation (CBA)[1, 2]. CBA is an effective knowledge management tool, which can interactively learn the expert adaptation knowledge. The paper briefly reviews the methodologies of CBR and CBA. Then the application to ECU calibration is described via a case study. With CBR and CBA, the efficiency of calibrating an ECU can be enhanced. A prototype system has also been developed to verify the usefulness of CBR in ECU calibration.

Engineering Self-Efficacy Contributing to the Academic Performance of AMAIUB Engineering Students: A Qualitative Investigation

Science.gov (United States)

Aleta, Beda T.

2016-01-01

This research study aims to determine the factors of engineering skills self- efficacy sources contributing on the academic performance of AMAIUB engineering students. Thus, a better measure of engineering self-efficacy is needed to adequately assess engineering students' beliefs in their capabilities to perform tasks in their engineering…

Evolutionary engineering to enhance starter culture performance in food fermentations.

Science.gov (United States)

Bachmann, Herwig; Pronk, Jack T; Kleerebezem, Michiel; Teusink, Bas

2015-04-01

Microbial starter cultures are essential for consistent product quality and functional properties such as flavor, texture, pH or the alcohol content of various fermented foods. Strain improvement programs to achieve desired properties in starter cultures are diverse, but developments in next-generation sequencing lead to an increased interest in evolutionary engineering of desired phenotypes. We here discuss recent developments of strain selection protocols and how computational approaches can assist such experimental design. Furthermore the analysis of evolved phenotypes and possibilities with complex consortia are highlighted. Studies carried out with mainly yeast and lactic acid bacteria demonstrate the power of evolutionary engineering to deliver strains with novel phenotypes as well as insight into underlying mechanisms. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of Engine Cooling Water Temperature on Performance and Emission Characteristics of a Ci Engine Operated with Biofuel Blend

Directory of Open Access Journals (Sweden)

Abul Hossain

2017-03-01

Full Text Available The temperature of the coolant is known to have significant influence on engine performance and emissions. Whereas existing literature describes the effects of coolant temperature in engines using fossil derived fuels, very few studies have investigated these effects when biofuel is used. In this study, Jatropha oil was blended separately with ethanol and butanol. It was found that the 80% jatropha oil + 20% butanol blend was the most suitable alternative, as its properties were closest to that of fossil diesel. The coolant temperature was varied between 50°C and 95°C. The combustion process enhanced for both diesel and biofuel blend, when the coolant temperature was increased. The carbon dioxide emissions for both diesel and biofuel blend were observed to increase with temperature. The carbon monoxide, oxygen and lambda values were observed to decrease with temperature. When the engine was operated using diesel, nitrogen oxides emissions correlated in an opposite manner to smoke opacity; however, nitrogen oxides emissions and smoke opacity correlated in an identical manner for biofuel blend. Brake specific fuel consumption was observed to decrease as the temperature was increased and was higher on average when the biofuel was used. The study concludes that both biofuel blend and fossil diesel produced identical correlations between coolant temperature and engine performance. The trends of nitrogen oxides and smoke emissions with cooling temperatures were not identical to fossil diesel when biofuel blend was used in the engine.

Direct comparasion of an engine working under Otto, Miller end Diesel cycles : thermodynamic analysis and real engine performance

OpenAIRE

Ribeiro, Bernardo Sousa; Martins, Jorge

2007-01-01

One of the ways to improve thermodynamic efficiency of Spark Ignition engines is by the optimisation of valve timing and lift and compression ratio. The throttleless engine and the Miller cycle engine are proven concepts for efficiency improvements of such engines. This paper reports on an engine with variable valve timing (VVT) and variable compression ratio (VCR) in order to fulfill such an enhancement of efficiency. Engine load is controlled by the valve opening per...

Performance and driveline analyses of engine capacity in range extender engine hybrid vehicle

Science.gov (United States)

Praptijanto, Achmad; Santoso, Widodo Budi; Nur, Arifin; Wahono, Bambang; Putrasari, Yanuandri

2017-01-01

In this study, range extender engine designed should be able to meet the power needs of a power generator of hybrid electrical vehicle that has a minimum of 18 kW. Using this baseline model, the following range extenders will be compared between conventional SI piston engine (Baseline, BsL), engine capacity 1998 cm3, and efficiency-oriented SI piston with engine capacity 999 cm3 and 499 cm3 with 86 mm bore and stroke square gasoline engine in the performance, emission prediction of range extender engine, standard of charge by using engine and vehicle simulation software tools. In AVL Boost simulation software, range extender engine simulated from 1000 to 6000 rpm engine loads. The highest peak engine power brake reached up to 38 kW at 4500 rpm. On the other hand the highest torque achieved in 100 Nm at 3500 rpm. After that using AVL cruise simulation software, the model of range extended electric vehicle in series configuration with main components such as internal combustion engine, generator, electric motor, battery and the arthemis model rural road cycle was used to simulate the vehicle model. The simulation results show that engine with engine capacity 999 cm3 reported the economical performances of the engine and the emission and the control of engine cycle parameters.

Design and Performance Evaluation of an Electro-Hydraulic Camless Engine Valve Actuator for Future Vehicle Applications.

Science.gov (United States)

Nam, Kanghyun; Cho, Kwanghyun; Park, Sang-Shin; Choi, Seibum B

2017-12-18

This paper details the new design and dynamic simulation of an electro-hydraulic camless engine valve actuator (EH-CEVA) and experimental verification with lift position sensors. In general, camless engine technologies have been known for improving fuel efficiency, enhancing power output, and reducing emissions of internal combustion engines. Electro-hydraulic valve actuators are used to eliminate the camshaft of an existing internal combustion engines and used to control the valve timing and valve duration independently. This paper presents novel electro-hydraulic actuator design, dynamic simulations, and analysis based on design specifications required to satisfy the operation performances. An EH-CEVA has initially been designed and modeled by means of a powerful hydraulic simulation software, AMESim, which is useful for the dynamic simulations and analysis of hydraulic systems. Fundamental functions and performances of the EH-CEVA have been validated through comparisons with experimental results obtained in a prototype test bench.

Influence of hydrox on spark ignition engine performance

International Nuclear Information System (INIS)

Naude, A.F.

2003-01-01

An experimental investigation was performed on the influence of the addition of small quantities of Hydrox (hydrogen and oxygen) as generated through electrolysis of water on the performance of a spark ignition engine. A Mazda 1600 cc fuel injected engine connected to a Superflow SF901 dynamometer system was used in this project. The engine was also equipped with a Unichip engine management system in order to enable changes in the spark timing and the amount of fuel injected. Hydrox was generated by an electrolysis process that could either be powered by the engine's alternator or from a separate power source. This hydrox gas produced from the electrolyzer was introduced into the engine's intake manifold and the influence of this was measured on the engine's performance, emissions and fuel consumption. For these tests a typical load condition as experienced for a light passenger car vehicle driven at 100 km/h on the open road was simulated. Typical results for the change in emissions with the hydrox introduction showed a significant reduction in hydrocarbons at lean air-fuel ratio operation of the engine. Additionally with the electrolysis process being driven by the engine a small improvement in fuel consumption was experienced. (author)

Morphology engineering of high performance binary oxide electrodes.

Science.gov (United States)

Chen, Kunfeng; Sun, Congting; Xue, Dongfeng

2015-01-14

Advances in materials have preceded almost every major technological leap since the beginning of civilization. On the nanoscale and microscale, mastery over the morphology, size, and structure of a material enables control of its properties and enhancement of its usefulness for a given application, such as energy storage. In this review paper, our aim is to present a review of morphology engineering of high performance oxide electrode materials for electrochemical energy storage. We begin with the chemical bonding theory of single crystal growth to direct the growth of morphology-controllable materials. We then focus on the growth of various morphologies of binary oxides and their electrochemical performances for lithium ion batteries and supercapacitors. The morphology-performance relationships are elaborated by selecting examples in which there is already reasonable understanding for this relationship. Based on these comprehensive analyses, we proposed colloidal supercapacitor systems beyond morphology control on the basis of system- and ion-level design. We conclude this article with personal perspectives on the directions toward which future research in this field might take.

Enhancing Systems Engineering Education Through Case Study Writing

Science.gov (United States)

Stevens, Jennifer Stenger

2016-01-01

Developing and refining methods for teaching systems engineering is part of Systems Engineering grand challenges and agenda for research in the SE research community. Retention of systems engineering knowledge is a growing concern in the United States as the baby boom generation continues to retire and the faster pace of technology development does not allow for younger generations to gain experiential knowledge through years of practice. Government agencies, including the National Aeronautics and Space Administration (NASA), develop their own curricula and SE leadership development programs to "grow their own" systems engineers. Marshall Space Flight Center (MSFC) conducts its own Center-focused Marshall Systems Engineering Leadership Development Program (MSELDP), a competitive program consisting of coursework, a guest lecture series, and a rotational assignment into an unfamiliar organization engaged in systems engineering. Independently, MSFC developed two courses to address knowledge retention and sharing concerns: Real World Marshall Mission Success course and its Case Study Writers Workshop and Writers Experience. Teaching case study writing and leading students through a hands-on experience at writing a case study on an SE topic can enhance SE training and has the potential to accelerate the transfer of experiential knowledge. This paper is an overview of the pilot experiences with teaching case study writing, its application in case study-based learning, and identifies potential areas of research and application for case study writing in systems engineering education.

Self-Regulated Learning Strategies of Engineering College Students While Learning Electric Circuit Concepts with Enhanced Guided Notes

Science.gov (United States)

Lawanto, Oenardi; Santoso, Harry

2013-01-01

The current study evaluated engineering college students' self-regulated learning (SRL) strategies while learning electric circuit concepts using enhanced guided notes (EGN). Our goal was to describe how students exercise SRL strategies and how their grade performance changes after using EGN. Two research questions guided the study: (1) To what…

Performing Verification and Validation in Reuse-Based Software Engineering

Science.gov (United States)

Addy, Edward A.

1999-01-01

The implementation of reuse-based software engineering not only introduces new activities to the software development process, such as domain analysis and domain modeling, it also impacts other aspects of software engineering. Other areas of software engineering that are affected include Configuration Management, Testing, Quality Control, and Verification and Validation (V&V). Activities in each of these areas must be adapted to address the entire domain or product line rather than a specific application system. This paper discusses changes and enhancements to the V&V process, in order to adapt V&V to reuse-based software engineering.

The effect of additives on properties, performance and emission of biodiesel fuelled compression ignition engine

International Nuclear Information System (INIS)

Rashedul, H.K.; Masjuki, H.H.; Kalam, M.A.; Ashraful, A.M.; Ashrafur Rahman, S.M.; Shahir, S.A.

2014-01-01

Highlights: • Fuel additives significantly improve the quality of biodiesel and its blends. • Fuel additives used to enhance biodiesel properties. • Fuel saving from optimized vehicle performance and economy with the use of additives. • Emission reduction from fuel system cleanliness and combustion optimization. - Abstract: With growing concern over greenhouse gases there is increasing emphasis on reducing CO 2 emissions. Despite engine efficiency improvements plus increased dieselization of the fleet, increasing vehicle numbers results in increasing CO 2 emissions. To reserve this trend the fuel source must be changed to renewable fuels which are CO 2 neutral. As a renewable, sustainable and alternative fuel for compression ignition engines, biodiesel is widely accepted as comparable fuel to diesel in diesel engines. This is due to several factors like decreasing the dependence on imported petroleum, reducing global warming, increasing lubricity, and reducing substantially the exhaust emissions from diesel engine. However, there is a major disadvantage in the use of biodiesel as it has lower heating value, higher density and higher viscosity, higher fuel consumption and higher NO X emission, which limits its application. Here fuel additives become essential and indispensable tools not only to minimize these drawbacks but also generate specified products to meet the regional and international standards. Fuel additives can contribute towards fuel economy and emission reduction either directly or indirectly. Their use enable vehicle performance to be maintained at, or near, optimum over the lifetime of the vehicle. A variety of additives are used in automotive biodiesel fuel to meet specification limits and to enhance quality. For example, metal based additives, oxygenated additives, antioxidants, cetane number improvers, lubricity improvers and cold flow improvers are used to meet specifications and quality. This article is a literature review of the effect

PRACA Enhancement Pilot Study Report: Engineering for Complex Systems Program (formerly Design for Safety), DFS-IC-0006

Science.gov (United States)

Korsmeyer, David; Schreiner, John

2002-01-01

This technology evaluation report documents the findings and recommendations of the Engineering for Complex Systems Program (formerly Design for Safety) PRACA Enhancement Pilot Study of the Space Shuttle Program's (SSP's) Problem Reporting and Corrective Action (PRACA) System. A team at NASA Ames Research Center (ARC) performed this Study. This Study was initiated as a follow-on to the NASA chartered Shuttle Independent Assessment Team (SIAT) review (performed in the Fall of 1999) which identified deficiencies in the current PRACA implementation. The Pilot Study was launched with an initial qualitative assessment and technical review performed during January 2000 with the quantitative formal Study (the subject of this report) started in March 2000. The goal of the PRACA Enhancement Pilot Study is to evaluate and quantify the technical aspects of the SSP PRACA systems and recommend enhancements to address deficiencies and in preparation for future system upgrades.

Novel technique for enhancement of diesel fuel: Impact of aqueous alumina nano-fluid on engine's performance and emissions

Directory of Open Access Journals (Sweden)

Miqdam Tariq Chaichan

2017-09-01

Full Text Available Nanofluids are suspensions of nanoparticles mixed in liquids and show significant enhancement in some thermophysical and combustion properties of the resulting suspension. In this study, the changes in the performance and emissions characteristics of a conventional diesel engine are verified experimentally using the combustion of a mixture of nanofluid (water and Al2O3 and conventional Iraqi diesel fuel. The nano-Al2O3 (51 nm diameter was used in this study; multiple weight ratios of this nanoparticle were mixed with water to form a nanoparticle suspension. The weight fractions used were 1%, 3%, 5%, 7%, and 10%. After that, a fixed volume ratio of the resulting suspension (10% was added to the diesel and completely mixed. The results indicate that the addition of the nano-alumina-water suspension has increased the brake thermal efficiency up to 5.5%, and reduced the relative fuel consumption up to 3.94%, compared to diesel fuel. In the analysis of emitted exhaust emissions, CO, HC, NOx, PM and noise emissions, they were found to be lower than diesel fuel, while CO2 emissions increased.

Engineering bacteria for enhanced polyhydroxyalkanoates (PHA biosynthesis

Directory of Open Access Journals (Sweden)

Guo-Qiang Chen

2017-09-01

Full Text Available Polyhydroxyalkanoates (PHA have been produced by some bacteria as bioplastics for many years. Yet their commercialization is still on the way. A few issues are related to the difficulty of PHA commercialization: namely, high cost and instabilities on molecular weights (Mw and structures, thus instability on thermo-mechanical properties. The high cost is the result of complicated bioprocessing associated with sterilization, low conversion of carbon substrates to PHA products, and slow growth of microorganisms as well as difficulty of downstream separation. Future engineering on PHA producing microorganisms should be focused on contamination resistant bacteria especially extremophiles, developments of engineering approaches for the extremophiles, increase on carbon substrates to PHA conversion and controlling Mw of PHA. The concept proof studies could still be conducted on E. coli or Pseudomonas spp. that are easily used for molecular manipulations. In this review, we will use E. coli and halophiles as examples to show how to engineer bacteria for enhanced PHA biosynthesis and for increasing PHA competitiveness.

Enhancing the antibacterial performance of orthopaedic implant materials by fibre laser surface engineering

DEFF Research Database (Denmark)

Chan, Chi-Wai; Carson, Louise; Smith, Graham C.

2017-01-01

to the effort on enhancing osseointegration, wear and corrosion resistance of implant materials. In this study, the effects of laser surface treatment on enhancing the antibacterial properties of commercially pure (CP) Ti (Grade 2), Ti6Al4V (Grade 5) and CoCrMo alloy implant materials were studied and compared...... for the first time. Laser surface treatment was performed by a continuous wave (CW) fibre laser with a near-infrared wavelength of 1064 nm in a nitrogen-containing environment. Staphylococcus aureus, commonly implicated in infection associated with orthopaedic implants, was used to investigate the antibacterial...... properties of the laser-treated surfaces. The surface roughness and topography of the laser-treated materials were analysed by a 2D roughness testing and by AFM. The surface morphologies before and after 24 h of bacterial cell culture were captured by SEM, and bacterial viability was determined using live...

Environmental engineering education enhancement

Science.gov (United States)

Caporali, E.

2012-04-01

Since higher education plays a central role in the development of both human beings and modern societies, enhancing social, cultural and economic development, active citizenship, ethical values and expertises for a sustainable growth, environment respectful, the European Commission promotes a wide range of programmes. Among the EC programmes, the TEMPUS - Trans European Mobility Programme for University Studies, with the support of the DG EAC of the European Commission, has contributed to many aspects of general interest for higher education. Curricula harmonization, LifeLong Learning Programme development, ICT use, quality assessment, accreditation, innovation learning methods, growth of networks of institutions trusting each other, are the focused aspects. Such a solid cooperation framework is surely among the main outcomes of the TEMPUS Projects leaded by the University of Firenze UNIFI (Italy), DEREC - Development of Environment and Resources Engineering Curriculum (2005-2008), and its spin-off DEREL - Development of Environment and Resources Engineering Learning (2010-2013), and VICES - Videoconferencing Educational Services (2009-2012). DEREC and DEREL TEMPUS projects, through the co-operation of Universities in Italy, Austria, Germany, Greece, Macedonia, Albania and Serbia, are aimed at the development of first and second level curricula in "Environment and Resources Engineering" at the Ss. Cyril and Methodius University - UKIM Skopje (MK). In the DEREC Project the conditions for offering a joint degree title in the field of Environmental Engineering between UNIFI and UKIM Skopje were fulfilled and a shared educational programme leading to the mutual recognition of degree titles was defined. The DEREL project, as logical continuation of DEREC, is aimed to introduce a new, up-to-date, postgraduate second level curriculum in Environment and Resources Engineering at UKIM Skopje, University of Novi Sad (RS) and Polytechnic University of Tirana (AL). following

Effects of Gas Turbine Component Performance on Engine and Rotary Wing Vehicle Size and Performance

Science.gov (United States)

Snyder, Christopher A.; Thurman, Douglas R.

2010-01-01

In support of the Fundamental Aeronautics Program, Subsonic Rotary Wing Project, further gas turbine engine studies have been performed to quantify the effects of advanced gas turbine technologies on engine weight and fuel efficiency and the subsequent effects on a civilian rotary wing vehicle size and mission fuel. The Large Civil Tiltrotor (LCTR) vehicle and mission and a previous gas turbine engine study will be discussed as a starting point for this effort. Methodology used to assess effects of different compressor and turbine component performance on engine size, weight and fuel efficiency will be presented. A process to relate engine performance to overall LCTR vehicle size and fuel use will also be given. Technology assumptions and levels of performance used in this analysis for the compressor and turbine components performances will be discussed. Optimum cycles (in terms of power specific fuel consumption) will be determined with subsequent engine weight analysis. The combination of engine weight and specific fuel consumption will be used to estimate their effect on the overall LCTR vehicle size and mission fuel usage. All results will be summarized to help suggest which component performance areas have the most effect on the overall mission.

Improving engineers' performance with computers

International Nuclear Information System (INIS)

Purvis, E.E. III

1984-01-01

The problem addressed is how to improve the performance of engineers in the design, operation, and maintenance of nuclear power plants. The application of computer science to this problem offers a challenge in maximizing the use of developments outside the nuclear industry and setting priorities to address the most fruitful areas first. Areas of potential benefits include data base management through design, analysis, procurement, construction, operation maintenance, cost, schedule and interface control and planning, and quality engineering on specifications, inspection, and training

Cementitious Composites Engineered with Embedded Carbon Nanotube Thin Films for Enhanced Sensing Performance

International Nuclear Information System (INIS)

Loh, Kenneth J; Gonzalez, Jesus

2015-01-01

Cementitious composites such as concrete pavements are susceptible to different damage modes, which are primarily caused by repeated loading and long-term deterioration. There is even greater concern that damage could worsen and occur more frequently with the use of heavier vehicles or new aircraft carrying greater payloads. Thus, the objective of this research is to engineer cementitious composites with capabilities of self-sensing or detecting damage. The approach was to enhance the damage sensitivity of cementitious composites by incorporating multi-walled carbon nanotubes (MWNT) as part of the mix design and during casting. However, as opposed to directly dispersing MWNTs in the cement matrix, which is the current state-of-art, MWNT-based thin films were airbrushed and coated onto sand particles. The film-coated sand was then used as part of the mix design for casting mortar specimens. Mortar specimens were subjected to compressive cyclic loading tests while their electrical properties were recorded simultaneously. The results showed that the electrical properties of these cementitious composites designed with film-coated sand exhibited extremely high strain sensitivities. The electrical response was also stable and consistent between specimens. (paper)

Cementitious Composites Engineered with Embedded Carbon Nanotube Thin Films for Enhanced Sensing Performance

Science.gov (United States)

Loh, Kenneth J.; Gonzalez, Jesus

2015-07-01

Cementitious composites such as concrete pavements are susceptible to different damage modes, which are primarily caused by repeated loading and long-term deterioration. There is even greater concern that damage could worsen and occur more frequently with the use of heavier vehicles or new aircraft carrying greater payloads. Thus, the objective of this research is to engineer cementitious composites with capabilities of self-sensing or detecting damage. The approach was to enhance the damage sensitivity of cementitious composites by incorporating multi-walled carbon nanotubes (MWNT) as part of the mix design and during casting. However, as opposed to directly dispersing MWNTs in the cement matrix, which is the current state-of-art, MWNT-based thin films were airbrushed and coated onto sand particles. The film-coated sand was then used as part of the mix design for casting mortar specimens. Mortar specimens were subjected to compressive cyclic loading tests while their electrical properties were recorded simultaneously. The results showed that the electrical properties of these cementitious composites designed with film-coated sand exhibited extremely high strain sensitivities. The electrical response was also stable and consistent between specimens.

Performance Evaluation of an Experimental Turbojet Engine

Science.gov (United States)

Ekici, Selcuk; Sohret, Yasin; Coban, Kahraman; Altuntas, Onder; Karakoc, T. Hikmet

2017-11-01

An exergy analysis is presented including design parameters and performance assessment, by identifying the losses and efficiency of a gas turbine engine. The aim of this paper is to determine the performance of a small turbojet engine with an exergetic analysis based on test data. Experimental data from testing was collected at full-load of small turbojet engine. The turbojet engine exhaust data contains CO2, CO, CH4, H2, H2O, NO, NO2, N2 and O2 with a relative humidity of 35 % for the ambient air of the performed experiments. The evaluated main components of the turbojet engine are the air compressor, the combustion chamber and the gas turbine. As a result of the thermodynamic analysis, exergy efficiencies (based on product/fuel) of the air compressor, the combustion chamber and the gas turbine are 81.57 %, 50.13 % and 97.81 %, respectively. A major proportion of the total exergy destruction was found for the combustion chamber at 167.33 kW. The exergy destruction rates are 8.20 %, 90.70 % and 1.08 % in the compressor, the combustion chamber and the gas turbine, respectively. The rates of exergy destruction within the system components are compared on the basis of the exergy rate of the fuel provided to the engine. Eventually, the exergy rate of the fuel is calculated to be 4.50 % of unusable due to exergy destruction within the compressor, 49.76 % unusable due to exergy destruction within the combustion chamber and 0.59 % unusable due to exergy destruction within the gas turbine. It can be stated that approximately 55 % of the exergy rate of the fuel provided to the engine can not be used by the engine.

Engine performance and emissions using Jatropha curcas, Ceiba pentandra and Calophyllum inophyllum biodiesel in a CI diesel engine

International Nuclear Information System (INIS)

Ong, Hwai Chyuan; Masjuki, H.H.; Mahlia, T.M.I.; Silitonga, A.S.; Chong, W.T.; Yusaf, Talal

2014-01-01

Biodiesel is a recognized replacement for diesel fuel in compressed ignition engines due to its significant environmental benefits. The purpose of this study is to investigate the engine performance and emissions produced from Jatropha curcas, Ceiba pentandra and Calophyllum inophyllum biodiesel in compressed ignition engine. The biodiesel production process and properties are discussed and a comparison of the three biodiesels as well as diesel fuel is undertaken. After that, engine performance and emissions testing was conducted using biodiesel blends 10%, 20%, 30% and 50% in a diesel engine at full throttle load. The engine performance shows that those biodiesel blends are suitable for use in diesel engines. A 10% biodiesel blend shows the best engine performance in terms of engine torque, engine power, fuel consumption and brake thermal efficiency among the all blending ratios for the three biodiesel blends. Biodiesel blends have also shown a significant reduction in CO 2 , CO and smoke opacity with a slight increase in NO x emissions. - Highlights: • The properties of JCME, CPME and CIME fulfill ASTM standard. • Engine performance and emission was conducted for JCME, CPME and CIME. • The B10 is the best engine performance and reduce in exhaust emission

Capacity enhancement of indigenous expansion engine based helium liquefier

Science.gov (United States)

Doohan, R. S.; Kush, P. K.; Maheshwari, G.

2017-02-01

Development of technology and understanding for large capacity helium refrigeration and liquefaction at helium temperature is indispensable for coming-up projects. A new version of helium liquefier designed and built to provide approximately 35 liters of liquid helium per hour. The refrigeration capacity of this reciprocating type expansion engine machine has been increased from its predecessor version with continuous improvement and deficiency debugging. The helium liquefier has been built using components by local industries including cryogenic Aluminum plate fin heat exchangers. Two compressors with nearly identical capacity have been deployed for the operation of system. Together they consume about 110 kW of electric power. The system employs liquid Nitrogen precooling to enhance liquid Helium yield. This paper describes details of the cryogenic expander design improvements, reconfiguration of heat exchangers, performance simulation and their experimental validation.

A Probabilistic Design Methodology for a Turboshaft Engine Overall Performance Analysis

Directory of Open Access Journals (Sweden)

Min Chen

2014-05-01

Full Text Available In reality, the cumulative effect of the many uncertainties in engine component performance may stack up to affect the engine overall performance. This paper aims to quantify the impact of uncertainty in engine component performance on the overall performance of a turboshaft engine based on Monte-Carlo probabilistic design method. A novel probabilistic model of turboshaft engine, consisting of a Monte-Carlo simulation generator, a traditional nonlinear turboshaft engine model, and a probability statistical model, was implemented to predict this impact. One of the fundamental results shown herein is that uncertainty in component performance has a significant impact on the engine overall performance prediction. This paper also shows that, taking into consideration the uncertainties in component performance, the turbine entry temperature and overall pressure ratio based on the probabilistic design method should increase by 0.76% and 8.33%, respectively, compared with the ones of deterministic design method. The comparison shows that the probabilistic approach provides a more credible and reliable way to assign the design space for a target engine overall performance.

WFIRST: Coronagraph Systems Engineering and Performance Budgets

Science.gov (United States)

Poberezhskiy, Ilya; cady, eric; Frerking, Margaret A.; Kern, Brian; Nemati, Bijan; Noecker, Martin; Seo, Byoung-Joon; Zhao, Feng; Zhou, Hanying

2018-01-01

The WFIRST coronagraph instrument (CGI) will be the first in-space coronagraph using active wavefront control to directly image and characterize mature exoplanets and zodiacal disks in reflected starlight. For CGI systems engineering, including requirements development, CGI performance is predicted using a hierarchy of performance budgets to estimate various noise components — spatial and temporal flux variations — that obscure exoplanet signals in direct imaging and spectroscopy configurations. These performance budgets are validated through a robust integrated modeling and testbed model validation efforts.We present the performance budgeting framework used by WFIRST for the flow-down of coronagraph science requirements, mission constraints, and observatory interfaces to measurable instrument engineering parameters.

Performance and emission characteristics of the thermal barrier coated SI engine by adding argon inert gas to intake mixture.

Science.gov (United States)

Karthikeya Sharma, T

2015-11-01

Dilution of the intake air of the SI engine with the inert gases is one of the emission control techniques like exhaust gas recirculation, water injection into combustion chamber and cyclic variability, without scarifying power output and/or thermal efficiency (TE). This paper investigates the effects of using argon (Ar) gas to mitigate the spark ignition engine intake air to enhance the performance and cut down the emissions mainly nitrogen oxides. The input variables of this study include the compression ratio, stroke length, and engine speed and argon concentration. Output parameters like TE, volumetric efficiency, heat release rates, brake power, exhaust gas temperature and emissions of NOx, CO2 and CO were studied in a thermal barrier coated SI engine, under variable argon concentrations. Results of this study showed that the inclusion of Argon to the input air of the thermal barrier coated SI engine has significantly improved the emission characteristics and engine's performance within the range studied.

Wave Engine Topping Cycle Assessment

Science.gov (United States)

Welch, Gerard E.

1996-01-01

The performance benefits derived by topping a gas turbine engine with a wave engine are assessed. The wave engine is a wave rotor that produces shaft power by exploiting gas dynamic energy exchange and flow turning. The wave engine is added to the baseline turboshaft engine while keeping high-pressure-turbine inlet conditions, compressor pressure ratio, engine mass flow rate, and cooling flow fractions fixed. Related work has focused on topping with pressure-exchangers (i.e., wave rotors that provide pressure gain with zero net shaft power output); however, more energy can be added to a wave-engine-topped cycle leading to greater engine specific-power-enhancement The energy addition occurs at a lower pressure in the wave-engine-topped cycle; thus the specific-fuel-consumption-enhancement effected by ideal wave engine topping is slightly lower than that effected by ideal pressure-exchanger topping. At a component level, however, flow turning affords the wave engine a degree-of-freedom relative to the pressure-exchanger that enables a more efficient match with the baseline engine. In some cases, therefore, the SFC-enhancement by wave engine topping is greater than that by pressure-exchanger topping. An ideal wave-rotor-characteristic is used to identify key wave engine design parameters and to contrast the wave engine and pressure-exchanger topping approaches. An aerodynamic design procedure is described in which wave engine design-point performance levels are computed using a one-dimensional wave rotor model. Wave engines using various wave cycles are considered including two-port cycles with on-rotor combustion (valved-combustors) and reverse-flow and through-flow four-port cycles with heat addition in conventional burners. A through-flow wave cycle design with symmetric blading is used to assess engine performance benefits. The wave-engine-topped turboshaft engine produces 16% more power than does a pressure-exchanger-topped engine under the specified topping

Engineering photonic and plasmonic light emission enhancement

Science.gov (United States)

Lawrence, Nathaniel

Semiconductor photonic devices are a rapidly maturing technology which currently occupy multi-billion dollar markets in the areas of LED lighting and optical data communication. LEDs currently demonstrate the highest luminous efficiency of any light source for general lighting. Long-haul optical data communication currently forms the backbone of the global communication network. Proper design of light management is required for photonic devices, which can increase the overall efficiency or add new device functionality. In this thesis, novel methods for the control of light propagation and confinement are developed for the use in integrated photonic devices. The first part of this work focuses on the engineering of field confinement within deep subwavelength plasmonic resonators for the enhancement of light-matter interaction. In this section, plasmonic ring nanocavities are shown to form gap plasmon modes confined to the dielectric region between two metal layers. The scattering properties, near-field enhancement and photonic density of states of nanocavity devices are studied using analytic theory and 3D finite difference time domain simulations. Plasmonic ring nanocavities are fabricated and characterized using photoluminescence intensity and decay rate measurements. A 25 times increase in the radiative decay rate of Er:Si02 is demonstrated in nanocavities where light is confined to volumes as small as 0.01( ln )3. The potential to achieve lasing, due to the enhancement of stimulated emission rate in ring nanocavities, is studied as a route to Si-compatible plasmon-enhanced nanolasers. The second part of this work focuses on the manipulation of light generated in planar semiconductor devices using arrays of dielectric nanopillars. In particular, aperiodic arrays of nanopillars are engineered for omnidirectional light extraction enhancement. Arrays of Er:SiNx, nanopillars are fabricated and a ten times increase in light extraction is experimentally demonstrated

Enhancement of Global Communication Skill at the School of Engineering

Science.gov (United States)

Morimura, Kumiko

Globalization is one of the most important challenges for universities. Especially for the School of Engineering, it is crucial to foster researchers or engineers with broader perspective. International communication competency is essential for them in order to deal with other professionals from overseas. Center for Innovation in Engineering Education established in the School of Engineering at the University of Tokyo in 2005 started two programs for graduate and undergraduate students to enhance their international communication competency and to increase international competitiveness. ‘English for Scientists and Engineers A, B’ are for the graduate students to learn how to write papers in English and how to make good presentations. Special English Lessons are for the undergraduate students to have a chance to practice English conversation or prepare for TOEFL test. In this paper, the authors discuss the details of the programs, their purpose and the future tasks.

A High-Performance Parallel FDTD Method Enhanced by Using SSE Instruction Set

Directory of Open Access Journals (Sweden)

Dau-Chyrh Chang

2012-01-01

Full Text Available We introduce a hardware acceleration technique for the parallel finite difference time domain (FDTD method using the SSE (streaming (single instruction multiple data SIMD extensions instruction set. The implementation of SSE instruction set to parallel FDTD method has achieved the significant improvement on the simulation performance. The benchmarks of the SSE acceleration on both the multi-CPU workstation and computer cluster have demonstrated the advantages of (vector arithmetic logic unit VALU acceleration over GPU acceleration. Several engineering applications are employed to demonstrate the performance of parallel FDTD method enhanced by SSE instruction set.

Hydrogen engine performance analysis. First annual report

Energy Technology Data Exchange (ETDEWEB)

Adt, Jr., R. R.; Swain, M. R.; Pappas, J. M.

1978-08-01

Many problems associated with the design and development of hydrogen-air breathing internal combustion engines for automotive applications have been identified by various domestic and foreign researchers. This project addresses the problems identified in the literature, seeks to evaluate potential solutions to these problems, and will obtain and document a design data-base convering the performance, operational and emissions characteristics essential for making rational decisions regarding the selection and design of prototype hydrogen-fueled, airbreathing engines suitable for manufacture for general automotive use. Information is included on the operation, safety, emission, and cost characteristics of hydrogen engines, the selection of a test engine and testing facilities, and experimental results. Baseline data for throttled and unthrottled, carburetted, hydrogen engine configurations with and without exhaust gas recirculation and water injection are presented. In addition to basic data gathering concerning performance and emissions, the test program conducted was formulated to address in detail the two major problems that must be overcome if hydrogen-fueled engines are to become viable: flashback and comparatively high NO/sub x/ emissions at high loads. In addition, the results of other hydrogen engine investigators were adjusted, using accepted methods, in order to make comparisons with the results of the present study. The comparisons revealed no major conflicts. In fact, with a few exceptions, there was found to be very good agreement between the results of the various studies.

Rotary engine performance limits predicted by a zero-dimensional model

Science.gov (United States)

Bartrand, Timothy A.; Willis, Edward A.

1992-01-01

A parametric study was performed to determine the performance limits of a rotary combustion engine. This study shows how well increasing the combustion rate, insulating, and turbocharging increase brake power and decrease fuel consumption. Several generalizations can be made from the findings. First, it was shown that the fastest combustion rate is not necessarily the best combustion rate. Second, several engine insulation schemes were employed for a turbocharged engine. Performance improved only for a highly insulated engine. Finally, the variability of turbocompounding and the influence of exhaust port shape were calculated. Rotary engines performance was predicted by an improved zero-dimensional computer model based on a model developed at the Massachusetts Institute of Technology in the 1980's. Independent variables in the study include turbocharging, manifold pressures, wall thermal properties, leakage area, and exhaust port geometry. Additions to the computer programs since its results were last published include turbocharging, manifold modeling, and improved friction power loss calculation. The baseline engine for this study is a single rotor 650 cc direct-injection stratified-charge engine with aluminum housings and a stainless steel rotor. Engine maps are provided for the baseline and turbocharged versions of the engine.

Research Skills Enhancement in Future Mechanical Engineers

Directory of Open Access Journals (Sweden)

Jorge Lino Alves

2011-04-01

Full Text Available Nowadays, the Web is a common tool for students searching information about the subjects taught in the different university courses. Although this is a good tool for the first rapid knowledge, a deeper study is usually demanded.

After many years of teaching a course about ceramic and composite materials in the Integrated Master in Mechanical Engineering of Faculty of Engineering of University of Porto, Portugal, the authors used the Bologna reformulation of the mechanical engineering course to introduce new teaching methodologies based on a project based learning methodology.

One of the main innovations is a practical work that comprises the study of a recent ceramic scientific paper, using all the actual available tools, elaboration of a scientific report, work presentation and participation in a debate.

With this innovative teaching method the enrolment of the students was enhanced with a better knowledge about the ceramics subject and the skills related with the CDIO competences.

This paper presents the reasons for this implementation and explains the teaching methodology adopted as well as the changes obtained in the students’ final results.

Lean mixture engine testing and evaluation program. [for automobile engine pollution and fuel performances

Science.gov (United States)

Dowdy, M. W.; Hoehn, F. W.; Griffin, D. C.

1975-01-01

Experimental results for fuel consumption and emissions are presented for a 350 CID (5.7 liter) Chevrolet V-8 engine modified for lean operation with gasoline. The lean burn engine achieved peak thermal efficiency at an equivalence ratio of 0.75 and a spark advance of 60 deg BTDC. At this condition the lean burn engine demonstrated a 10% reduction in brake specific fuel consumption compared with the stock engine; however, NOx and hydrocarbon emissions were higher. With the use of spark retard and/or slightly lower equivalence ratios, the NOx emissions performance of the stock engine was matched while showing a 6% reduction in brake specific fuel consumption. Hydrocarbon emissions exceeded the stock values in all cases. Diagnostic data indicate that lean performance in the engine configuration tested is limited by ignition delay, cycle-to-cycle pressure variations, and cylinder-to-cylinder distribution.

Miniature free-piston homogeneous charge compression ignition engine-compressor concept - Part I: performance estimation and design considerations unique to small dimensions

Energy Technology Data Exchange (ETDEWEB)

Aichlmayr, H.T.; Kittelson, D.B.; Zachariah, M.R. [The University of Minnesota, Minneapolis (United States). Departments of Mechanical Engineering and Chemistry

2002-10-01

Research and development activities pertaining to the development of a 10 W, homogeneous charge compression ignition free-piston engine-compressor are presented. Emphasis is place upon the miniature engine concept and design rationale. Also, a crankcase-scavenged, two-stroke engine performance estimation method (slider-crank piston motion) is developed and used to explore the influence of engine operating conditions and geometric parameters on power density and establish plausible design conditions. The minimization of small-scale effects such as enhanced heat transfer, is also explored. (author)

Engine Performance Test of the 1975 Chrysler - Nissan Model CN633 Diesel Engine

Science.gov (United States)

1975-09-01

An engine test of the Chrysler-Nissan Model CN633 diesel engine was performed to determine its steady-state fuel consumption and emissions (HC, CO, NOx) maps. The data acquired are summarized in this report.

Performance and emission of CI engine fuelled with camelina sativa oil

International Nuclear Information System (INIS)

Kruczyński, Stanisław W.

2013-01-01

Highlights: ► Camelina sativa as a potential source of alternative fuel. ► Neat camelina sativa oil as a fuel for CI engine. ► The engine performance and emissions of CI engine fuelled with neat camelina sativa oil. ► Comparison of rate of heat release for camelina sativa oil and diesel oil. - Abstract: The paper describes the results of the tests of CI Perkins 1104C-44 engine fuelled with camelina sativa oil. The engine was not especially calibrated for fuelling with the vegetable fuel. During the test the engine performance and emissions were analysed. For comparison the same speed characteristic was examined for standard fuelling of the engine with diesel oil. In order to understand the engine performance and emission the mass fraction burnt and the rate of heat release was calculated and compared for the same energy provided to the engine cylinder with the injected fuels. The results show that there is possible to receive relatively good engine performance for fuelling the engine with camelina sativa oil but there is a need to change the calibration parameters of the engine fuel system when the engine is fuelled with this fuel.

Enhancing vehicle’s engine warm up using integrated mechanical approach

Science.gov (United States)

Ibrahim, T. M.; Syahir, A. Z.; Zulkifli, N. W. M.; Masjuki, H. H.; Osman, A.

2017-06-01

Transportation sector covers a large portion of the total energy consumption shares and is highly associated to global warming. Growing concern over the harmful gases being emitted from vehicles and their environmental implications has urged the need for pollutant reduction through more efficient engines. Good engine thermal management especially during cold-start warm up phase has been proven to enhance the engine efficiency in terms of fuel economy and greenhouse emissions specifically. In this study, the viability engine split cooling system was tested in two separate test. The parameters of interest include coolant and transmission temperature as these both parameters indicate the internal engine condition and highly associated with engine efficiency. In the first idle test, coolant temperature within the modified cooling configuration reached the optimum coolant temperature of 60 °C about 41.28% faster when compared to baseline configuration. The modified configuration also heat up the transmission oil around 4 times faster. In the second NEDC test which simulates the real time driving condition, the coolant of the modified vehicle reached the optimum temperature around 28.26% compared to the baseline.

Performance and combustion characteristics of direct-injection stratified-charge rotary engines

Science.gov (United States)

Nguyen, Hung Lee

1987-01-01

Computer simulations of the direct-injection stratified-charge (DISC) Wankel engine have been used to calculate heat release rates and performance and efficiency characteristics of the 1007R engine. Engine pressure data have been used in a heat release analysis to study the effects of heat transfer, leakage, and crevice flows. Predicted engine performance data are compared with experimental test data over a range of engine speeds and loads. An examination of methods to improve the performance of the Wankel engine with faster combustion, reduced leakage, higher compression ratio, and turbocharging is presented.

Predicted performance of an integrated modular engine system

Science.gov (United States)

Binder, Michael; Felder, James L.

1993-01-01

Space vehicle propulsion systems are traditionally comprised of a cluster of discrete engines, each with its own set of turbopumps, valves, and a thrust chamber. The Integrated Modular Engine (IME) concept proposes a vehicle propulsion system comprised of multiple turbopumps, valves, and thrust chambers which are all interconnected. The IME concept has potential advantages in fault-tolerance, weight, and operational efficiency compared with the traditional clustered engine configuration. The purpose of this study is to examine the steady-state performance of an IME system with various components removed to simulate fault conditions. An IME configuration for a hydrogen/oxygen expander cycle propulsion system with four sets of turbopumps and eight thrust chambers has been modeled using the Rocket Engine Transient Simulator (ROCETS) program. The nominal steady-state performance is simulated, as well as turbopump thrust chamber and duct failures. The impact of component failures on system performance is discussed in the context of the system's fault tolerant capabilities.

The Little Engines That Could: Modeling the Performance of World Wide Web Search Engines

OpenAIRE

Eric T. Bradlow; David C. Schmittlein

2000-01-01

This research examines the ability of six popular Web search engines, individually and collectively, to locate Web pages containing common marketing/management phrases. We propose and validate a model for search engine performance that is able to represent key patterns of coverage and overlap among the engines. The model enables us to estimate the typical additional benefit of using multiple search engines, depending on the particular set of engines being considered. It also provides an estim...

Energetic optimization of the performances of a hot air engine for micro-CHP systems working with a Joule or an Ericsson cycle

International Nuclear Information System (INIS)

Creyx, M.; Delacourt, E.; Morin, C.; Desmet, B.; Peultier, P.

2013-01-01

The micro combined heat and electrical power systems (micro-CHP) with hot air engines are well adapted for solid biomass upgrading, in particular, the Ericsson engines working with an open cycle and an external combustion. This paper presents a model of an Ericsson engine with a compression and an expansion cylinder which allows a thermodynamic optimization of the engine performances in a global approach. A sensitive analysis on the influent parameters is carried out in order to determine the optimal working conditions of the engine: temperature and pressure range, expansion cycle shape with a late intake valve closing or an early exhaust valve closing, heat transfers through the wall of the cylinders. This study, focused on thermodynamic aspects, is a first step in the design of an Ericsson engine. -- Highlights: ► A model of Ericsson engine working with a Joule or Ericsson cycle is presented. ► Influent factors on the engine performances are investigated. ► The heat exchanges in the cylinder wall must be avoided to improve the performances. ► Closing the intake valve late and the exhaust valve early enhances the performances. ► Efficiency, indicated mean pressure, specific work are thermodynamically optimized.

Device Engineering Towards Improved Tin Sulfide Solar Cell Performance and Performance Reproducibility

Energy Technology Data Exchange (ETDEWEB)

Steinmann, Vera; Chakraborty, Rupak; Rekemeyer, Paul; Siol, Sebastian; Martinot, Loic; Polizzotti, Alex; Yang, Chuanxi; Hartman, Katy; Gradecak, Silvija; Zakutayev, Andriy; Gordon, Roy G.; Buonassisi, Tonio

2016-11-21

As novel absorber materials are developed and screened for their photovoltaic (PV) properties, the challenge remains to rapidly test promising candidates in high-performing PV devices. There is a need to engineer new compatible device architectures, including the development of novel transparent conductive oxides and buffer layers. Here, we consider the two approaches of a substrate-style and a superstrate-style device architecture for novel thin-film solar cells. We use tin sulfide as a test absorber material. Upon device engineering, we demonstrate new approaches to improve device performance and performance reproducibility.

An experimental investigation of performance-emission trade off characteristics of a CI engine using hydrogen as dual fuel

International Nuclear Information System (INIS)

Deb, Madhujit; Paul, Abhishek; Debroy, Durbadal; Sastry, G.R.K.; Panua, Raj Sekhar; Bose, P.K.

2015-01-01

The investigation carried out in this research work concerns the effect of the addition of H 2 on performance and emission characteristics of a single cylinder, 4-stroke diesel engine. The tests were performed using diesel as a pilot fuel, with hydrogen addition at varying load condition using a Timed Manifold Injection (TMI) system has been developed using ECU (electronic control unit) with varying injection strategy to deliver hydrogen on to the intake manifold. The results showed a significant increase in BTE with appreciable decrease in BSEC of the engine when compared to conventional diesel-fueled operation. The emission of CO 2 and NOx was found to increase with enhancement of H 2 addition. The emission of UHC was found to be very high at low load conditions, but it enhanced as the load increased for all hydrogen injection while Soot emissions decreased. Thus, this paper provided a potential to investigate the effect of the addition of H 2 on the performance and emission characteristics of a diesel engine and how to get a best ratio of H 2 addition. The tradeoff study also consolidated the verity that Diesel–H 2 dual fuel operation was instrumental in resolving the high performance – low emission paradox. - Highlights: • Pure diesel and diesel–H 2 blends are tested. • Diesel–H 2 blends produced higher brake thermal efficiency than pure diesel in all part loads. • Diesel–H 2 blends reduced the energy consumption of the engine. • Diesel–H 2 blends simultaneously reduced Soot to some extent but increases N Ox and hydrocarbon emissions. • The performance-emission trade-off paradox has been studied using pure diesel and diesel–H 2 blends

Performance and emission characteristics of the thermal barrier coated SI engine by adding argon inert gas to intake mixture

Directory of Open Access Journals (Sweden)

T. Karthikeya Sharma

2015-11-01

Full Text Available Dilution of the intake air of the SI engine with the inert gases is one of the emission control techniques like exhaust gas recirculation, water injection into combustion chamber and cyclic variability, without scarifying power output and/or thermal efficiency (TE. This paper investigates the effects of using argon (Ar gas to mitigate the spark ignition engine intake air to enhance the performance and cut down the emissions mainly nitrogen oxides. The input variables of this study include the compression ratio, stroke length, and engine speed and argon concentration. Output parameters like TE, volumetric efficiency, heat release rates, brake power, exhaust gas temperature and emissions of NOx, CO2 and CO were studied in a thermal barrier coated SI engine, under variable argon concentrations. Results of this study showed that the inclusion of Argon to the input air of the thermal barrier coated SI engine has significantly improved the emission characteristics and engine’s performance within the range studied.

Impact of alternative fuels on the operational and environmental performance of a small turbofan engine

International Nuclear Information System (INIS)

Gaspar, R.M.P.; Sousa, J.M.M.

2016-01-01

Highlights: • A wide range of alternative fuels is studied in a small two-spool turbofan engine. • Impact of fuel properties on flame temperature and droplet evaporation considered. • Performance and pollutant emissions at different operating conditions are analyzed. • Use of alternative fuels generally leads to an improved performance of the engine. • Mostly reductions in soot emissions, but also cuts in NO_x and CO, are obtained. - Abstract: A wide range of alternative jet fuels is studied in this work for use in a small two-spool turbofan engine. These embrace the five production pathways currently approved by the American Society for Testing and Materials. Both neat products and blends (within certified limits) have been considered. The present analysis is based on a 0-D thermodynamic modeling of the aero-engine for off-design and transient simulations. In addition, the selected approach incorporates fuel effects on combustion and the impact of fuel properties on the flame temperature, as well as on the droplet evaporation rate. Predicted performance and pollutant emission outputs for the alternative fuels are presented at different operating conditions, namely: take-off, top of climb, cruise, low power and ground idle. The results are discussed and comprehensively compared with data available in the literature. It was concluded that the combustion of alternative fuels generally leads to enhancements in engine performance with respect to the use of conventional kerosene. Reductions in pollutant emissions occur mostly in soot, but also in nitrogen oxides and carbon monoxide, depending on the fuel and operating conditions. In contrast, increased emissions of unburned hydrocarbons are generally observed. Concerns about the aero-engine dynamic response are raised only in very few cases, involving the use of neat products.

Thermochemical surface engineering of steels

DEFF Research Database (Denmark)

Thermochemical Surface Engineering of Steels provides a comprehensive scientific overview of the principles and different techniques involved in thermochemical surface engineering, including thermodynamics, kinetics principles, process technologies and techniques for enhanced performance of steels...

Performance and emissions analysis on using acetone–gasoline fuel blends in spark-ignition engine

Directory of Open Access Journals (Sweden)

Ashraf Elfasakhany

2016-09-01

Full Text Available In this study, new blended fuels were formed by adding 3–10 vol. % of acetone into a regular gasoline. According to the best of the author's knowledge, it is the first time that the influence of acetone blends has been studied in a gasoline-fueled engine. The blended fuels were tested for their energy efficiencies and pollutant emissions using SI (spark-ignition engine with single-cylinder and 4-stroke. Experimental results showed that the AC3 (3 vol.% acetone + 97 vol.% gasoline blended fuel has an advantage over the neat gasoline in exhaust gases temperature, in-cylinder pressure, brake power, torque and volumetric efficiency by about 0.8%, 2.3%, 1.3%, 0.45% and 0.9%, respectively. As the acetone content increases in the blends, as the engine performance improved where the best performance obtained in this study at the blended fuel of AC10. In particular, exhaust gases temperature, in-cylinder pressure, brake power, torque and volumetric efficiency increase by about 5%, 10.5%, 5.2%, 2.1% and 3.2%, respectively, compared to neat gasoline. In addition, the use of acetone with gasoline fuel reduces exhaust emissions averagely by about 43% for carbon monoxide, 32% for carbon dioxide and 33% for the unburnt hydrocarbons. The enhanced engine performance and pollutant emissions are attributed to the higher oxygen content, slight leaning effect, lower knock tendency and high flame speeds of acetone, compared to the neat gasoline. Finally the mechanism of acetone combustion in gasoline-fueled engines is proposed in this work; two main pathways for acetone combustion are highlighted; furthermore, the CO, CO2 and UHC (unburnt hydrocarbons mechanisms of formation and oxidation are acknowledged. Such acetone mechanism is employed for further understanding acetone combustion in spark-ignition engines.

In-cylinder tumble flows and performance of a motorcycle engine with circular and elliptic intake ports

Science.gov (United States)

Huang, R. F.; Lin, K. H.; Yeh, C.-N.; Lan, J.

2009-01-01

The temporal and spatial evolution processes of the flows in the cylinder of a four-valve, four-stroke, single cylinder, reciprocating motorcycle engine installed with the elliptic and circular intake ports were experimentally studied by using the particle image velocimetry (PIV). The engine was modified to fit the requirements of PIV measurement. The velocity fields measured by the PIV were analyzed and quantitatively presented as the tumble ratio and turbulence intensity. In the symmetry plane, both the circular and elliptic intake ports could initiate a vortex around the central region during the intake stroke. During the compression stroke, the central vortex created in the cylinder of the engine with the circular intake port disappeared, while that in the engine cylinder with the elliptic intake port further developed into the tumble motion. In the offset plane, weak vortical structures were initiated by the bluff-body effect of the intake valves during the intake stroke. The vortical structures induced by the elliptic intake port were more coherent than those generated by the circular intake port; besides, this feature extends to the compression stroke. The cycle-averaged tumble ratio and the turbulence intensity of the engine with the elliptic intake port were dramatically larger than those of the engine with the circular intake port. The measured engine performance was improved a lot by installing the elliptic intake port. The correlation between the flow features and the enhancement of the engine performance were argued and discussed.

Dynamic Performance of High Bypass Ratio Turbine Engines With Water Ingestion

Science.gov (United States)

Murthy, S. N. B.

1996-01-01

The research on dynamic performance of high bypass turbofan engines includes studies on inlets, turbomachinery and the total engine system operating with air-water mixture; the water may be in vapor, droplet, or film form, and their combinations. Prediction codes (WISGS, WINCOF, WINCOF-1, WINCLR, and Transient Engine Performance Code) for performance changes, as well as changes in blade-casing clearance, have been established and demonstrated in application to actual, generic engines. In view of the continuous changes in water distribution in turbomachinery, the performance of both components and the total engine system must be determined in a time-dependent mode; hence, the determination of clearance changes also requires a time-dependent approach. In general, the performance and clearances changes cannot be scaled either with respect to operating or ingestion conditions. Removal of water prior to phase change is the most effective means of avoiding ingestion effects. Sufficient background has been established to perform definitive, full scale tests on a set of components and a complete engine to establish engine control and operability with various air-water vapor-water mixtures.

Host and Pathway Engineering for Enhanced Lycopene Biosynthesis in Yarrowia lipolytica

Directory of Open Access Journals (Sweden)

Cory Schwartz

2017-11-01

Full Text Available Carotenoids are a class of molecules with commercial value as food and feed additives with nutraceutical properties. Shifting carotenoid synthesis from petrochemical-based precursors to bioproduction from sugars and other biorenewable carbon sources promises to improve process sustainability and economics. In this work, we engineered the oleaginous yeast Yarrowia lipolytica to produce the carotenoid lycopene. To enhance lycopene production, we tested a series of strategies to modify host cell physiology and metabolism, the most successful of which were mevalonate pathway overexpression and alleviating auxotrophies previously engineered into the PO1f strain of Y. lipolytica. The beneficial engineering strategies were combined into a single strain, which was then cultured in a 1-L bioreactor to produce 21.1 mg/g DCW. The optimized strain overexpressed a total of eight genes including two copies of HMG1, two copies of CrtI, and single copies of MVD1, EGR8, CrtB, and CrtE. Recovering leucine and uracil biosynthetic capacity also produced significant enhancement in lycopene titer. The successful engineering strategies characterized in this work represent a significant increase in understanding carotenoid biosynthesis in Y. lipolytica, not only increasing lycopene titer but also informing future studies on carotenoid biosynthesis.

Performance of a supercharged direct-injection stratified-charge rotary combustion engine

Science.gov (United States)

Bartrand, Timothy A.; Willis, Edward A.

1990-01-01

A zero-dimensional thermodynamic performance computer model for direct-injection stratified-charge rotary combustion engines was modified and run for a single rotor supercharged engine. Operating conditions for the computer runs were a single boost pressure and a matrix of speeds, loads and engine materials. A representative engine map is presented showing the predicted range of efficient operation. After discussion of the engine map, a number of engine features are analyzed individually. These features are: heat transfer and the influence insulating materials have on engine performance and exhaust energy; intake manifold pressure oscillations and interactions with the combustion chamber; and performance losses and seal friction. Finally, code running times and convergence data are presented.

Enhancing LAN performance

CERN Document Server

Held, Gilbert

2004-01-01

Enhancing LAN Performance, Fourth Edition explains how to connect geographically separated LANs with appropriate bandwidth, the issues to consider when weighing the use of multiport or dualport devices, how to estimate traffic for new networks, the effects of configuration changes on the performance of Ethernet and Token Ring networks, the design of switch-based networks that prevent traffic bottlenecks, and other critical topics. It provides the tools to address these issues in relation to specific network requirements. This volume develops mathematical models of various LAN performance issue

Engineering and Optimization of Silicon-Iron-Manganese Nanoalloy Electrode for Enhanced Lithium-Ion Battery

Science.gov (United States)

Alaboina, Pankaj K.; Cho, Jong-Soo; Cho, Sung-Jin

2017-10-01

The electrochemical performance of a battery is considered to be primarily dependent on the electrode material. However, engineering and optimization of electrodes also play a crucial role, and the same electrode material can be designed to offer significantly improved batteries. In this work, Si-Fe-Mn nanomaterial alloy (Si/alloy) and graphite composite electrodes were densified at different calendering conditions of 3, 5, and 8 tons, and its influence on electrode porosity, electrolyte wettability, and long-term cycling was investigated. The active material loading was maintained very high ( 2 mg cm-2) to implement electrode engineering close to commercial loading scales. The densification was optimized to balance between the electrode thickness and wettability to enable the best electrochemical properties of the Si/alloy anodes. In this case, engineering and optimizing the Si/alloy composite electrodes to 3 ton calendering (electrode densification from 0.39 to 0.48 g cm-3) showed enhanced cycling stability with a high capacity retention of 100% over 100 cycles. [Figure not available: see fulltext.

Impact of gate engineering in enhancement mode n++GaN/InAlN/AlN/GaN HEMTs

Science.gov (United States)

Adak, Sarosij; Swain, Sanjit Kumar; Rahaman, Hafizur; Sarkar, Chandan Kumar

2016-12-01

This paper illustrate the effect of gate material engineering on the performance of enhancement mode n++GaN/InAlN/AlN/GaN high electron mobility transistors (HEMTs). A comparative analysis of key device parameters is discussed for the Triple Material Gate (TMG), Dual Material Gate (DMG) and the Single Material Gate (SMG) structure HEMTs by considering the same device dimensions. The simulation results shows that an significant improvement is noticed in the key analysis parameters such as drain current (Id), transconductance (gm), cut off frequency (fT), RF current gain, maximum cut off frequency (fmax) and RF power gain of the gate material engineered devices with respect to SMG normally off n++GaN/InAlN/AlN/GaN HEMTs. This improvement is due to the existence of the perceivable step in the surface potential along the channel which successfully screens the drain potential variation in the source side of the channel for the gate engineering devices. The analysis suggested that the proposed TMG and DMG engineered structure enhancement mode n++GaN/InAlN/AlN/GaN HEMTs can be considered as a potential device for future high speed, microwave and digital application.

Enhancing the engineering properties of expansive soil using bagasse ash

Science.gov (United States)

Silmi Surjandari, Niken; Djarwanti, Noegroho; Umri Ukoi, Nafisah

2017-11-01

This paper deals with stabilization of expansive soil on a laboratory experimental basis. The aim of the research was to evaluate the enhancement of the engineering properties of expansive soil using bagasse ash. The soil is treated with bagasse ash by weight (0, 5, 10, 15, and 20%) based on dry mass. The performance of bagasse ash stabilized soil was evaluated using physical and strength performance tests, namely the plasticity index, standard Proctor compaction, and percentage swelling. An X-ray diffraction (XRD) test was conducted to evaluate the clay mineral, whereas an X-ray fluorescence (XRF) was to the chemical composition of bagasse ash. From the results, it was observed that the basic tests carried out proved some soil properties after the addition of bagasse ash. Furthermore, the plasticity index decreased from 53.18 to 47.70%. The maximum dry density of the specimen increased from 1.13 to 1.24 gr/cm3. The percentage swelling decreased from 5.48 to 3.29%. The outcomes of these tests demonstrate that stabilization of expansive soils using bagasse ash can improve the strength.

Systems engineering approach towards performance monitoring of emergency diesel generator

International Nuclear Information System (INIS)

Nurhayati Ramli; Lee, Y.K.

2013-01-01

Full-text: Systems engineering is an interdisciplinary approach and means to enable the realization of successful systems. In this study, systems engineering approach towards the performance monitoring of Emergency Diesel Generator (EDG) is presented. Performance monitoring is part and parcel of predictive maintenance where the systems and components conditions can be detected before they result into failures. In an effort to identify the proposal for addressing performance monitoring, the EDG boundary has been defined. Based on the Probabilistic Safety Analysis (PSA) results and industry operating experiences, the most critical component is identified. This paper proposed a systems engineering concept development framework towards EDG performance monitoring. The expected output of this study is that the EDG reliability can be improved by the performance monitoring alternatives through the systems engineering concept development effort. (author)

Interface Engineering and Gate Dielectric Engineering for High Performance Ge MOSFETs

Directory of Open Access Journals (Sweden)

Jiabao Sun

2015-01-01

Full Text Available In recent years, germanium has attracted intensive interests for its promising applications in the microelectronics industry. However, to achieve high performance Ge channel devices, several critical issues still have to be addressed. Amongst them, a high quality gate stack, that is, a low defect interface layer and a dielectric layer, is of crucial importance. In this work, we first review the existing methods of interface engineering and gate dielectric engineering and then in more detail we discuss and compare three promising approaches (i.e., plasma postoxidation, high pressure oxidation, and ozone postoxidation. It has been confirmed that these approaches all can significantly improve the overall performance of the metal-oxide-semiconductor field effect transistor (MOSFET device.

Enhanced Core Noise Modeling for Turbofan Engines

Science.gov (United States)

Stone, James R.; Krejsa, Eugene A.; Clark, Bruce J.

2011-01-01

This report describes work performed by MTC Technologies (MTCT) for NASA Glenn Research Center (GRC) under Contract NAS3-00178, Task Order No. 15. MTCT previously developed a first-generation empirical model that correlates the core/combustion noise of four GE engines, the CF6, CF34, CFM56, and GE90 for General Electric (GE) under Contract No. 200-1X-14W53048, in support of GRC Contract NAS3-01135. MTCT has demonstrated in earlier noise modeling efforts that the improvement of predictive modeling is greatly enhanced by an iterative approach, so in support of NASA's Quiet Aircraft Technology Project, GRC sponsored this effort to improve the model. Since the noise data available for correlation are total engine noise spectra, it is total engine noise that must be predicted. Since the scope of this effort was not sufficient to explore fan and turbine noise, the most meaningful comparisons must be restricted to frequencies below the blade passage frequency. Below the blade passage frequency and at relatively high power settings jet noise is expected to be the dominant source, and comparisons are shown that demonstrate the accuracy of the jet noise model recently developed by MTCT for NASA under Contract NAS3-00178, Task Order No. 10. At lower power settings the core noise became most apparent, and these data corrected for the contribution of jet noise were then used to establish the characteristics of core noise. There is clearly more than one spectral range where core noise is evident, so the spectral approach developed by von Glahn and Krejsa in 1982 wherein four spectral regions overlap, was used in the GE effort. Further analysis indicates that the two higher frequency components, which are often somewhat masked by turbomachinery noise, can be treated as one component, and it is on that basis that the current model is formulated. The frequency scaling relationships are improved and are now based on combustor and core nozzle geometries. In conjunction with the Task

Enhanced Component Performance Study: Emergency Diesel Generators 1998-2014

International Nuclear Information System (INIS)

Schroeder, John Alton

2015-01-01

This report presents an enhanced performance evaluation of emergency diesel generators (EDGs) at U.S. commercial nuclear power plants. This report evaluates component performance over time using (1) Institute of Nuclear Power Operations (INPO) Consolidated Events Database (ICES) data from 1998 through 2014 and (2) maintenance unavailability (UA) performance data from Mitigating Systems Performance Index (MSPI) Basis Document data from 2002 through 2014. The objective is to show estimates of current failure probabilities and rates related to EDGs, trend these data on an annual basis, determine if the current data are consistent with the probability distributions currently recommended for use in NRC probabilistic risk assessments, show how the reliability data differ for different EDG manufacturers and for EDGs with different ratings; and summarize the subcomponents, causes, detection methods, and recovery associated with each EDG failure mode. Engineering analyses were performed with respect to time period and failure mode without regard to the actual number of EDGs at each plant. The factors analyzed are: sub-component, failure cause, detection method, recovery, manufacturer, and EDG rating. Six trends with varying degrees of statistical significance were identified in the data.

Engineering Metallic Nanoparticles for Enhancing and Probing Catalytic Reactions.

Science.gov (United States)

Collins, Gillian; Holmes, Justin D

2016-07-01

Recent developments in tailoring the structural and chemical properties of colloidal metal nanoparticles (NPs) have led to significant enhancements in catalyst performance. Controllable colloidal synthesis has also allowed tailor-made NPs to serve as mechanistic probes for catalytic processes. The innovative use of colloidal NPs to gain fundamental insights into catalytic function will be highlighted across a variety of catalytic and electrocatalytic applications. The engineering of future heterogenous catalysts is also moving beyond size, shape and composition considerations. Advancements in understanding structure-property relationships have enabled incorporation of complex features such as tuning surface strain to influence the behavior of catalytic NPs. Exploiting plasmonic properties and altering colloidal surface chemistry through functionalization are also emerging as important areas for rational design of catalytic NPs. This news article will highlight the key developments and challenges to the future design of catalytic NPs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Performance, combustion, and emission characteristics of a diesel engine fueled by biodiesel-diesel mixtures with multi-walled carbon nanotubes additives

International Nuclear Information System (INIS)

El-Seesy, Ahmed I.; Abdel-Rahman, Ali K.; Bady, Mahmoud; Ookawara, S.

2017-01-01

Highlights: • Considerable improvements in the combustion of JB20D50MWCNTs compared to pure JB20D. • p_m_a_x, dp/dθ_m_a_x and dQg/dθ_m_a_x increased by 7%, 4% and 4%, respectively. • Brake specific fuel consumption decreased by 15%. • NO_x, CO, and UHC reduced by 35%, 50%, and 60%, respectively. • Significant enhancement in all engine performance was achieved at a concentration of 40 mg/l. - Abstract: In this work, the effects of adding Multi-Walled Carbon nanotubes (MWCNTs) to Jojoba methyl ester-diesel blended fuel (JB20D) on performance, combustion and emissions characteristics of a compression-ignition engine were experimentally investigated. The JB20D with 10, 20, 30, 40 and 50 mg/l of MWCNTs were examined at different engine loads and speeds. Compared to pure diesel, the use of JB20D without MWCNTs caused a slight decrease in the engine performance and an increase in the engine emissions at most examined conditions. The MWCNTs–B20D blended fuel attained a maximum increase of 16% in the brake thermal efficiency and a decrease of 15% in the brake specific fuel consumption at the dose level of 50 mg/l compared to JB20D. The MWCNTs-JB20D blended fuel also brought about an enhancement in combustion characteristics where the peak cylinder pressure, the maximum rate of pressure rise and the peak heat release rate were increased by 7%, 4%, and 4%, respectively, at the same dose level. According to the measured emissions, a significant reduction of engine emissions was achieved at the dose level of 20 mg/l, where NO_x, CO, and UHC were reduced by 35%, 50%, and 60%, respectively. According to the obtained results, the recommended concentration of MWCNTs in JB20D was concluded to be 40 mg/l, which could give significant improvements in overall the parameters of engine performance and emissions with a good balance between them.

Innovative Assessment Paradigm to Enhance Student Learning in Engineering Education

Science.gov (United States)

El-Maaddawy, Tamer

2017-01-01

Incorporation of student self-assessment (SSA) in engineering education offers opportunities to support and encourage learner-led-learning. This paper presents an innovative assessment paradigm that integrates formative, summative, and SSA to enhance student learning. The assessment innovation was implemented in a senior-level civil engineering…

Side chain engineering of fused aromatic thienopyrazine based low band-gap polymers for enhanced charge carrier mobility

KAUST Repository

Mondal, Rajib

2011-01-01

A strategic side-chain engineering approach leads to the two orders of magnitude enhancement of charge carrier mobility in phenanthrene based fused aromatic thienopyrazine polymers. Hole carrier mobility up to 0.012 cm 2/Vs can be obtained in thin film transistor devices. Polymers were also utilized to fabricate bulk heterojunction photovoltaic devices and the maximum PCE obtained in these OPV\\'s was 1.15%. Most importantly, performances of the devices were correlated with thin morphological analysis performed by atomic force microscopy and grazing incidence X-ray scattering. © 2011 The Royal Society of Chemistry.

Commissioning and Performance Analysis of WhisperGen Stirling Engine

Science.gov (United States)

Pradip, Prashant Kaliram

Stirling engine based cogeneration systems have potential to reduce energy consumption and greenhouse gas emission, due to their high cogeneration efficiency and emission control due to steady external combustion. To date, most studies on this unit have focused on performance based on both experimentation and computer models, and lack experimental data for diversified operating ranges. This thesis starts with the commissioning of a WhisperGen Stirling engine with components and instrumentation to evaluate power and thermal performance of the system. Next, a parametric study on primary engine variables, including air, diesel, and coolant flowrate and temperature were carried out to further understand their effect on engine power and efficiency. Then, this trend was validated with the thermodynamic model developed for the energy analysis of a Stirling cycle. Finally, the energy balance of the Stirling engine was compared without and with heat recovery from the engine block and the combustion chamber exhaust.

Cyanobacterial chassis engineering for enhancing production of biofuels and chemicals.

Science.gov (United States)

Gao, Xinyan; Sun, Tao; Pei, Guangsheng; Chen, Lei; Zhang, Weiwen

2016-04-01

To reduce dependence on fossil fuels and curb greenhouse effect, cyanobacteria have emerged as an important chassis candidate for producing biofuels and chemicals due to their capability to directly utilize sunlight and CO2 as the sole energy and carbon sources, respectively. Recent progresses in developing and applying various synthetic biology tools have led to the successful constructions of novel pathways of several dozen green fuels and chemicals utilizing cyanobacterial chassis. Meanwhile, it is increasingly recognized that in order to enhance productivity of the synthetic cyanobacterial systems, optimizing and engineering more robust and high-efficient cyanobacterial chassis should not be omitted. In recent years, numerous research studies have been conducted to enhance production of green fuels and chemicals through cyanobacterial chassis modifications involving photosynthesis, CO2 uptake and fixation, products exporting, tolerance, and cellular regulation. In this article, we critically reviewed recent progresses and universal strategies in cyanobacterial chassis engineering to make it more robust and effective for bio-chemicals production.

Generation of oxy-hydrogen gas and its effect on performance of spark ignition engine

Science.gov (United States)

Patil, N. N.; Chavan, C. B.; More, A. S.; Baskar, P.

2017-11-01

Considering the current scenario of petroleum fuels, it has been observed that, they will last for few years from now. On the other hand, the ever increasing cost of a gasoline fuels and their related adverse effects on environment caught the attention of researchers to find a supplementary source. For commercial fuels, supplementary source is not about replacing the entire fuel, instead enhancing efficiency by simply making use of it in lesser amount. From the recent research that has been carried out, focus on the use of Hydrogen rich gas as a supplementary source of fuel has increased. But the problem related to the storage of hydrogen gas confines the application of pure hydrogen in petrol engine. Using oxy-hydrogen gas (HHO) generator the difficulties of storing the hydrogen have overcome up to a certain limit. The present study highlights on performance evaluation of conventional petrol engine by using HHO gas as a supplementary fuel. HHO gas was generated from the electrolysis of water. KOH solution of 3 Molar concentration was used which act as a catalyst and accelerates the rate of generation of HHO gas. Quantity of gas to be supplied to the engine was controlled by varying amount of current. It was observed that, engine performance was improved on the introduction of HHO gas.

Establishment of Systematic Design Control/Configuration Management Processes to Enhance Engineering Capability

International Nuclear Information System (INIS)

Inagaki, T.; Hamada, T.; Ihara, T.

2016-01-01

Full text: After the accident of Fukushima Daiichi Nuclear Power Plant in 2011, Tokyo Electric Power Company (TEPCO) launched various measures to enhance plant safety and safety culture of its employees. One of the important aspects of these measures is to enhance engineering capability and TEPCO is conducting actions to establish systematic design control and configuration management processes as an important foundation of such engineering capability. This paper describes how TEPCO is establishing systematic configuration management processes from three aspects, i.e., design requirement and bases management, facility configuration control, and configuration change management. It also provides brief information of the IT systems that are being introduced and will support the systematic design control and configuration management processes. (author

Performance simulation of a spark ignited free-piston engine generator

Energy Technology Data Exchange (ETDEWEB)

Mikalsen, R.; Roskilly, A.P. [Sir Joseph Swan Institute for Energy Research, University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7RU (United Kingdom)

2008-10-15

Free-piston engines are under investigation by a number of research groups worldwide due to potential fuel efficiency and engine emissions advantages. The free-piston engine generator, in which a linear electric generator is fixed to the mover to produce electric power, has been proposed as an alternative prime mover for hybrid-electric vehicles. This paper investigates the performance of a spark ignited free-piston engine generator and compares it to a conventional engine using a computational fluid dynamics simulation model. The particular operating characteristics of the free-piston engine were not found to give noticeable performance advantages, and it is concluded that the main potential of this technology lies in the simplicity and flexibility of the concept. (author)

Performance and efficiency. The flat-six engines in the new Porsche 911 Carrera; Performance und Effizienz. Die Boxermotoren im neuen Porsche 911 Carrera

Energy Technology Data Exchange (ETDEWEB)

Wasserbaech, Thomas; Kerkau, Martin; Bofinger, Gerd; Baumann, Markus; Kerner, Joerg; Neusser, Heinz-Jakob [Dr.-Ing. h.c. F. Porsche AG, Weissach (Germany)

2012-11-01

At 48 years of age, the new Porsche 911 Carrera is younger than ever. The completely redeveloped generation of the Sports Car icon has raised the bar for performance and efficiency even higher. All versions boast fuel consumption of less than ten litres per 100 kilometres. Fuel consumption and emissions are reduced by up to 16 percent compared with the predecessor. A significant contribution to this is made by the extensively optimised flat-six engines. The performance of the 3.8-litre engine in the 911 Carrera S was increased to 400 hp through further dethrottling of the intake section and the exhaust system in conjunction with optimisation of the combustion process, while consumption was reduced by 15 percent through use of the Porsche Doppelkupplung (PDK). The displacement of the 3.4-litre engine of the 911 Carrera was reduced compared with its predecessor. In this case also, engine power and acceleration values were further increased while reducing fuel consumption by 16 percent. To enhance the emotiveness of the driving experience, the revving ability of the flat engines was further improved by reducing the rotating masses and the maximum engine speed was increased to 7,800 rpm. In combination with the new 7-speed manual transmission and the Porsche Doppelkupplung (PDK), specific functions were developed which acoustically highlight the spontaneous response of the engine to the accelerator pedal and gearshift command, making the new 911 Carrera much more emotive. Auto Start Stop, coasting, thermal management, vehicle electrical system recuperation and friction-reduction measures simultaneously improve efficiency. (orig.)

Performance of Diesel Engine Using Blended Crude Jatropha Oil

Science.gov (United States)

Kamarudin, Kamarul Azhar; Mohd Sazali, Nor Shahida Akma; Mohd Ali, Mas Fauzi; Alimin, Ahmad Jais; Khir, Saffiah Abdullah

2010-06-01

Vegetable oil presents a very promising alternative to diesel oil since it is renewable and has similar properties to the diesel. In view of this, crude jatropha oil is selected and its viscosity is reduced by blending it with diesel. Since jatropha oil has properties which are similar to mineral diesel, it can be used in compression ignition engines without any engine modification. This paper presents the results of investigation carried out on a four-cylinder, four strokes and indirect-injection diesel engine. The engine, operated using composition blends of crude jatropha oil and diesel, were compared with mineral diesel. An experimental investigation has been carried out to analyze the performance characteristics of a compression ignition engine from the blended fuel (5%, 10%, 20% and 30%). A naturally aspirated four-stroke indirect injection diesel engine was tested at full load conditions, speeds between 1000 and 3500 rpm with intervals of 500 rpm. Results obtained from the measures of torque, power, specific fuel consumptions, thermal efficiency and brake mean effective pressure are nearly the same between blended and diesel fuel. An overall graph shows that the performance of relevant parameters from blended fuel is most likely similar to the performance produced from diesel. The experimental results proved that the use of crude jatropha oil in compression ignition engines is a viable alternative to diesel.

Enhanced Bank of Kalman Filters Developed and Demonstrated for In-Flight Aircraft Engine Sensor Fault Diagnostics

Science.gov (United States)

Kobayashi, Takahisa; Simon, Donald L.

2005-01-01

In-flight sensor fault detection and isolation (FDI) is critical to maintaining reliable engine operation during flight. The aircraft engine control system, which computes control commands on the basis of sensor measurements, operates the propulsion systems at the demanded conditions. Any undetected sensor faults, therefore, may cause the control system to drive the engine into an undesirable operating condition. It is critical to detect and isolate failed sensors as soon as possible so that such scenarios can be avoided. A challenging issue in developing reliable sensor FDI systems is to make them robust to changes in engine operating characteristics due to degradation with usage and other faults that can occur during flight. A sensor FDI system that cannot appropriately account for such scenarios may result in false alarms, missed detections, or misclassifications when such faults do occur. To address this issue, an enhanced bank of Kalman filters was developed, and its performance and robustness were demonstrated in a simulation environment. The bank of filters is composed of m + 1 Kalman filters, where m is the number of sensors being used by the control system and, thus, in need of monitoring. Each Kalman filter is designed on the basis of a unique fault hypothesis so that it will be able to maintain its performance if a particular fault scenario, hypothesized by that particular filter, takes place.

Biodiesel feasibility study: An evaluation of material compatibility; performance; emission and engine durability

Energy Technology Data Exchange (ETDEWEB)

Fazal, M.A.; Haseeb, A.S.M.A.; Masjuki, H.H. [Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2011-02-15

Biodiesel, derived from the transesterification of vegetable oils or animal fats, is composed of saturated and unsaturated long-chain fatty acid alkyl esters. In spite of having some application problems, recently it is being considered as one of the most promising alternative fuels in internal combustion engine. From scientific literatures, this paper has collected and analyzed the data on both advantages and disadvantages of biodiesel over conventional diesel. Since the aim of this study is to evaluate the biodiesel feasibility in automobiles, the first section is dedicated to materials compatibility in biodiesel as compared to that in diesel. The highest consensus is related to enhanced corrosion of automotive parts due to its compositional differences. In the subsequent sections, data on performance, emission and engine durability have been analyzed and compared. In this case, the highest consensus is found in reducing emissions as well as in increasing moving parts sticking, injector coking and filter plugging. This paper has also summarized the factors of biodiesel in contributing these technical performances. (author)

Performance-Enhancing Drugs: Know the Risks

Science.gov (United States)

... edge by taking muscle-building supplements or other performance-enhancing drugs? Learn how these drugs work and how they can affect your health. By ... to testosterone and estradiol in both men and women. Andro is available legally ... use as a performance-enhancing drug is illegal in the United States. ...

Design and Implementation of High-Performance GIS Dynamic Objects Rendering Engine

Science.gov (United States)

Zhong, Y.; Wang, S.; Li, R.; Yun, W.; Song, G.

2017-12-01

Spatio-temporal dynamic visualization is more vivid than static visualization. It important to use dynamic visualization techniques to reveal the variation process and trend vividly and comprehensively for the geographical phenomenon. To deal with challenges caused by dynamic visualization of both 2D and 3D spatial dynamic targets, especially for different spatial data types require high-performance GIS dynamic objects rendering engine. The main approach for improving the rendering engine with vast dynamic targets relies on key technologies of high-performance GIS, including memory computing, parallel computing, GPU computing and high-performance algorisms. In this study, high-performance GIS dynamic objects rendering engine is designed and implemented for solving the problem based on hybrid accelerative techniques. The high-performance GIS rendering engine contains GPU computing, OpenGL technology, and high-performance algorism with the advantage of 64-bit memory computing. It processes 2D, 3D dynamic target data efficiently and runs smoothly with vast dynamic target data. The prototype system of high-performance GIS dynamic objects rendering engine is developed based SuperMap GIS iObjects. The experiments are designed for large-scale spatial data visualization, the results showed that the high-performance GIS dynamic objects rendering engine have the advantage of high performance. Rendering two-dimensional and three-dimensional dynamic objects achieve 20 times faster on GPU than on CPU.

Performance Analysis with Network-Enhanced Complexities: On Fading Measurements, Event-Triggered Mechanisms, and Cyber Attacks

Directory of Open Access Journals (Sweden)

Derui Ding

2014-01-01

Full Text Available Nowadays, the real-world systems are usually subject to various complexities such as parameter uncertainties, time-delays, and nonlinear disturbances. For networked systems, especially large-scale systems such as multiagent systems and systems over sensor networks, the complexities are inevitably enhanced in terms of their degrees or intensities because of the usage of the communication networks. Therefore, it would be interesting to (1 examine how this kind of network-enhanced complexities affects the control or filtering performance; and (2 develop some suitable approaches for controller/filter design problems. In this paper, we aim to survey some recent advances on the performance analysis and synthesis with three sorts of fashionable network-enhanced complexities, namely, fading measurements, event-triggered mechanisms, and attack behaviors of adversaries. First, these three kinds of complexities are introduced in detail according to their engineering backgrounds, dynamical characteristic, and modelling techniques. Then, the developments of the performance analysis and synthesis issues for various networked systems are systematically reviewed. Furthermore, some challenges are illustrated by using a thorough literature review and some possible future research directions are highlighted.

Airbreathing Pulse Detonation Engine Performance

Science.gov (United States)

Povinelli, Louis A.; Yungster, Shaye

2002-01-01

This paper presents performance results for pulse detonation engines (PDE) taking into account the effects of dissociation and recombination. The amount of sensible heat recovered through recombination in the PDE chamber and exhaust process was found to be significant. These results have an impact on the specific thrust, impulse and fuel consumption of the PDE.

THE EFFECT OF COMPRESSION RATIO VARIATIONS ON THE ENGINE PERFORMANCE PARAMETRES IN SPARK IGNITION ENGINES

Directory of Open Access Journals (Sweden)

Yakup SEKMEN

2005-01-01

Full Text Available Performance of the spark ignition engines may be increased by changing the geometrical compression ratio according to the amount of charging in cylinders. The designed geometrical compression ratio can be realized as an effective compression ratio under the full load and full open throttle conditions since the effective compression ratio changes with the amount of charging into the cylinder in spark ignition engines. So, this condition of the spark ignition engines forces designers to change their geometrical compression ratio according to the amount of charging into the cylinder for improvement of performance and fuel economy. In order to improve the combustion efficiency, fuel economy, power output, exhaust emissions at partial loads, compression ratio must be increased; but, under high load and low speed conditions to prevent probable knock and hard running the compression ratio must be decreased gradually. In this paper, relation of the performance parameters to compression ratio such as power, torque, specific fuel consumption, cylindir pressure, exhaust gas temperature, combustion chamber surface area/volume ratio, thermal efficiency, spark timing etc. in spark ignition engines have been investigated and using of engines with variable compression ratio is suggested to fuel economy and more clear environment.

A Microfabricated Segmented-Involute-Foil Regenerator for Enhancing Reliability and Performance of Stirling Engines

Science.gov (United States)

Ibrahim, Mounir; Danila, Daniel; Simon, Terrence; Mantell, Susan; Sun, Liyong; Gadeon, David; Qiu, Songgang; Wood, Gary; Kelly, Kevin; McLean, Jeffrey

2007-01-01

An actual-size microfabricated regenerator comprised of a stack of 42 disks, 19 mm diameter and 0.25 mm thick, with layers of microscopic, segmented, involute-shaped flow channels was fabricated and tested. The geometry resembles layers of uniformly-spaced segmented-parallel-plates, except the plates are curved. Each disk was made from electro-plated nickel using the LiGA process. This regenerator had feature sizes close to those required for an actual Stirling engine but the overall regenerator dimensions were sized for the NASA/Sunpower oscillating-flow regenerator test rig. Testing in the oscillating-flow test rig showed the regenerator performed extremely well, significantly better than currently used random-fiber material, producing the highest figures of merit ever recorded for any regenerator tested in that rig over its approximately 20 years of use.

Effect of replacing nitrogen with helium on a closed cycle diesel engine performance

Directory of Open Access Journals (Sweden)

Alaa M. Abo El Ela

2016-09-01

Full Text Available One of most important problems of closed cycle diesel engine is deterioration of cylinder pressure and consequently the engine power. Therefore this research aimed to establish a multi zone model using Computational Fluid Dynamic (CFD code; ANSYS Fluent 14.0 to enhance the closed cycle diesel engine performance. The present work investigates the effect of replacing nitrogen gas with helium gas in different concentration under different engine load and equivalence ratios. The numerical model results were validated with comparing them with those obtained from the previous experimental results. The engine which was used for the simulation analysis and the previous experimental work was a single cylinder with a displacement volume of 825 cm3, compression ratio of 17 and run at constant speed of 1500 RPM. The numerical results showed that replacing nitrogen with helium resulted in increasing the in-cylinder pressure. The results showed also that a percentage of 0.5–10% of helium on mass basis is sufficient in the recovery needed to overcome the drop in-cylinder pressure and hence power due to the existence of CO2 in the recycled gas up to 25%. When the CO2 % reaches 25%, it is required to use at least 10% of He as replacement gas to achieve the required recovery.

Sleep Deprivation Impairs and Caffeine Enhances My Performance, but Not Always Our Performance.

Science.gov (United States)

Faber, Nadira S; Häusser, Jan A; Kerr, Norbert L

2017-02-01

What effects do factors that impair or enhance performance in individuals have when these individuals act in groups? We provide a framework, called the GIE ("Effects of Grouping on Impairments and Enhancements") framework, for investigating this question. As prominent examples for individual-level impairments and enhancements, we discuss sleep deprivation and caffeine. Based on previous research, we derive hypotheses on how they influence performance in groups, specifically process gains and losses in motivation, individual capability, and coordination. We conclude that the effect an impairment or enhancement has on individual-level performance is not necessarily mirrored in group performance: grouping can help or hurt. We provide recommendations on how to estimate empirically the effects individual-level performance impairments and enhancements have in groups. By comparing sleep deprivation to stress and caffeine to pharmacological cognitive enhancement, we illustrate that we cannot readily generalize from group results on one impairment or enhancement to another, even if they have similar effects on individual-level performance.

Biogas engine performance estimation using ANN

Directory of Open Access Journals (Sweden)

Yusuf Kurtgoz

2017-12-01

Full Text Available Artificial neural network (ANN method was used to estimate the thermal efficiency (TE, brake specific fuel consumption (BSFC and volumetric efficiency (VE values of a biogas engine with spark ignition at different methane (CH4 ratios and engine load values. For this purpose, the biogas used in the biogas engine was produced by the anaerobic fermentation method from bovine manure and different CH4 contents (51%, 57%, 87% were obtained by purification of CO2 and H2S. The data used in the ANN models were obtained experimentally from a 4-stroke four-cylinder, spark ignition engine, at constant speed for different load and CH4 ratios. Using some of the obtained experimental data, ANN models were developed, and the rest was used to test the developed models. In the ANN models, the CH4 ratio of the fuel, engine load, inlet air temperature (Tin, air fuel ratio and the maximum cylinder pressure are chosen as the input parameters. TE, BSFC and VE are used as the output parameters. Root mean square error (RMSE, mean absolute percentage error (MAPE and correlation coefficient (R performance indicators are used to compare measured and predicted values. It has been shown that ANN models give good results in spark ignition biogas engines with high correlation and low error rates for TE, BSFC and VE values.

Bio-Engineering High Performance Microbial Strains for MEOR

Energy Technology Data Exchange (ETDEWEB)

Xiangdong Fang; Qinghong Wang; Patrick Shuler

2007-12-30

The main objectives of this three-year research project are: (1) to employ the latest advances in genetics and bioengineering, especially Directed Protein Evolution technology, to improve the effectiveness of the microbial enhanced oil recovery (MEOR) process. (2) to improve the surfactant activity and the thermal stability of bio-surfactant systems for MEOR; and (3) to develop improved laboratory methods and tools that screen quickly candidate bio-systems for EOR. Biosurfactants have been receiving increasing attention as Enhanced Oil Recovery (EOR) agents because of their unique properties (i.e., mild production conditions, lower toxicity, and higher biodegradability) compared to their synthetic chemical counterparts. Rhamnolipid as a potent natural biosurfactant has a wide range of potential applications, including EOR and bioremediation. During the three-year of the project period, we have successfully cloned the genes involved in the rhamnolipid bio-synthesis. And by using the Transposon containing Rhamnosyltransferase gene rhlAB, we engineered the new mutant strains P. aeruginosa PEER02 and E. coli TnERAB so they can produce rhamnolipid biosurfactans. We were able to produce rhamnolipds in both P. aeroginosa PAO1-RhlA- strain and P. fluorescens ATCC15453 strain, with the increase of 55 to 175 fold in rhamnolipid production comparing with wild type bacteria strain. We have also completed the first round direct evolution studies using Error-prone PCR technique and have constructed the library of RhlAB-containing Transposon to express mutant gene in heterologous hosts. Several methods, such as colorimetric agar plate assay, colorimetric spectrophotometer assay, bioactive assay and oil spreading assay have been established to detect and screen rhamnolipid production. Our engineered P. aeruginosa PEER02 strain can produce rhamnolipids with different carbon sources as substrate. Interfacial tension analysis (IFT) showed that different rhamnolipids from different

Prediction of small spark ignited engine performance using producer gas as fuel

Directory of Open Access Journals (Sweden)

N. Homdoung

2015-03-01

Full Text Available Producer gas from biomass gasification is expected to contribute to greater energy mix in the future. Therefore, effect of producer gas on engine performance is of great interest. Evaluation of engine performances can be hard and costly. Ideally, they may be predicted mathematically. This work was to apply mathematical models in evaluating performance of a small producer gas engine. The engine was a spark ignition, single cylinder unit with a CR of 14:1. Simulation was carried out on full load and varying engine speeds. From simulated results, it was found that the simple mathematical model can predict the performance of the gas engine and gave good agreement with experimental results. The differences were within ±7%.

Effect of Injector Nozzle Holes on Diesel Engine Performance

OpenAIRE

Semin,; Yusof, Mohd Yuzri Mohd; Arof, Aminuddin Md; Shaharudin, Daneil Tomo; Ismail, Abdul Rahim

2010-01-01

All of the injector nozzle holes have examined and the results are shown that the seven holes nozzle have provided the best burning result for the fuel in-cylinder burned in any different engine speeds and the best burning is in low speed engine. In engine performance effect, all of the nozzles have examined and the five holes nozzle provided the best result in indicted power, indicated torque and ISFC in any different engine speeds.

Rock armour for birds and their prey: ecological enhancement of coastal engineering

OpenAIRE

Naylor, Larissa A.; MacArthur, Mairi; Hampshire, Stephanie; Bostock, Kieran; Coombes, Martin A.; Hansom, Jim; Byrne, Rowan; Folland, Tristan

2017-01-01

The authors present key design, construction and ecological enhancement criteria for sustainable coastal defence structures at Hartlepool, UK, a high-energy wave climate. Such ‘ecologically favourable’ coastal defences fulfil the habitats directive and key engineering and cost criteria. Bird, rocky intertidal ecological and biogeomorphological data underpin recommendations for ‘passive’ enhancement mitigation to maximise ecological potential involving rock armour material choice (partially en...

Windmilling of turbofan engine; calculation of performance characteristics of a turbofan engine under windmilling

OpenAIRE

Ramanathan, A.

2014-01-01

The turbofan is a type of air breathing jet engine that finds wide use in aircraft propulsion. During the normal operation of a turbofan engine installed in aircraft, the combustor is supplied with fuel, flow to the combustor is cut off and the engine runs under so called Windmilling conditions being driven only by the ram pressure ratio by producing drag. In-depth analysis is done to study the performance characteristics at this state.

Engine performance and emissions characteristics of a diesel engine fueled with diesel-biodiesel-bioethanol emulsions

International Nuclear Information System (INIS)

Tan, Yie Hua; Abdullah, Mohammad Omar; Nolasco-Hipolito, Cirilo; Zauzi, Nur Syuhada Ahmad; Abdullah, Georgie Wong

2017-01-01

Highlights: • Different composition of diesel fuel, biodiesel and bioethanol emulsions were examined. • The fuels were tested in a direct injection diesel engine and parameters were evaluated. • Engine power, torque, exhaust gas temperature & fuel consumptions were compared. • Emulsions fuels emitted lower CO and CO_2 than fossil diesel. • Lower NOx emission was observed at medium engine speeds and loads for emulsion fuels. - Abstract: In this research work, the experimental investigation of the effect of diesel-biodiesel-bioethanol emulsion fuels on combustion, performance and emission of a direct injection (DI) diesel engine are reported. Four kind of emulsion fuels were employed: B (diesel-80%, biodiesel-20% by volume), C (diesel-80%, biodiesel-15%, bioethanol-5%), D (diesel-80%, biodiesel-10%, bioethanol-10%) and E (diesel-80%, biodiesel-5%, bioethanol-15%) to compare its’ performance with the conventional diesel, A. These emulsion fuels were prepared by mechanical homogenizer machine with the help of Tween 80 (1% v/v) and Span 80 (0.5% v/v) as surfactants. The emulsion characteristics were determined by optical electron microscope, emulsification stability test, FTIR, and the physiochemical properties of the emulsion fuels which were all done by following ASTM test methods. The prepared emulsion fuels were then tested in diesel engine test bed to obtain engine performance and exhaust emissions. All the engine experiments were conducted with engine speeds varying from 1600 to 2400 rpm. The results showed the heating value and density of the emulsion fuels decrease as the bioethanol content in the blend increases. The total heating value of the diesel-biodiesel-bioethanol fuels were averagely 21% higher than the total heating value of the pure biodiesel and slightly lower (2%) than diesel fuel. The engine power, torque and exhaust gas temperature were reduced when using emulsion fuels. The brake specific fuel consumption (BSFC) for the emulsion fuels

Performance of discrete heat engines and heat pumps in finite time

Science.gov (United States)

Feldmann; Kosloff

2000-05-01

The performance in finite time of a discrete heat engine with internal friction is analyzed. The working fluid of the engine is composed of an ensemble of noninteracting two level systems. External work is applied by changing the external field and thus the internal energy levels. The friction induces a minimal cycle time. The power output of the engine is optimized with respect to time allocation between the contact time with the hot and cold baths as well as the adiabats. The engine's performance is also optimized with respect to the external fields. By reversing the cycle of operation a heat pump is constructed. The performance of the engine as a heat pump is also optimized. By varying the time allocation between the adiabats and the contact time with the reservoir a universal behavior can be identified. The optimal performance of the engine when the cold bath is approaching absolute zero is studied. It is found that the optimal cooling rate converges linearly to zero when the temperature approaches absolute zero.

Engineering Performance of Polyurethane Bonded Aggregates

Directory of Open Access Journals (Sweden)

Haimin WU

2017-08-01

Full Text Available In this paper the engineering performance of polyurethane (PUR bonded aggregate were studied. The engineering performance, including compressive and flexural mechanical properties, void ratio, and coefficient of permeability were determined through laboratory tests. Moreover, the effects of two different curing conditions on the compressive strength properties of a PUR bonded aggregate were also evaluated. The compressive strengths of PUR bonded aggregates were found to be lower than that of conventional porous concrete, which is a commonly used cushion material. However, experimental results indicated a higher void ratio and coefficient of permeability, lower elasticity modulus, better toughness, and stronger adaptability to flexural deformation compared to porous concrete. Consequently, PUR bonded aggregate is a better solution than porous concrete when used as the cushion material of a geomembrane surface barrier for a high rock-fill dam.DOI: http://dx.doi.org/10.5755/j01.ms.23.2.15798

Fire-safety engineering and performance-based codes

DEFF Research Database (Denmark)

Sørensen, Lars Schiøtt

project administrators, etc. The book deals with the following topics: • Historical presentation on the subject of fire • Legislation and building project administration • European fire standardization • Passive and active fire protection • Performance-based Codes • Fire-safety Engineering • Fundamental......Fire-safety Engineering is written as a textbook for Engineering students at universities and other institutions of higher education that teach in the area of fire. The book can also be used as a work of reference for consulting engineers, Building product manufacturers, contractors, building...... thermodynamics • Heat exchange during the fire process • Skin burns • Burning rate, energy release rate and design fires • Proposal to Risk-based design fires • Proposal to a Fire scale • Material ignition and flame spread • Fire dynamics in buildings • Combustion products and toxic gases • Smoke inhalation...

Adaptation Method for Overall and Local Performances of Gas Turbine Engine Model

Science.gov (United States)

Kim, Sangjo; Kim, Kuisoon; Son, Changmin

2018-04-01

An adaptation method was proposed to improve the modeling accuracy of overall and local performances of gas turbine engine. The adaptation method was divided into two steps. First, the overall performance parameters such as engine thrust, thermal efficiency, and pressure ratio were adapted by calibrating compressor maps, and second, the local performance parameters such as temperature of component intersection and shaft speed were adjusted by additional adaptation factors. An optimization technique was used to find the correlation equation of adaptation factors for compressor performance maps. The multi-island genetic algorithm (MIGA) was employed in the present optimization. The correlations of local adaptation factors were generated based on the difference between the first adapted engine model and performance test data. The proposed adaptation method applied to a low-bypass ratio turbofan engine of 12,000 lb thrust. The gas turbine engine model was generated and validated based on the performance test data in the sea-level static condition. In flight condition at 20,000 ft and 0.9 Mach number, the result of adapted engine model showed improved prediction in engine thrust (overall performance parameter) by reducing the difference from 14.5 to 3.3%. Moreover, there was further improvement in the comparison of low-pressure turbine exit temperature (local performance parameter) as the difference is reduced from 3.2 to 0.4%.

Effect of temperature change at inlet of engine on the corrected performance of turbofan engine

Energy Technology Data Exchange (ETDEWEB)

Kozu, Masao; Yajima, Satoshi [Defence Agency, Tokyo, JapanIshikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

1989-06-10

Theoretical consideration on the effect of inlet temperature change of engine on the engine performance was conducted, and soundness of the result was appreciated by applying it to the experimental result of turbofan engine. As the theoretical consideration, premises of Buckingham's fundamental theorem was corrected by Reynolds Number and by the consideration on the effect of inlet temperature on gas constant and specific heat ratio. By using the result, correction factors were calculated from the experimental result of an actual turbo-fan engine. The correction factors were applied to the other engine test result and confirmed satisfactory soundness. 4 refs., 11 figs.

Enhancing gold recovery from electronic waste via lixiviant metabolic engineering in Chromobacterium violaceum

Science.gov (United States)

Tay, Song Buck; Natarajan, Gayathri; Rahim, Muhammad Nadjad bin Abdul; Tan, Hwee Tong; Chung, Maxey Ching Ming; Ting, Yen Peng; Yew, Wen Shan

2013-01-01

Conventional leaching (extraction) methods for gold recovery from electronic waste involve the use of strong acids and pose considerable threat to the environment. The alternative use of bioleaching microbes for gold recovery is non-pollutive and relies on the secretion of a lixiviant or (bio)chemical such as cyanide for extraction of gold from electronic waste. However, widespread industrial use of bioleaching microbes has been constrained by the limited cyanogenic capabilities of lixiviant-producing microorganisms such as Chromobacterium violaceum. Here we show the construction of a metabolically-engineered strain of Chromobacterium violaceum that produces more (70%) cyanide lixiviant and recovers more than twice as much gold from electronic waste compared to wild-type bacteria. Comparative proteome analyses suggested the possibility of further enhancement in cyanogenesis through subsequent metabolic engineering. Our results demonstrated the utility of lixiviant metabolic engineering in the construction of enhanced bioleaching microbes for the bioleaching of precious metals from electronic waste. PMID:23868689

Performance and exhaust emissions of a biodiesel engine

Energy Technology Data Exchange (ETDEWEB)

Canakci, Mustafa [Kocaeli University, Technical Education Faculty, 41380 Kocaeli (Turkey); Erdil, Ahmet [Kocaeli University, Engineering Faculty, 41040 Kocaeli (Turkey); Arcaklioglu, Erol [Kirikkale University, Engineering Faculty, 71450 Kirikkale (Turkey)

2006-06-15

In this study, the applicabilities of Artificial Neural Networks (ANNs) have been investigated for the performance and exhaust-emission values of a diesel engine fueled with biodiesels from different feedstocks and petroleum diesel fuels. The engine performance and emissions characteristics of two different petroleum diesel-fuels (No. 1 and No. 2), biodiesels (from soybean oil and yellow grease), and their 20% blends with No. 2 diesel fuel were used as experimental results. The fuels were tested at full load (100%) at 1400-rpm engine speed, where the engine torque was 257.6Nm. To train the network, the average molecular weight, net heat of combustion, specific gravity, kinematic viscosity, C/H ratio and cetane number of each fuel are used as the input layer, while outputs are the brake specific fuel-consumption, exhaust temperature, and exhaust emissions. The back-propagation learning algorithm with three different variants, single layer, and logistic sigmoid transfer function were used in the network. By using weights in the network, formulations have been given for each output. The network has yielded R{sup 2} values of 0.99 and the mean % errors are smaller than 4.2 for the training data, while the R{sup 2} values are about 0.99 and the mean % errors are smaller than 5.5 for the test data. The performance and exhaust emissions from a diesel engine, using biodiesel blends with No. 2 diesel fuel up to 20%, have been predicted using the ANN model. sing the ANN model. (author)

High Performance Computing in Science and Engineering '14

CERN Document Server

Kröner, Dietmar; Resch, Michael

2015-01-01

This book presents the state-of-the-art in supercomputer simulation. It includes the latest findings from leading researchers using systems from the High Performance Computing Center Stuttgart (HLRS). The reports cover all fields of computational science and engineering ranging from CFD to computational physics and from chemistry to computer science with a special emphasis on industrially relevant applications. Presenting findings of one of Europe’s leading systems, this volume covers a wide variety of applications that deliver a high level of sustained performance. The book covers the main methods in high-performance computing. Its outstanding results in achieving the best performance for production codes are of particular interest for both scientists and   engineers. The book comes with a wealth of color illustrations and tables of results.  

A review on the engine performance and exhaust emission characteristics of diesel engines fueled with biodiesel blends.

Science.gov (United States)

Damanik, Natalina; Ong, Hwai Chyuan; Tong, Chong Wen; Mahlia, Teuku Meurah Indra; Silitonga, Arridina Susan

2018-06-01

Biodiesels have gained much popularity because they are cleaner alternative fuels and they can be used directly in diesel engines without modifications. In this paper, a brief review of the key studies pertaining to the engine performance and exhaust emission characteristics of diesel engines fueled with biodiesel blends, exhaust aftertreatment systems, and low-temperature combustion technology is presented. In general, most biodiesel blends result in a significant decrease in carbon monoxide and total unburned hydrocarbon emissions. There is also a decrease in carbon monoxide, nitrogen oxide, and total unburned hydrocarbon emissions while the engine performance increases for diesel engines fueled with biodiesels blended with nano-additives. The development of automotive technologies, such as exhaust gas recirculation systems and low-temperature combustion technology, also improves the thermal efficiency of diesel engines and reduces nitrogen oxide and particulate matter emissions.

Rotary engine performance computer program (RCEMAP and RCEMAPPC): User's guide

Science.gov (United States)

Bartrand, Timothy A.; Willis, Edward A.

1993-01-01

This report is a user's guide for a computer code that simulates the performance of several rotary combustion engine configurations. It is intended to assist prospective users in getting started with RCEMAP and/or RCEMAPPC. RCEMAP (Rotary Combustion Engine performance MAP generating code) is the mainframe version, while RCEMAPPC is a simplified subset designed for the personal computer, or PC, environment. Both versions are based on an open, zero-dimensional combustion system model for the prediction of instantaneous pressures, temperature, chemical composition and other in-chamber thermodynamic properties. Both versions predict overall engine performance and thermal characteristics, including bmep, bsfc, exhaust gas temperature, average material temperatures, and turbocharger operating conditions. Required inputs include engine geometry, materials, constants for use in the combustion heat release model, and turbomachinery maps. Illustrative examples and sample input files for both versions are included.

Effect of finite heat input on the power performance of micro heat engines

International Nuclear Information System (INIS)

Khu, Kerwin; Jiang, Liudi; Markvart, Tom

2011-01-01

Micro heat engines have attracted considerable interest in recent years for their potential exploitation as micro power sources in microsystems and portable devices. Thermodynamic modeling can predict the theoretical performance that can be potentially achieved by micro heat engine designs. An appropriate model can not only provide key information at the design stage but also indicate the potential room for improvement in existing micro heat engines. However, there are few models reported to date which are suitable for evaluating the power performance of micro heat engines. This paper presents a new thermodynamic model for determining the theoretical limit of power performance of micro heat engines with consideration to finite heat input and heat leakage. By matching the model components to those of a representative heat engine layout, the theoretical power, power density, and thermal efficiency achievable for a micro heat engine can be obtained for a given set of design parameters. The effects of key design parameters such as length and thermal conductivity of the engine material on these theoretical outputs are also investigated. Possible trade-offs among these performance objectives are discussed. Performance results derived from the developed model are compared with those of a working micro heat engine (P3) as an example. -- Highlights: → Thermodynamic model for micro heat engines. → Effect of different parameters on potential performance. → Tradeoffs for determining optimal size of micro engines.

Final Report: Performance Engineering Research Institute

Energy Technology Data Exchange (ETDEWEB)

Mellor-Crummey, John [Rice Univ., Houston, TX (United States)

2014-10-27

This document is a final report about the work performed for cooperative agreement DE-FC02-06ER25764, the Rice University effort of Performance Engineering Research Institute (PERI). PERI was an Enabling Technologies Institute of the Scientific Discovery through Advanced Computing (SciDAC-2) program supported by the Department of Energy's Office of Science Advanced Scientific Computing Research (ASCR) program. The PERI effort at Rice University focused on (1) research and development of tools for measurement and analysis of application program performance, and (2) engagement with SciDAC-2 application teams.

Further developments in performance prediction techniques of adiabatic diesel engines

Energy Technology Data Exchange (ETDEWEB)

Rasihhan, Y

1990-01-01

The engine cycle simulation program 'SPICE', developed at Bath University, has been used extensively for insulated diesel engine research. The present study introduces more comprehensive engine heat transfer models thus enabling us to study the insulated engine heat transfer and performance characteristics in more detail. The new version of 'SPICE' separates the gas to wall heat transfer into two parts, convective and radiative. For this purpose, a detailed radiative heat transfer model which considers both the flame (gas and soot) and wall to wall radiative heat transfer is written. The previous engine resistance model is refined and replaced by a more detailed resistance model which considers piston-liner conduction heat transfer and 2-D heat flow in the liner. The wall surface temperature swing is also included in the engine heat transfer calculations which is quite significant in low conductivity ceramic insulated engines. A 1-D finite difference model is written for the transient heat transfer region of the wall and linked to the engine resistance model. This new version of 'SPICE' is used to predict the insulated engine heat transfer and performance for the experimental Petter PH1W engine for various insulation levels and schemes. An answer to the controversy of increase in engine heat loss with insulation is looked for. The effect of wall deposits on engine heat transfer and its significance for the insulated engine is highlighted. (Author).

Modelling the long-term isolation performance of natural and engineered geologic CO{sub 2} storage sites

Energy Technology Data Exchange (ETDEWEB)

Johnson, J.W.; Nitao, J.J.; Morris, J.P. [California Univ., Livermore, CA (United States). Lawrence Livermore National Laboratory

2005-07-01

Caprock integrity is an important constraint on the long-term performance of natural and engineered carbon dioxide (CO{sub 2}) sequestration sites. Influxes of CO{sub 2} can lead to concomitant geochemical alteration and geomechanical deformation of the caprock and degrade seal integrity. In this study, reactive transport modelling was used to assess the evolution of caprock permeability. The model was based on mathematical models of the coupled physical and chemical processes catalyzed by an influx event, along with supporting geochemical databases and a distinct-element geomechanical model. Geomechanical contribution was evaluated within a full system analysis of coupled hydrological and geochemical processes for Sleipner-like settings, and then analyzed as a function of hydrological processes, key reservoir properties, and CO{sub 2} influx parameters. The net effect of the geomechanical and geomechanical contributions on caprock integrity was then evaluated for both natural and engineered storage scenarios. Results of the study showed that CO{sub 2} influx-triggered geochemical and geomechanical processes act in opposition to enhance and degrade hydrodynamic seal capacity through aperture narrowing and widening of microfractures. The extent of geochemical enhancement was independent of the reservoir characteristics that distinguished saline-aquifer from enhanced oil recovery and CO{sub 2} sequestration settings. However, while the extent of geochemical alteration was nearly independent of the filling mode, geomechanical deformation processes were more pronounced in engineered storage scenarios. Results suggested that the secure caprocks of natural CO{sub 2} accumulation settings may be incapable of providing effective seals for engineered injection processes. The pressure increase associated with CO{sub 2} accumulation in any compartmentalized system resulted in the net geomechanical aperture widening of caprock microfractures. It was concluded that the

Effect of biodiesel blends on engine performance and exhaust emission for diesel dual fuel engine

International Nuclear Information System (INIS)

Mohsin, R.; Majid, Z.A.; Shihnan, A.H.; Nasri, N.S.; Sharer, Z.

2014-01-01

Highlights: • Engine and emission characteristics of biodiesel DDF engine system were measured. • Biodiesel DDF fuelled system produced high engine performance. • Lower hydrocarbons and carbon dioxide was emitted by biodiesel DDF system. • Biodiesel DDF produced slightly higher carbon monoxide and nitric oxides emission. - Abstract: Biodiesel derived from biomass is a renewable source of fuel. It is renovated to be the possible fuel to replace fossil derived diesel due to its properties and combustion characteristics. The integration of compressed natural gas (CNG) in diesel engine known as diesel dual fuel (DDF) system offered better exhaust emission thus become an attractive option for reducing the pollutants emitted from transportation fleets. In the present study, the engine performance and exhaust emission of HINO H07C DDF engine; fuelled by diesel, biodiesel, diesel–CNG, and biodiesel–CNG, were experimentally studied. Biodiesel and diesel fuelled engine system respectively generated 455 N m and 287 N m of torque. The horse power of biodiesel was found to be 10–20% higher compared to diesel. Biodiesel–CNG at 20% (B20-DDF) produced the highest engine torque compared to other fuel blends Biodiesel significantly increase the carbon monoxide (15–32%) and nitric oxides (6.67–7.03%) but in contrast reduce the unburned hydrocarbons (5.76–6.25%) and carbon dioxide (0.47–0.58%) emissions level. These results indicated that biodiesel could be used without any engine modifications as an alternative and environmentally friendly fuel especially the heavy transportation fleets

Adjusting the specificity of an engine map based on the sensitivity of an engine control parameter relative to a performance variable

Science.gov (United States)

Jiang, Li; Lee, Donghoon; Yilmaz, Hakan; Stefanopoulou, Anna

2014-10-28

Methods and systems for engine control optimization are provided. A first and a second operating condition of a vehicle engine are detected. An initial value is identified for a first and a second engine control parameter corresponding to a combination of the detected operating conditions according to a first and a second engine map look-up table. The initial values for the engine control parameters are adjusted based on a detected engine performance variable to cause the engine performance variable to approach a target value. A first and a second sensitivity of the engine performance variable are determined in response to changes in the engine control parameters. The first engine map look-up table is adjusted when the first sensitivity is greater than a threshold, and the second engine map look-up table is adjusted when the second sensitivity is greater than a threshold.

Applying lessons learned to enhance human performance and reduce human error for ISS operations

Energy Technology Data Exchange (ETDEWEB)

Nelson, W.R.

1998-09-01

A major component of reliability, safety, and mission success for space missions is ensuring that the humans involved (flight crew, ground crew, mission control, etc.) perform their tasks and functions as required. This includes compliance with training and procedures during normal conditions, and successful compensation when malfunctions or unexpected conditions occur. A very significant issue that affects human performance in space flight is human error. Human errors can invalidate carefully designed equipment and procedures. If certain errors combine with equipment failures or design flaws, mission failure or loss of life can occur. The control of human error during operation of the International Space Station (ISS) will be critical to the overall success of the program. As experience from Mir operations has shown, human performance plays a vital role in the success or failure of long duration space missions. The Department of Energy`s Idaho National Engineering and Environmental Laboratory (INEEL) is developed a systematic approach to enhance human performance and reduce human errors for ISS operations. This approach is based on the systematic identification and evaluation of lessons learned from past space missions such as Mir to enhance the design and operation of ISS. This paper describes previous INEEL research on human error sponsored by NASA and how it can be applied to enhance human reliability for ISS.

Multivariate Analysis of Students' Performance in Math Courses and Specific Engineering Courses

OpenAIRE

H. Naccache; R. Hleiss

2016-01-01

The aim of this research is to study the relationship between the performance of engineering students in different math courses and their performance in specific engineering courses. The considered courses are taken mainly by engineering students during the first two years of their major. Several factors are being studied, such as gender and final grades in the math and specific engineering courses. Participants of this study comprised a sample of more than thousands of engineering students a...

PERFORMANCE IMPROVEMENT OF DIESEL ENGINE THROUGH VARIOUS ADVANCEMENTS IN TURBOCHARGING TECHNOLOGY: A REVIEW

OpenAIRE

A.F. Sherwani

2016-01-01

In this paper, the effect of various advancements in turbocharging technology on diesel engine power, fuel consumption, thermal efficiency, volumetric efficiency and emissions are reviewed and analyzed.Turbochargers are used throughout the automotive industry to enhance the output of an internal combustion engine without increasing the cylinder capacity. The emphasis today is to provide a feasible engineering solution to manufacturing economics and greener road vehicles. It is because of thes...

An experimental study of the effect of octane number higher than engine requirement on the engine performance and emissions

Energy Technology Data Exchange (ETDEWEB)

Sayin, Cenk; Kilicaslan, Ibrahim; Canakci, Mustafa; Ozsezen, Necati [Kocaeli Univ., Dept. of Mechanical Education, Izmit (Turkey)

2005-06-01

In this study, the effect of using higher-octane gasoline than that of engine requirement on the performance and exhaust emissions was experimentally studied. The test engine chosen has a fuel system with carburettor because 60% of the vehicles in Turkey are equipped with the carburettor. The engine, which required 91-RON (Research Octane Number) gasoline, was tested using 95-RON and 91-RON. Results show that using octane ratings higher than the requirement of an engine not only decreases engine performance but also increases exhaust emissions. (Author)

Performance Testing of Diesel Engine using Cardanol-Kerosene oil blend

Directory of Open Access Journals (Sweden)

Ravindra

2018-01-01

Full Text Available Awareness of environmental pollution and fossil fuel depletion has necessitated the use of biofuels in engines which have a relatively cleaner emissions. Cardanol is a biofuel, abundantly available in India, which is a by-product of cashew processing industries. In this study performance of raw Cardanol blended with kerosene has been tested in diesel engine. Volumetric blend BK30 (30% kerosene and 70% Cardanol has been used for the test. The properties like flash point, viscosity and calorific value of the blend have been determined. The test was carried out in four stroke diesel engine connected with an eddy current dynamometer. Performance of the engine has been analysed by finding the brake specific fuel consumption (BSFC and brake thermal efficiency (BTE. The results showed that the brake thermal efficiency of the blend is 29.87%, with less CO and smoke emission compared to diesel. The results were also compared with the performance of Cardanol diesel blend and Cardanol camphor oil blend, which were already tested in diesel engines by other researchers. Earlier research work reveals that the blend of 30% camphor oil and 70% Cardanol performs very closer to diesel fuel with a thermal efficiency of 29.1%. Similarly, higher brake thermal efficiency was obtained for 20% Cardanol and 80% diesel blend.

Investigating the effects of LPG on spark ignition engine combustion and performance

International Nuclear Information System (INIS)

Bayraktar, Hakan; Durgun, Orhan

2005-01-01

A quasi-dimensional spark ignition (SI) engine cycle model is used to predict the cycle, performance and exhaust emissions of an automotive engine for the cases of using gasoline and LPG. Governing equations of the mathematical model mainly consist of first order ordinary differential equations derived for cylinder pressure and temperature. Combustion is simulated as a turbulent flame propagation process and during this process, two different thermodynamic regions consisting of unburned gases and burned gases that are separated by the flame front are considered. A computer code for the cycle model has been prepared to perform numerical calculations over a range of engine speeds and fuel-air equivalence ratios. In the computations performed at different engine speeds, the same fuel-air equivalence ratios are selected for each fuel to make realistic comparisons from the fuel economy and fuel consumption points of view. Comparisons show that if LPG fueled SI engines are operated at the same conditions with those of gasoline fueled SI engines, significant improvements in exhaust emissions can be achieved. However, variations in various engine performance parameters and the effects on the engine structural elements are not promising

The exercise-induced biochemical milieu enhances collagen content and tensile strength of engineered ligaments.

Science.gov (United States)

West, Daniel W D; Lee-Barthel, Ann; McIntyre, Todd; Shamim, Baubak; Lee, Cassandra A; Baar, Keith

2015-10-15

Exercise stimulates a dramatic change in the concentration of circulating hormones, such as growth hormone (GH), but the biological functions of this response are unclear. Pharmacological GH administration stimulates collagen synthesis; however, whether the post-exercise systemic milieu has a similar action is unknown. We aimed to determine whether the collagen content and tensile strength of tissue-engineered ligaments is enhanced by serum obtained post-exercise. Primary cells from a human anterior cruciate ligament (ACL) were used to engineer ligament constructs in vitro. Blood obtained from 12 healthy young men 15 min after resistance exercise contained GH concentrations that were ∼7-fold greater than resting serum (P Ligament constructs were treated for 7 days with medium supplemented with serum obtained at rest (RestTx) or 15 min post-exercise (ExTx), before tensile testing and collagen content analysis. Compared with RestTx, ExTx enhanced collagen content (+19%; 181 ± 33 vs. 215 ± 40 μg per construct P = 0.001) and ligament mechanical properties - maximal tensile load (+17%, P = 0.03 vs. RestTx) and ultimate tensile strength (+10%, P = 0.15 vs. RestTx). In a separate set of engineered ligaments, recombinant IGF-1, but not GH, enhanced collagen content and mechanics. Bioassays in 2D culture revealed that acute treatment with post-exercise serum activated mTORC1 and ERK1/2. In conclusion, the post-exercise biochemical milieu, but not recombinant GH, enhances collagen content and tensile strength of engineered ligaments, in association with mTORC1 and ERK1/2 activation. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Transient performance simulation of aircraft engine integrated with fuel and control systems

International Nuclear Information System (INIS)

Wang, C.; Li, Y.G.; Yang, B.Y.

2017-01-01

Highlights: • A new performance simulation method for engine hydraulic fuel systems is introduced. • Time delay of engine performance due to fuel system model is noticeable but small. • The method provides details of fuel system behavior in engine transient processes. • The method could be used to support engine and fuel system designs. - Abstract: A new method for the simulation of gas turbine fuel systems based on an inter-component volume method has been developed. It is able to simulate the performance of each of the hydraulic components of a fuel system using physics-based models, which potentially offers more accurate results compared with those using transfer functions. A transient performance simulation system has been set up for gas turbine engines based on an inter-component volume (ICV) method. A proportional-integral (PI) control strategy is used for the simulation of engine controller. An integrated engine and its control and hydraulic fuel systems has been set up to investigate their coupling effect during engine transient processes. The developed simulation system has been applied to a model aero engine. The results show that the delay of the engine transient response due to the inclusion of the fuel system model is noticeable although relatively small. The developed method is generic and can be applied to any other gas turbines and their control and fuel systems.

Helicopter Gas Turbine Engine Performance Analysis : A Multivariable Approach

NARCIS (Netherlands)

Arush, Ilan; Pavel, M.D.

2017-01-01

Helicopter performance relies heavily on the available output power of the engine(s) installed. A simplistic single-variable analysis approach is often used within the flight-testing community to reduce raw flight-test data in order to predict the available output power under different atmospheric

Comparative performance analysis of combined-cycle pulse detonation turbofan engines (PDTEs

Directory of Open Access Journals (Sweden)

Sudip Bhattrai

2013-09-01

Full Text Available Combined-cycle pulse detonation engines are promising contenders for hypersonic propulsion systems. In the present study, design and propulsive performance analysis of combined-cycle pulse detonation turbofan engines (PDTEs is presented. Analysis is done with respect to Mach number at two consecutive modes of operation: (1 Combined-cycle PDTE using a pulse detonation afterburner mode (PDA-mode and (2 combined-cycle PDTE in pulse detonation ramjet engine mode (PDRE-mode. The performance of combined-cycle PDTEs is compared with baseline afterburning turbofan and ramjet engines. The comparison of afterburning modes is done for Mach numbers from 0 to 3 at 15.24 km altitude conditions, while that of pulse detonation ramjet engine (PDRE is done for Mach 1.5 to Mach 6 at 18.3 km altitude conditions. The analysis shows that the propulsive performance of a turbine engine can be greatly improved by replacing the conventional afterburner with a pulse detonation afterburner (PDA. The PDRE also outperforms its ramjet counterpart at all flight conditions considered herein. The gains obtained are outstanding for both the combined-cycle PDTE modes compared to baseline turbofan and ramjet engines.

Performance Enhancement by Brain Stimulation

Directory of Open Access Journals (Sweden)

Parisa Gazerani

2017-09-01

Full Text Available Number of substances and strategies are available to increase performance in sport (Catlin and Murray, 1996. Since 2004, the World Anti-Doping Agency (WADA posts an updated list of substances and methods prohibited to athletes. Drugs (e.g., steroids, stimulants are a major part of this list; however, technologies and methods (e.g., gene doping are increasingly being identified and added (WADA, 2017. Among technologies and methods that might exert a potential effect on athletic performance, brain stimulation has recently been subjected to extensive discussion. Neuro-enhancement for doping purposes has been termed “neurodoping” in the literature (Davis, 2013; however, this concept needs further documentation before the term “neurodoping” can be used properly. Two major non-invasive techniques of brain stimulations are transcranial magnetic stimulation (TMS (Hallett, 2007; Rossi et al., 2009, and transcranial direct current stimulation (tDCS (Stagg and Nitsche, 2011. In TMS, an electric coil held over the head applies magnetic pulses to create currents in the brain. In tDCS, a low, continuous electrical current is delivered to the brain by using surface electrodes attached on the scalp. TMS and tDCS have been used in both research and clinic (Shin and Pelled, 2017 for example to examine alterations in cognitive function or motor skills or to assist in recovering motor function after a stroke (Gomez Palacio Schjetnan et al., 2013 or reducing fatigue in patients with multiple sclerosis (Saiote et al., 2014. In an opinion paper, it was proposed that use of emerging brain stimulation techniques might also enhance physical and mental performance in sports (Davis, 2013. The assumption was based on several reports. For example some studies have shown that TMS could shorten reaction times to visual, auditory and touch stimuli, reduce tremor, and enhance the acquisition of complex motor skills. Based on the current evidence, a recent review (Colzato

An engineering evaluation of the Space Shuttle OMS engine after 5 orbital flights

Science.gov (United States)

David, D.

1983-01-01

Design features, performances on the first five flights, and condition of the Shuttle OMS engines are summarized. The engines were designed to provide a vacuum-fed 6000 lb of thrust and a 310 sec specific impulse, fueled by a combination of N2O4 and monomethylhydrazine (MMH) at a mixture ratio of 1.65. The design lifetime is 1000 starts and 15 hr of cumulative firing duration. The engine assembly is throat gimballed and features yaw actuators. No degradation of the hot components was observed during the first five flights, and the injector pattern maintained a uniform, enduring level of performance. An increase in the take-off loads have led to enhancing the wall thickness in the nozzle in affected areas. The engine is concluded to be performing to design specifications and is considered an operational system.

Simulating Effects of High Angle of Attack on Turbofan Engine Performance

Science.gov (United States)

Liu, Yuan; Claus, Russell W.; Litt, Jonathan S.; Guo, Ten-Huei

2013-01-01

A method of investigating the effects of high angle of attack (AOA) flight on turbofan engine performance is presented. The methodology involves combining a suite of diverse simulation tools. Three-dimensional, steady-state computational fluid dynamics (CFD) software is used to model the change in performance of a commercial aircraft-type inlet and fan geometry due to various levels of AOA. Parallel compressor theory is then applied to assimilate the CFD data with a zero-dimensional, nonlinear, dynamic turbofan engine model. The combined model shows that high AOA operation degrades fan performance and, thus, negatively impacts compressor stability margins and engine thrust. In addition, the engine response to high AOA conditions is shown to be highly dependent upon the type of control system employed.

Effects of Reynold's number on flight performance of turbofan engine

Energy Technology Data Exchange (ETDEWEB)

Kozu, Masao; Yajima, Satoshi [Defense Agency Tokyo (Japan); Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan))

1988-12-10

Concerning the performance of the F3-30 turbofan engine which is carried on the intermediate trainer XT-4 of the Air Self Defense Force, tests simulating its flight conditions were conducted at the Altitude Test Facility (ATF) of the Arnold Engineering Development Center (AEDC), U.S. Air Force in order to adjust the effect of Reynold's number corresponding to the flight condition. This report summarizes the results of the above tests. As the results of the tests, it was revealed that in order to calculate with precision the flight performance of the F3-30 turbofan engine, it was required to adjust Reynold's number against the following figures, namely the fan air flow, compressor air flow, compressor adiabatic efficiency, low pressure turbine gas flow and low pressure turbine adiabatic efficiency. The engine performance calculated by using the above adjustments agreed well with the measured values of the ATF tests. 7 refs., 17 figs., 1 tab.

Engineered band structure for an enhanced performance on quantum dot-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Jin, Bin Bin [Key Laboratory of Macromolecular Science of Shaanxi Province and School of Materials Science and Engineering, Shaanxi Normal University, Xi' an 710062 (China); Department of Chemical Engineering, Institute of Chemical Industry, Shaanxi Institute of Technology, Xi' an 710300 (China); Wang, Ye Feng [School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi' an 710062 (China); Wei, Dong; Chen, Yu; Zeng, Jing Hui, E-mail: jhzeng@ustc.edu [Key Laboratory of Macromolecular Science of Shaanxi Province and School of Materials Science and Engineering, Shaanxi Normal University, Xi' an 710062 (China); Cui, Bin [School of Chemistry and Materials Science, Northwestern University, Xi' an 710620 (China)

2016-06-20

A photon-to-current efficiency of 2.93% is received for the Mn-doped CdS (MCdS)-quantum dot sensitized solar cells (QDSSCs) using Mn:ZnO (MZnO) nanowire as photoanode. Hydrothermal synthesized MZnO are spin-coated on fluorine doped tin oxide (FTO) glass with P25 paste to serve as photoanode after calcinations. MCdS was deposited on the MZnO film by the successive ionic layer adsorption and reaction method. The long lived excitation energy state of Mn{sup 2+} is located inside the conduction band in the wide bandgap ZnO and under the conduction band of CdS, which increases the energetic overlap of donor and acceptor states, reducing the “loss-in-potential,” inhibiting charge recombination, and accelerating electron injection. The engineered band structure is well reflected by the electrochemical band detected using cyclic voltammetry. Cell performances are evidenced by current density-voltage (J-V) traces, diffuse reflectance spectra, transient PL spectroscopy, and incident photon to current conversion efficiency characterizations. Further coating of CdSe on MZnO/MCdS electrode expands the light absorption band of the sensitizer, an efficiency of 4.94% is received for QDSSCs.

A Framework for Performing V&V within Reuse-Based Software Engineering

Science.gov (United States)

Addy, Edward A.

1996-01-01

Verification and validation (V&V) is performed during application development for many systems, especially safety-critical and mission-critical systems. The V&V process is intended to discover errors, especially errors related to critical processing, as early as possible during the development process. Early discovery is important in order to minimize the cost and other impacts of correcting these errors. In order to provide early detection of errors, V&V is conducted in parallel with system development, often beginning with the concept phase. In reuse-based software engineering, however, decisions on the requirements, design and even implementation of domain assets can be made prior to beginning development of a specific system. In this case, V&V must be performed during domain engineering in order to have an impact on system development. This paper describes a framework for performing V&V within architecture-centric, reuse-based software engineering. This framework includes the activities of traditional application-level V&V, and extends these activities into domain engineering and into the transition between domain engineering and application engineering. The framework includes descriptions of the types of activities to be performed during each of the life-cycle phases, and provides motivation for the activities.

Experience with performance based training of nuclear criticality safety engineers

International Nuclear Information System (INIS)

Taylor, R.G.

1993-01-01

For non-reactor nuclear facilities, the U.S. Department of Energy (DOE) does not require that nuclear criticality safety engineers demonstrate qualification for their job. It is likely, however, that more formalism will be required in the future. Current DOE requirements for those positions which do have to demonstrate qualification indicate that qualification should be achieved by using a systematic approach such as performance based training (PBT). Assuming that PBT would be an acceptable mechanism for nuclear criticality safety engineer training in a more formal environment, a site-specific analysis of the nuclear criticality safety engineer job was performed. Based on this analysis, classes are being developed and delivered to a target audience of newer nuclear criticality safety engineers. Because current interest is in developing training for selected aspects of the nuclear criticality safety engineer job, the analysis is incompletely developed in some areas

Performance analysis and dynamic modeling of a single-spool turbojet engine

Science.gov (United States)

Andrei, Irina-Carmen; Toader, Adrian; Stroe, Gabriela; Frunzulica, Florin

2017-01-01

The purposes of modeling and simulation of a turbojet engine are the steady state analysis and transient analysis. From the steady state analysis, which consists in the investigation of the operating, equilibrium regimes and it is based on appropriate modeling describing the operation of a turbojet engine at design and off-design regimes, results the performance analysis, concluded by the engine's operational maps (i.e. the altitude map, velocity map and speed map) and the engine's universal map. The mathematical model that allows the calculation of the design and off-design performances, in case of a single spool turbojet is detailed. An in house code was developed, its calibration was done for the J85 turbojet engine as the test case. The dynamic modeling of the turbojet engine is obtained from the energy balance equations for compressor, combustor and turbine, as the engine's main parts. The transient analysis, which is based on appropriate modeling of engine and its main parts, expresses the dynamic behavior of the turbojet engine, and further, provides details regarding the engine's control. The aim of the dynamic analysis is to determine a control program for the turbojet, based on the results provided by performance analysis. In case of the single-spool turbojet engine, with fixed nozzle geometry, the thrust is controlled by one parameter, which is the fuel flow rate. The design and management of the aircraft engine controls are based on the results of the transient analysis. The construction of the design model is complex, since it is based on both steady-state and transient analysis, further allowing the flight path cycle analysis and optimizations. This paper presents numerical simulations for a single-spool turbojet engine (J85 as test case), with appropriate modeling for steady-state and dynamic analysis.

Performance test of remote controlled engineering vehicle system for CBRN threat. Countermeasure performance for CBRN-environment

International Nuclear Information System (INIS)

Naruse, Masahiro; Uemura, Keisuke; Morishita, Masahiro

2015-01-01

A research of 'remote controlled engineering vehicle system for CBRN threat' was triggered by the nuclear accident that successively happened after the Great East Japan Earthquake. This project focuses on the remote controlled engineering system that can be used for multi purposes such as debris/obstacle clearing operation or various reconnaissance operation, under CBRN threat. For the remote-controlled engineering vehicle, we conducted a series of validation tests for countermeasure performance for CBRN-environment. As a result, it is proved that the vehicle possess required performances for CBRN threat. (author)

Enhanced Discrete-Time Scheduler Engine for MBMS E-UMTS System Level Simulator

DEFF Research Database (Denmark)

Pratas, Nuno; Rodrigues, António

2007-01-01

In this paper the design of an E-UMTS system level simulator developed for the study of optimization methods for the MBMS is presented. The simulator uses a discrete event based philosophy, which captures the dynamic behavior of the Radio Network System. This dynamic behavior includes the user...... mobility, radio interfaces and the Radio Access Network. Its given emphasis on the enhancements developed for the simulator core, the Event Scheduler Engine. Two implementations for the Event Scheduler Engine are proposed, one optimized for single core processors and other for multi-core ones....

Comparative engine performance and emission analysis of CNG and gasoline in a retrofitted car engine

International Nuclear Information System (INIS)

Jahirul, M.I.; Masjuki, H.H.; Saidur, R.; Kalam, M.A.; Jayed, M.H.; Wazed, M.A.

2010-01-01

A comparative analysis is being performed of the engine performance and exhaust emission on a gasoline and compressed natural gas (CNG) fueled retrofitted spark ignition car engine. A new 1.6 L, 4-cylinder petrol engine was converted to the computer incorporated bi-fuel system which operated with either gasoline or CNG using an electronically controlled solenoid actuated valve mechanism. The engine brake power, brake specific fuel consumption, brake thermal efficiency, exhaust gas temperature and exhaust emissions (unburnt hydrocarbon, carbon mono-oxide, oxygen and carbon dioxides) were measured over a range of speed variations at 50% and 80% throttle positions through a computer based data acquisition and control system. Comparative analysis of the experimental results showed 19.25% and 10.86% reduction in brake power and 15.96% and 14.68% reduction in brake specific fuel consumption (BSFC) at 50% and 80% throttle positions respectively while the engine was fueled with CNG compared to that with the gasoline. Whereas, the retrofitted engine produced 1.6% higher brake thermal efficiency and 24.21% higher exhaust gas temperature at 80% throttle had produced an average of 40.84% higher NO x emission over the speed range of 1500-5500 rpm at 80% throttle. Other emission contents (unburnt HC, CO, O 2 and CO 2 ) were significantly lower than those of the gasoline emissions.

Experimental study of DI diesel engine performance using biodiesel blends with kerosene

Energy Technology Data Exchange (ETDEWEB)

Azad, A.K.; Ameer Uddin, S.M.; Alam, M.M. [Department of Mechanical Engineering, Bangladesh University of Engineering and Technology, Dhaka-1000 (Bangladesh)

2013-07-01

The experimental investigation offers a comprehensive study of DI diesel engine performance using bio-diesel from mustard oil blends with kerosene. The vegetable oil without trans-esterification reaction have been blended with kerosene oil by volume in some percentage like 20%, 30%, 40% and 50% which have been named as M20 (20% mustard, 80% kerosene), M30 (30% mustard, 70% kerosene), M40 (40% mustard, 60% kerosene) and M50 (50% mustard, 50% kerosene). The properties of the bio-fuel blended with kerosene have been tested in the laboratories with maintaining different ASTM standards. Then a four stroke, single cylinder, direct injection diesel engine has been mounted on the dynamometer bed for testing the performance of the engine using the bio-diesel blends. Several engine parameters like bsfc, bhp, break mean effective pressure, exhaust gas temperature, lube oil temperature, sound level etc. have been determined. A comparison has been made for engine performance of different bio-diesel blends with kerosene with the engine performance of diesel fuel.

An analytical and experimental study of performance on jatropha biodiesel engine

Directory of Open Access Journals (Sweden)

Ganapathy Thirunavukkarasu

2009-01-01

Full Text Available Biodiesel plays a major role as one of the alternative fuel options in direct injection diesel engines for more than a decade. Though many feed stocks are employed for making biodiesel worldwide, biodiesel derived from domestically available non-edible feed stocks such as Jatropha curcas L. is the most promising alternative engine fuel option especially in developing countries. Since experimental analysis of the engine is pricey as well as more time consuming and laborious, a theoretical thermodynamic model is necessary to analyze the performance characteristics of jatropha biodiesel fueled diesel engine. There were many experimental studies of jatropha biodiesel fueled diesel engine reported in the literature, yet theoretical study of this biodiesel run diesel engine is scarce. This work presents a theoretical thermodynamic study of single cylinder four stroke direct injection diesel engine fueled with biodiesel derived from jatropha oil. The two zone thermodynamic model developed in the present study computes the in-cylinder pressure and temperature histories in addition to various performance parameters. The results of the model are validated with experimental values for a reasonable agreement. The variation of cylinder pressure with crank angle for various models are also compared and presented. The effects of injection timing, relative air fuel ratio and compression ratio on the engine performance characteristics for diesel and jatropha biodiesel fuels are then investigated and presented in the paper.

Determining the optimum conditions for modified diesel fuel combustion considering its emission, properties and engine performance

International Nuclear Information System (INIS)

Fayyazbakhsh, Ahmad; Pirouzfar, Vahid

2016-01-01

Highlights: • Gas emissions, fuel properties and performance engine modeling. • Optimization of new modified fuel prepared from n-Butanol and Nano particles. • Model accuracy analysis. - Abstract: This essay scrutinizes an experimental study conducted to appraise the influence of using n-Butanol with diesel fuel in 5% and 10% (volume) n-Butanol, 1% nitro methane (NM), injection timing and two Nano-particles (alumina and a type of silica powder) on the engine performance (brake specific fuel consumption and engine power), fuel properties (Cetane number and flash point) and exhaust emissions (soot, NO_x and CO) of an engine with 4-cylinder (with a system of common rail fuel injection), intercooling, cooled exhaust gas recirculation (EGR), and turbocharged. The tests are conducted by varying the engine load (25 and 75 nm) and changing engine speed (1500 and 2200 rpm). Normal Butanol presents better brake specific fuel consumption (BSFC) but this blend doesn’t reflect better engine power. All the percentages of n-Butanol in the fuel make Cetane number decrease but adding 1% of nitro methane makes Cetane number increase. For all the n-Butanol, the percentage flash makes the fuel decrease in comparison to pure diesel fuel. The current experimental study demonstrates that adding the n-Butanol and nitro methane to diesel fuel direct into diminishing soot emission. In contrast, this blend raises NO_x and CO emissions. Furthermore, this research indicates that the increase of engine speed dwindle air pollutants and enhances BSFC. It also remarks that power gets increased at low engine speed. However, power gets reducedat high speed. This article represents that the increasing of engine load leads to increasing all of air pollutant, increasing of power and decreasing of brake specific fuel consumption. Both the Cetane number and flash point are independent from engine speed and engine load. The present paper shows that the effect of silica with high percentage of n

A combined noise reduction and torque enhancement system for an I. C. engine

Energy Technology Data Exchange (ETDEWEB)

Hutchins, S.M.; Stothers, Ian; McDougall, N.M.

1993-02-10

The present invention provides a combined noise reduction and torque enhancement system for an internal combustion engine. It comprises means for periodically constricting or occluding the exhaust and/or inlet at least one frequency related to the rotation frequency of the engine. In a preferred embodiment of the invention, the constriction means comprises a plug member arranged to be oscillated in an aperture along the axis of flow of gas in the exhaust and/or inlet. (author)

Optimal Tuner Selection for Kalman-Filter-Based Aircraft Engine Performance Estimation

Science.gov (United States)

Simon, Donald L.; Garg, Sanjay

2011-01-01

An emerging approach in the field of aircraft engine controls and system health management is the inclusion of real-time, onboard models for the inflight estimation of engine performance variations. This technology, typically based on Kalman-filter concepts, enables the estimation of unmeasured engine performance parameters that can be directly utilized by controls, prognostics, and health-management applications. A challenge that complicates this practice is the fact that an aircraft engine s performance is affected by its level of degradation, generally described in terms of unmeasurable health parameters such as efficiencies and flow capacities related to each major engine module. Through Kalman-filter-based estimation techniques, the level of engine performance degradation can be estimated, given that there are at least as many sensors as health parameters to be estimated. However, in an aircraft engine, the number of sensors available is typically less than the number of health parameters, presenting an under-determined estimation problem. A common approach to address this shortcoming is to estimate a subset of the health parameters, referred to as model tuning parameters. The problem/objective is to optimally select the model tuning parameters to minimize Kalman-filterbased estimation error. A tuner selection technique has been developed that specifically addresses the under-determined estimation problem, where there are more unknown parameters than available sensor measurements. A systematic approach is applied to produce a model tuning parameter vector of appropriate dimension to enable estimation by a Kalman filter, while minimizing the estimation error in the parameters of interest. Tuning parameter selection is performed using a multi-variable iterative search routine that seeks to minimize the theoretical mean-squared estimation error of the Kalman filter. This approach can significantly reduce the error in onboard aircraft engine parameter estimation

Engineering of pectinolytic enzymes for enhanced thermostability

DEFF Research Database (Denmark)

Larsen, Dorte Møller

Conversion of waste materials into valuable compounds is promising concerning transformation of byproduct streams such as sugar beet and potato pulp. In order to obtain those compounds with reduced energy consumption, carbohydrate active enzymes can be used as catalysts. Sugar beet and potato pulp...... consist of pectin that can be converted into beneficial polymeric and oligomeric carbohydrates requiring enzymes such as pectin lyases, rhamnogalacturonan I (RGI) lyases, polygalacturonases and galactanases. Enzymatic conversion of such pectinaceous biomasses at high temperatures is advantageous...... as it gives rise to lower substrate viscosity, easier mixing, higher substrate solubility and lowers the risk of contamination. The overall objective of this thesis was to discover enzymes for degradation of RGI structures in pectin and further engineer for enhanced thermostability. The hypotheses were...

Study on Combustion Performance of Diesel Engine Fueled by Synthesized Waste Cooking Oil Biodiesel Blends

Directory of Open Access Journals (Sweden)

Duraid F. Maki

2018-02-01

Full Text Available The waste cooking oil or used cooking oil is the best source of biodiesel synthesizing because it enters into the so-called W2E field whereas not only get rid of the used cooking oils but produce energy from waste fuel. In this study, biodiesel was synthesized from the used cooking oil and specifications are tested. From 1 liter of used cooking oil, 940 ml is gained. The remaining of liter is glycerin and water. Blend of 20% of biodiesel with 80% of net diesel by volume is formed. Blends of 100% diesel and 100% biodiesel are prepared too. The diesel engine combustion performance is studied. Brake thermal efficiency, brake specific fuel consumption, volumetric efficiency, mean effective pressure, and engine outlet temperature. Cylinder pressure variation with crank angle is analyzed. At last not least, the concentrations of hydro carbon and nitrogen pollutants are measured. The results showed significant enhancement in engine power and pollutant gases emitted. There is positive compatible with other critical researches.

Performance of a RBCC Engine in Rocket-Operation

Science.gov (United States)

Tomioka, Sadatake; Kubo, Takahiro; Noboru Sakuranaka; Tani, Koichiro

Combination of a scramjet (supersonic combustion ramjet) flow-pass with embedded rocket engines (the combined system termed as Rocket-based Combined Cycle engine) are expected to be the most effective propulsion system for space launch vehicles. Either SSTO (Single Stage To Orbit) system or TSTO (Two Stage To Orbit) system with separation at high altitude needs final stage acceleration in space, so that the RBCC (Rocket Based Combined Cycle) engine should be operated as rocket engines. Performance of the scramjet combustor as the extension to the rocket nozzle, was experimentally evaluated by injecting inert gas at various pressure through the embedded rocket chamber while the whole sub-scaled model was placed in a low pressure chamber connected to an air-driven ejector system. The results showed that the thrust coefficient was about 1.2, the low value being found to mainly due to the friction force on the scramjet combustor wall, while blocking the scramjet flow pass’s opening to increase nozzle extension thrust surface, was found to have little effects on the thrust performance. The combustor was shortened to reduce the friction loss, however, degree of reduction was limited as friction decreased rapidly with distance from the onset of the scramjet combustor.

Gene doping: a review of performance-enhancing genetics.

Science.gov (United States)

Gaffney, Gary R; Parisotto, Robin

2007-08-01

Unethical athletes and their mentors have long arrogated scientific and medical advances to enhance athletic performance, thus gaining a dishonest competitive advantage. Building on advances in genetics, a new threat arises from athletes using gene therapy techniques in the same manner that some abused performance-enhancing drugs were used. Gene doping, as this is known, may produce spectacular physiologic alterations to dramatically enhance athletic abilities or physical appearance. Furthermore, gene doping may present pernicious problems for the regulatory agencies and investigatory laboratories that are entrusted to keep sporting events fair and ethical. Performance-enhanced genetics will likewise present unique challenges to physicians in many spheres of their practice.

Enhanced productivity of simulation engineers

International Nuclear Information System (INIS)

Rohrmann, C.

1999-01-01

Simulation has always required a hybrid collection of individuals for software development and maintenance, half engineers and half computer scientists. This paper presents a chronology and an indication of some of the technology currently available to simplify simulation software development and maintenance so that engineers can truly be engineers and not computer scientists. (author)

IMPLEMENTATION OF TECHNOLOGY ENHANCED LEARNING PEDAGOGY AND IMPACT ON EMPLOYABILITY AND LEARNING WITHIN ENGINEERING EDUCATION FRAMEWORKS

OpenAIRE

Vickerstaff, Rebecca

2015-01-01

Engineering Education experiences turbulent changes, both from government pressures and from industry demands on readdressing the requirements of graduate capability. Despite vast amounts of engineering literature discussing ‘change’ within the field, engineering curricula still maintains its predominant pedagogic model of dissemination to students as it did in previous decades. Technology Enhanced Learning in education has created new and flexible options in the delivery and assessmen...

Effects of gaseous ammonia direct injection on performance characteristics of a spark-ignition engine

International Nuclear Information System (INIS)

Ryu, Kyunghyun; Zacharakis-Jutz, George E.; Kong, Song-Charng

2014-01-01

Highlights: • This is the very first study in utilizing direct injection of gaseous ammonia in an SI engine. • Engine combustion using direct injection of gaseous ammonia is proven feasible. • Energy efficiency using ammonia is comparable to that using gasoline. • CO emissions are decreased but emissions of NOx and HC are increased when ammonia is used. - Abstract: The effects of direct injection of gaseous ammonia on the combustion characteristics and exhaust emissions of a spark-ignition engine were investigated. Port-injection gasoline was used to enhance the burning of ammonia that was directly injected into the engine cylinder. Appropriate direct injection strategies were developed to allow ammonia to be used in spark-ignition engines without sacrifice of volumetric efficiency. Experimental results show that with gasoline providing the baseline power of 0.6 kW, total engine power could increase to 2.7 kW when the injection timing of ammonia was advanced to 370 BTDC with injection duration of 22 ms. Engine performance with use of gasoline–ammonia was compared to that with gasoline alone. For operations using gasoline–ammonia, with baseline power from gasoline at 0.6 kW the appropriate ammonia injection timing was found to range from 320 to 370 BTDC for producing 1.5–2.7 kW. The peak pressures were slightly lower than those using gasoline alone because of the lower flame of ammonia, resulting in reduction of cylinder pressure. The brake specific energy consumption (BSEC) with gasoline–ammonia was very similar to that with gasoline alone. Ammonia direct injection caused slight reductions of BSCO for all the loads studied but significantly increased BSHC because of the reduced combustion temperature of ammonia combustion. The use of ammonia resulted in increased NOx emissions because of formation of fuel NOx. Ammonia slip was also detected in the engine exhaust because of incomplete combustion

Catalyst engineering for lithium ion batteries: the catalytic role of Ge in enhancing the electrochemical performance of SnO2(GeO2)0.13/G anodes.

Science.gov (United States)

Zhu, Yun Guang; Wang, Ye; Han, Zhao Jun; Shi, Yumeng; Wong, Jen It; Huang, Zhi Xiang; Ostrikov, Kostya Ken; Yang, Hui Ying

2014-12-21

The catalytic role of germanium (Ge) was investigated to improve the electrochemical performance of tin dioxide grown on graphene (SnO(2)/G) nanocomposites as an anode material of lithium ion batteries (LIBs). Germanium dioxide (GeO(20) and SnO(2) nanoparticles (GeO(2))0.13/G nanocomposites can deliver a capacity of 1200 mA h g(-1) at a current density of 100 mA g(-1), which is much higher than the traditional theoretical specific capacity of such nanocomposites (∼ 702 mA h g(-1)). More importantly, the SnO(2)(GeO(2))0.13/G nanocomposites exhibited an improved rate, large current capability (885 mA h g(-1) at a discharge current of 2000 mA g(-1)) and excellent long cycling stability (almost 100% retention after 600 cycles). The enhanced electrochemical performance was attributed to the catalytic effect of Ge, which enabled the reversible reaction of metals (Sn and Ge) to metals oxide (SnO(2) and GeO(2)) during the charge/discharge processes. Our demonstrated approach towards nanocomposite catalyst engineering opens new avenues for next-generation high-performance rechargeable Li-ion batteries anode materials.

Data Fusion for Enhanced Aircraft Engine Prognostics and Health Management

Science.gov (United States)

Volponi, Al

2005-01-01

Aircraft gas-turbine engine data is available from a variety of sources, including on-board sensor measurements, maintenance histories, and component models. An ultimate goal of Propulsion Health Management (PHM) is to maximize the amount of meaningful information that can be extracted from disparate data sources to obtain comprehensive diagnostic and prognostic knowledge regarding the health of the engine. Data fusion is the integration of data or information from multiple sources for the achievement of improved accuracy and more specific inferences than can be obtained from the use of a single sensor alone. The basic tenet underlying the data/ information fusion concept is to leverage all available information to enhance diagnostic visibility, increase diagnostic reliability and reduce the number of diagnostic false alarms. This report describes a basic PHM data fusion architecture being developed in alignment with the NASA C-17 PHM Flight Test program. The challenge of how to maximize the meaningful information extracted from disparate data sources to obtain enhanced diagnostic and prognostic information regarding the health and condition of the engine is the primary goal of this endeavor. To address this challenge, NASA Glenn Research Center, NASA Dryden Flight Research Center, and Pratt & Whitney have formed a team with several small innovative technology companies to plan and conduct a research project in the area of data fusion, as it applies to PHM. Methodologies being developed and evaluated have been drawn from a wide range of areas including artificial intelligence, pattern recognition, statistical estimation, and fuzzy logic. This report will provide a chronology and summary of the work accomplished under this research contract.

Dissecting engineered cell types and enhancing cell fate conversion via CellNet

Science.gov (United States)

Morris, Samantha A.; Cahan, Patrick; Li, Hu; Zhao, Anna M.; San Roman, Adrianna K.; Shivdasani, Ramesh A.; Collins, James J.; Daley, George Q.

2014-01-01

SUMMARY Engineering clinically relevant cells in vitro holds promise for regenerative medicine, but most protocols fail to faithfully recapitulate target cell properties. To address this, we developed CellNet, a network biology platform that determines whether engineered cells are equivalent to their target tissues, diagnoses aberrant gene regulatory networks, and prioritizes candidate transcriptional regulators to enhance engineered conversions. Using CellNet, we improved B cell to macrophage conversion, transcriptionally and functionally, by knocking down predicted B cell regulators. Analyzing conversion of fibroblasts to induced hepatocytes (iHeps), CellNet revealed an unexpected intestinal program regulated by the master regulator Cdx2. We observed long-term functional engraftment of mouse colon by iHeps, thereby establishing their broader potential as endoderm progenitors and demonstrating direct conversion of fibroblasts into intestinal epithelium. Our studies illustrate how CellNet can be employed to improve direct conversion and to uncover unappreciated properties of engineered cells. PMID:25126792

Enhancing the antibacterial performance of orthopaedic implant materials by fibre laser surface engineering

Science.gov (United States)

Chan, Chi-Wai; Carson, Louise; Smith, Graham C.; Morelli, Alessio; Lee, Seunghwan

2017-05-01

Implant failure caused by bacterial infection is extremely difficult to treat and usually requires the removal of the infected components. Despite the severe consequence of bacterial infection, research into bacterial infection of orthopaedic implants is still at an early stage compared to the effort on enhancing osseointegration, wear and corrosion resistance of implant materials. In this study, the effects of laser surface treatment on enhancing the antibacterial properties of commercially pure (CP) Ti (Grade 2), Ti6Al4V (Grade 5) and CoCrMo alloy implant materials were studied and compared for the first time. Laser surface treatment was performed by a continuous wave (CW) fibre laser with a near-infrared wavelength of 1064 nm in a nitrogen-containing environment. Staphylococcus aureus, commonly implicated in infection associated with orthopaedic implants, was used to investigate the antibacterial properties of the laser-treated surfaces. The surface roughness and topography of the laser-treated materials were analysed by a 2D roughness testing and by AFM. The surface morphologies before and after 24 h of bacterial cell culture were captured by SEM, and bacterial viability was determined using live/dead staining. Surface chemistry was analysed by XPS and surface wettability was measured using the sessile drop method. The findings of this study indicated that the laser-treated CP Ti and Ti6Al4V surfaces exhibited a noticeable reduction in bacterial adhesion and possessed a bactericidal effect. Such properties were attributable to the combined effects of reduced hydrophobicity, thicker and stable oxide films and presence of laser-induced nano-features. No similar antibacterial effect was observed in the laser-treated CoCrMo.

Modified Thermoresponsive Hyperbranched Polymers for Improved Viscosity and Enhanced Lubricity of Engine Oils

Energy Technology Data Exchange (ETDEWEB)

Cosimbescu, Lelia [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Robinson, Joshua W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bays, John Timothy [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Qu, Jun [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); West, Brian [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-09-30

The manuscript captures the chronological succession of the molecular design progression through multiple architectures and topologies of the polymeric viscosity index improvers and their rheology bench test performance. Tribology testing was also performed on selected analogs and their friction and wear was evaluated. Finally, a top performing polymer was selected for engine testing, scaled-up, and its rheological performance in a complete formulation was assessed. The engine performance of the viscosity index improver was examined against an industry-established baseline.

FACTORS AFFECTING PERFORMANCE OF ENGINEERED BARRIERS

International Nuclear Information System (INIS)

J.A. BLINK, R.W. ANDREWS, J.N. BAILEY, T.W. DOERING J.H. LEE, J.K. MCCOY, D.G. MCKENZIE, D. SEVOUGIAN AND V. VALLIKAT

1998-01-01

For the Yucca Mountain Viability Assessment (VA), a reference design was tentatively selected in September 1997, and a series of model abstractions are being prepared for the performance assessment (PA) of that design. To determine the sensitivity of peak dose rate at the accessible environment to engineered components, several design options were subjected to the PA models available late in FY97

Performance of small-scale aero-derivative industrial gas turbines derived from helicopter engines

Directory of Open Access Journals (Sweden)

Barinyima Nkoi

2013-12-01

Full Text Available This paper considers comparative assessment of simple and advanced cycle small-scale aero-derivative industrial gas turbines derived from helicopter engines. More particularly, investigation was made of technical performance of the small-scale aero-derivative engine cycles based on existing and projected cycles for applications in industrial power generation, combined heat and power concept, rotating equipment driving, and/or allied processes. The investigation was done by carrying out preliminary design and performance simulation of a simple cycle (baseline two-spool small-scale aero-derivative turboshaft engine model, and some advanced counterpart aero-derivative configurations. The advanced configurations consist of recuperated and intercooled/recuperated engine cycles of same nominal power rating of 1.567 MW. The baseline model was derived from the conversion of an existing helicopter engine model. In doing so, design point and off-design point performances of the engine models were established. In comparing their performances, it was observed that to a large extent, the advanced engine cycles showed superior performance in terms of thermal efficiency, and specific fuel consumption. In numerical terms, thermal efficiencies of recuperated engine cycle, and intercooled/recuperated engine cycles, over the simple cycle at DP increased by 13.5%, and 14.5% respectively, whereas specific fuel consumption of these cycles over simple cycle at DP decreased by 12.5%, and 13% respectively. This research relied on open access public literature for data.

Performance assessment of a Multi-fuel Hybrid Engine for Future Aircraft

NARCIS (Netherlands)

Yin, F.; Gangoli Rao, A.

2016-01-01

This paper presents performance assessment of the proposed hybrid engine concept using Liquid Natural Gas (LNG) and kerosene. The multi-fuel hybrid engine is a new engine concept integrated with contra rotating fans, sequential dual combustion chambers to facilitate “Energy Mix” in aviation and a

Performance assessment of a multi-fuel hybrid engine for future aircraft

NARCIS (Netherlands)

Yin, F.; Gangoli Rao, A.; Bhat, Abhishek; Chen, Min

2018-01-01

This paper presents the performance assessment of a novel turbofan engine using two energy sources: Liquid Natural Gas (LNG) and kerosene, called Multi-Fuel Hybrid Engine (MFHE). The MFHE is a new engine concept consisting of several novel features, such as a contra-rotating fan to sustain

Developing a system engineering program to improve performance and reliability

International Nuclear Information System (INIS)

Keuter, D.

1985-01-01

After several maintenance, operational, and equipment problems last year, Trojan set out on a mission to improve plant performance and reliability by strengthening its on-site engineering organization. This paper presents Trojan's plans in developing an on-site system engineering organization

Experimental investigation of the effects of direct water injection parameters on engine performance in a six-stroke engine

International Nuclear Information System (INIS)

Arabaci, Emre; İçingür, Yakup; Solmaz, Hamit; Uyumaz, Ahmet; Yilmaz, Emre

2015-01-01

Highlights: • Exhaust gas temperature and specific fuel consumption decreased with six stroke engine. • Thermal efficiency increased with water injection. • NO emissions decreased with water injection as the temperature decreased at the end of cycle. • Injection timing should be advanced with the increase of engine speed. • HC and CO emissions decrease until 3000 rpm engine speed. - Abstract: In this study, the effects of water injection quantity and injection timing were investigated on engine performance and exhaust emissions in a six-stroke engine. For this purpose, a single cylinder, four-stroke gasoline engine was converted to six-stroke engine modifying a new cam mechanism and adapting the water injection system. The experiments were conducted at stoichometric air/fuel ratio (λ = 1) between 2250 and 3500 rpm engine speed at full load with liquid petroleum gas. Water injection was performed at three different stages as before top dead center, top dead center and after top dead center at constant injection duration and four different injection pressure 25, 50, 75 and 100 bar. The test results showed that exhaust gas temperature and specific fuel consumption decreased by about 7% and 9% respectively. In contrast, fuel consumption and power output increased 2% and 10% respectively with water injection. Thermal efficiency increased by about 8.72% with water injection. CO and HC emissions decreased 21.97% and 18.23% until 3000 rpm respectively. NO emissions decreased with water injection as the temperature decreased at the end of cycle. As a result, it was seen that engine performance improved when suitable injection timing and injected water quantity were selected due to effect of exhaust heat recovery with water injection

Human Engineering Modeling and Performance Lab Study Project

Science.gov (United States)

Oliva-Buisson, Yvette J.

2014-01-01

The HEMAP (Human Engineering Modeling and Performance) Lab is a joint effort between the Industrial and Human Engineering group and the KAVE (Kennedy Advanced Visualiations Environment) group. The lab consists of sixteen camera system that is used to capture human motions and operational tasks, through te use of a Velcro suit equipped with sensors, and then simulate these tasks in an ergonomic software package know as Jac, The Jack software is able to identify the potential risk hazards.

On the assessment of performance and emissions characteristics of a SI engine provided with a laser ignition system

Science.gov (United States)

Birtas, A.; Boicea, N.; Draghici, F.; Chiriac, R.; Croitoru, G.; Dinca, M.; Dascalu, T.; Pavel, N.

2017-10-01

Performance and exhaust emissions of spark ignition engines are strongly dependent on the development of the combustion process. Controlling this process in order to improve the performance and to reduce emissions by ensuring rapid and robust combustion depends on how ignition stage is achieved. An ignition system that seems to be able for providing such an enhanced combustion process is that based on plasma generation using a Q-switched solid state laser that delivers pulses with high peak power (of MW-order level). The laser-spark devices used in the present investigations were realized using compact diffusion-bonded Nd:YAG/Cr4+:YAG ceramic media. The laser igniter was designed, integrated and built to resemble a classical spark plug and therefore it could be mounted directly on the cylinder head of a passenger car engine. In this study are reported the results obtained using such ignition system provided for a K7M 710 engine currently produced by Renault-Dacia, where the standard calibrations were changed towards the lean mixtures combustion zone. Results regarding the performance, the exhaust emissions and the combustion characteristics in optimized spark timing conditions, which demonstrate the potential of such an innovative ignition system, are presented.

Defect engineering of two-dimensional WO{sub 3} nanosheets for enhanced electrochromism and photoeletrochemical performance

Energy Technology Data Exchange (ETDEWEB)

Zhou, Xiaofang; Zheng, Xiaoli; Yan, Bo; Xu, Tao; Xu, Qun, E-mail: qunxu@zzu.edu.cn

2017-04-01

Highlights: • We establish a facile strategy by solvothermal reaction and hydrogenation to synthesize 2D WO{sub 3} ultrathin nanosheets with abundant oxygen vacancies. • We find that the hydrogenated WO{sub 3} ultrathin nanosheets exhibit outstanding electrochromism properties. • Moreover, the hydrogenated WO{sub 3} nanosheets also exhibit remarkable photocatalytic performance. • The outstanding electrochromism and photoelectrochemical performances are mainly due to increased oxygen vacancies and narrowed band gap. - Abstract: The capability of introduction of oxygen vacancies in a controlled way has emerged as the heart of modern transition metal oxide semiconductor chemistry. As chemical defects, the oxygen vacancies have been proposed as electron donors, which are prone to increase carrier density and promote charge carrier separation. Herein, we have successfully prepared 2D WO{sub 3} ultrathin nanosheets with abundant surface oxygen vacancies by a combination of facile solvothermal reaction and hydrogenation method. The resultant hydrogenated WO{sub 3} ultrathin nanosheets exhibit remarkable electrochromism and photocatalytic performances compared with the non-hydrogenated samples, mainly due to their increased oxygen vacancies, narrowed band gap coupled with fast charge transfer and enhanced adsorption of visible light.

Enhanced isoprenoid production from xylose by engineered Saccharomyces cerevisiae.

Science.gov (United States)

Kwak, Suryang; Kim, Soo Rin; Xu, Haiqing; Zhang, Guo-Chang; Lane, Stephan; Kim, Heejin; Jin, Yong-Su

2017-11-01

Saccharomyces cerevisiae has limited capabilities for producing fuels and chemicals derived from acetyl-CoA, such as isoprenoids, due to a rigid flux partition toward ethanol during glucose metabolism. Despite numerous efforts, xylose fermentation by engineered yeast harboring heterologous xylose metabolic pathways was not as efficient as glucose fermentation for producing ethanol. Therefore, we hypothesized that xylose metabolism by engineered yeast might be a better fit for producing non-ethanol metabolites. We indeed found that engineered S. cerevisiae on xylose showed higher expression levels of the enzymes involved in ethanol assimilation and cytosolic acetyl-CoA synthesis than on glucose. When genetic perturbations necessary for overproducing squalene and amorphadiene were introduced into engineered S. cerevisiae capable of fermenting xylose, we observed higher titers and yields of isoprenoids under xylose than glucose conditions. Specifically, co-overexpression of a truncated HMG1 (tHMG1) and ERG10 led to substantially higher squalene accumulation under xylose than glucose conditions. In contrast to glucose utilization producing massive amounts of ethanol regardless of aeration, xylose utilization allowed much less amounts of ethanol accumulation, indicating ethanol is simultaneously re-assimilated with xylose consumption and utilized for the biosynthesis of cytosolic acetyl-CoA. In addition, xylose utilization by engineered yeast with overexpression of tHMG1, ERG10, and ADS coding for amorphadiene synthase, and the down-regulation of ERG9 resulted in enhanced amorphadiene production as compared to glucose utilization. These results suggest that the problem of the rigid flux partition toward ethanol production in yeast during the production of isoprenoids and other acetyl-CoA derived chemicals can be bypassed by using xylose instead of glucose as a carbon source. Biotechnol. Bioeng. 2017;114: 2581-2591. © 2017 Wiley Periodicals, Inc. © 2017 Wiley

Flexible n-type thermoelectric composite films with enhanced performance through interface engineering and post-treatment

Science.gov (United States)

An, Hyeunhwan; Karas, Dale; Kim, Byung-Wook; Trabia, Sarah; Moon, Jaeyun

2018-07-01

Flexible thermoelectric (TE) materials, which are devices that convert thermal gradients to electrical energy, have attracted interest for practical energy-harvesting/recovery applications. However, as compared with p-type materials, the progress on the development of n-type TE flexible materials has been slow due to difficulties involved in n-type doping techniques. This study used high mobility carbon nanotubes (CNTs) to a uniformly mixed hybrid-composite, resulting in an enhanced power factor by increasing electrical conductivity. The energy filtering effect and stoichiometric composition of the material used, bismuth telluride (Bi2Te3) correlated to a significant enhancement in TE performance, with a power factor of 225.9 μW m‑1K‑2 at room temperature: a factor of 65 higher than as-fabricated composite film. This paper describes a simplified synthesis for the preparation of the composite film that eliminates time-intensive and cost-prohibitive processing, traditionally seen during extrusion and dicing inorganic manufacturing. The resulting post-annealed composite film consisting of Bi2Te3 nanowire and CNTs demonstrate a promising candidate for material that can be used for an n-type TE device that has improved energy conversion efficiency.

BPELPower—A BPEL execution engine for geospatial web services

Science.gov (United States)

Yu, Genong (Eugene); Zhao, Peisheng; Di, Liping; Chen, Aijun; Deng, Meixia; Bai, Yuqi

2012-10-01

The Business Process Execution Language (BPEL) has become a popular choice for orchestrating and executing workflows in the Web environment. As one special kind of scientific workflow, geospatial Web processing workflows are data-intensive, deal with complex structures in data and geographic features, and execute automatically with limited human intervention. To enable the proper execution and coordination of geospatial workflows, a specially enhanced BPEL execution engine is required. BPELPower was designed, developed, and implemented as a generic BPEL execution engine with enhancements for executing geospatial workflows. The enhancements are especially in its capabilities in handling Geography Markup Language (GML) and standard geospatial Web services, such as the Web Processing Service (WPS) and the Web Feature Service (WFS). BPELPower has been used in several demonstrations over the decade. Two scenarios were discussed in detail to demonstrate the capabilities of BPELPower. That study showed a standard-compliant, Web-based approach for properly supporting geospatial processing, with the only enhancement at the implementation level. Pattern-based evaluation and performance improvement of the engine are discussed: BPELPower directly supports 22 workflow control patterns and 17 workflow data patterns. In the future, the engine will be enhanced with high performance parallel processing and broad Web paradigms.

Model Engine Performance Measurement From Force Balance Instrumentation

Science.gov (United States)

Jeracki, Robert J.

1998-01-01

A large scale model representative of a low-noise, high bypass ratio turbofan engine was tested for acoustics and performance in the NASA Lewis 9- by 15-Foot Low-Speed Wind Tunnel. This test was part of NASA's continuing Advanced Subsonic Technology Noise Reduction Program. The low tip speed fan, nacelle, and an un-powered core passage (with core inlet guide vanes) were simulated. The fan blades and hub are mounted on a rotating thrust and torque balance. The nacelle, bypass duct stators, and core passage are attached to a six component force balance. The two balance forces, when corrected for internal pressure tares, measure the total thrust-minus-drag of the engine simulator. Corrected for scaling and other effects, it is basically the same force that the engine supports would feel, operating at similar conditions. A control volume is shown and discussed, identifying the various force components of the engine simulator thrust and definitions of net thrust. Several wind tunnel runs with nearly the same hardware installed are compared, to identify the repeatability of the measured thrust-minus-drag. Other wind tunnel runs, with hardware changes that affected fan performance, are compared to the baseline configuration, and the thrust and torque effects are shown. Finally, a thrust comparison between the force balance and nozzle gross thrust methods is shown, and both yield very similar results.

Dual-fuel natural gas/diesel engines: Technology, performance, and emissions

Science.gov (United States)

Turner, S. H.; Weaver, C. S.

1994-11-01

An investigation of current dual-fuel natural gas/diesel engine design, performance, and emissions was conducted. The most pressing technological problems associated with dual-fuel engine use were identified along with potential solutions. It was concluded that dual-fuel engines can achieve low NO(sub x) and particulate emissions while retaining fuel-efficiency and BMEP levels comparable to those of diesel engines. The investigation also examined the potential economic impact of dual-fuel engines in diesel-electric locomotives, marine vessels, farm equipment, construction, mining, and industrial equipment, and stand-alone electricity generation systems. Recommendations for further additional funding to support research, development, and demonstration in these applications were then presented.

Effect Of Compression Ratio On The Performance Of Diesel Engine At Different Loads.

OpenAIRE

Abhishek Reddy G; Nirmal Pratap Singh

2015-01-01

Variable compression ratio (VCR) technology has long been recognized as a method for improving the automobile engine performance, efficiency, fuel economy with reduced emission. The main feature of the VCR engine is to operate at different compression ratio, by changing the combustion chamber volume, depending on the vehicle performance needs .The need to improve the performance characteristics of the IC Engine has necessitated the present research. Increasing the compression rati...

Combination of traditional mutation and metabolic engineering to enhance ansamitocin P-3 production in Actinosynnema pretiosum.

Science.gov (United States)

Du, Zhi-Qiang; Zhang, Yuan; Qian, Zhi-Gang; Xiao, Han; Zhong, Jian-Jiang

2017-12-01

Ansamitocin P-3 (AP-3) is a maytansinoid with its most compelling antitumor activity, however, the low production titer of AP-3 greatly restricts its wide commercial application. In this work, a combinatorial approach including random mutation and metabolic engineering was conducted to enhance AP-3 biosynthesis in Actinosynnema pretiosum. First, a mutant strain M was isolated by N-methyl-N'-nitro-N-nitrosoguanidine mutation, which could produce AP-3 almost threefold that of wild type (WT) in 48 deep-well plates. Then, by overexpressing key biosynthetic genes asmUdpg and asm13-17 in the M strain, a further 60% increase of AP-3 production in 250-ml shake flasks was achieved in the engineered strain M-asmUdpg:asm13-17 compared to the M strain, and its maximum AP-3 production reached 582.7 mg/L, which is the highest as ever reported. Both the gene transcription levels and intracellular intermediate concentrations in AP-3 biosynthesis pathway were significantly increased in the M and M-asmUdpg:asm13-17 during fermentation compared to the WT. The good fermentation performance of the engineered strain was also confirmed in a lab-scale bioreactor. This work demonstrated that combination of random mutation and metabolic engineering could promote AP-3 biosynthesis and might be helpful for increasing the production of other industrially important secondary metabolites. © 2017 Wiley Periodicals, Inc.

Conventional vs. unconventional enhanced (or engineered) geothermal systems

Energy Technology Data Exchange (ETDEWEB)

Dzebisashvili, K.; Breede, K.; Liu, X.; Falcone, G. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). ITE

2013-08-01

Enhanced (or Engineered) Geothermal Systems (EGS) have evolved from the Hot Dry Rock (HDR) concept, implemented for the first time at Fenton Hill in 1977, and subsequently through the Stimulated Geothermal System, the Deep Heat Mining and finally the Deep Earth Geothermal. All of these systems usually imply petro-thermal processes. The term EGS has evolved to include conduction dominated, low permeability resources in sedimentary and basement formations, as well as geopressured, magma, and low-grade, unproductive hydrothermal resources. Co-produced hot water from hydrocarbon wells has also been included by some in the definition of EGS, which constitutes a considerable divergence from the original concept. Four decades on from the first EGS implementation, this paper highlights the lessons learned from 'conventional' systems and contrasts the 'unconventional' solutions that have been proposed. Examples of unconventional EGS include single-well solutions, downhole heat exchangers, engineered well profiles and using circulation fluids other than water. Perhaps some of the ideas proposed in the past, which would be considered unconventional, have remained dormant or never made it to a commercial stage for field implementation, but they may yet open doors to the future generations of EGS. (orig.)

Performance Engineering Research Institute SciDAC-2 Enabling Technologies Institute Final Report

Energy Technology Data Exchange (ETDEWEB)

Hall, Mary [University of Utah

2014-09-19

Enhancing the performance of SciDAC applications on petascale systems has high priority within DOE SC. As we look to the future, achieving expected levels of performance on high-end com-puting (HEC) systems is growing ever more challenging due to enormous scale, increasing archi-tectural complexity, and increasing application complexity. To address these challenges, PERI has implemented a unified, tripartite research plan encompassing: (1) performance modeling and prediction; (2) automatic performance tuning; and (3) performance engineering of high profile applications. The PERI performance modeling and prediction activity is developing and refining performance models, significantly reducing the cost of collecting the data upon which the models are based, and increasing model fidelity, speed and generality. Our primary research activity is automatic tuning (autotuning) of scientific software. This activity is spurred by the strong user preference for automatic tools and is based on previous successful activities such as ATLAS, which has automatically tuned components of the LAPACK linear algebra library, and other re-cent work on autotuning domain-specific libraries. Our third major component is application en-gagement, to which we are devoting approximately 30% of our effort to work directly with Sci-DAC-2 applications. This last activity not only helps DOE scientists meet their near-term per-formance goals, but also helps keep PERI research focused on the real challenges facing DOE computational scientists as they enter the Petascale Era.

NASA Engineering and Safety Center (NESC) Enhanced Melamine (ML) Foam Acoustic Test (NEMFAT)

Science.gov (United States)

McNelis, Anne M.; Hughes, William O.; McNelis, Mark E.

2014-01-01

The NASA Engineering and Safety Center (NESC) funded a proposal to achieve initial basic acoustic characterization of ML (melamine) foam, which could serve as a starting point for a future, more comprehensive acoustic test program for ML foam. A project plan was developed and implemented to obtain acoustic test data for both normal and enhanced ML foam. This project became known as the NESC Enhanced Melamine Foam Acoustic Test (NEMFAT). This document contains the outcome of the NEMFAT project.

Enhancing the performance of brewing yeasts.

Science.gov (United States)

Karabín, Marcel; Jelínek, Lukáš; Kotrba, Pavel; Cejnar, Rudolf; Dostálek, Pavel

2017-12-22

Beer production is one of the oldest known traditional biotechnological processes, but is nowadays facing increasing demands not only for enhanced product quality, but also for improved production economics. Targeted genetic modification of a yeast strain is one way to increase beer quality and to improve the economics of beer production. In this review we will present current knowledge on traditional approaches for improving brewing strains and for rational metabolic engineering. These research efforts will, in the near future, lead to the development of a wider range of industrial strains that should increase the diversity of commercial beers. Copyright © 2018 Elsevier Inc. All rights reserved.

Cardiovascular Effects of Performance-Enhancing Drugs.

Science.gov (United States)

La Gerche, André; Brosnan, Maria J

2017-01-03

Exercise and competitive sports should be associated with a wide range of health benefits with the potential to inspire a positive community health legacy. However, the reputation of sports is being threatened by an ever-expanding armamentarium of agents with real or perceived benefits in performance enhancement. In addition to the injustice of unfair advantage for dishonest athletes, significant potential health risks are associated with performance-enhancing drugs. Performance-enhancing drugs may have an effect on the cardiovascular system by means of directly altering the myocardium, vasculature, and metabolism. However, less frequently considered is the potential for indirect effects caused through enabling athletes to push beyond normal physiological limits with the potential consequence of exercise-induced arrhythmias. This review will summarize the known health effects of PEDs but will also focus on the potentially greater health threat posed by the covert search for performance-enhancing agents that have yet to be recognized by the World Anti-Doping Agency. History has taught us that athletes are subjected to unmonitored trials with experimental drugs that have little or no established efficacy or safety data. One approach to decrease drug abuse in sports would be to accept that there is a delay from when athletes start experimenting with novel agents to the time when authorities become aware of these drugs. This provides a window of opportunity for athletes to exploit with relative immunity. It could be argued that all off-label use of any agent should be deemed illegal. © 2016 American Heart Association, Inc.

Enhanced efficiency of internal combustion engines by employing spinning gas.

Science.gov (United States)

Geyko, V I; Fisch, N J

2014-08-01

The efficiency of the internal combustion engine might be enhanced by employing spinning gas. A gas spinning at near sonic velocities has an effectively higher heat capacity, which allows practical fuel cycles, which are far from the Carnot efficiency, to approach more closely the Carnot efficiency. A remarkable gain in fuel efficiency is shown to be theoretically possible for the Otto and Diesel cycles. The use of a flywheel, in principle, could produce even greater increases in efficiency.

Enhancing discovery in spatial data infrastructures using a search engine

Directory of Open Access Journals (Sweden)

Paolo Corti

2018-05-01

Full Text Available A spatial data infrastructure (SDI is a framework of geospatial data, metadata, users and tools intended to provide an efficient and flexible way to use spatial information. One of the key software components of an SDI is the catalogue service which is needed to discover, query and manage the metadata. Catalogue services in an SDI are typically based on the Open Geospatial Consortium (OGC Catalogue Service for the Web (CSW standard which defines common interfaces for accessing the metadata information. A search engine is a software system capable of supporting fast and reliable search, which may use ‘any means necessary’ to get users to the resources they need quickly and efficiently. These techniques may include full text search, natural language processing, weighted results, fuzzy tolerance results, faceting, hit highlighting, recommendations and many others. In this paper we present an example of a search engine being added to an SDI to improve search against large collections of geospatial datasets. The Centre for Geographic Analysis (CGA at Harvard University re-engineered the search component of its public domain SDI (Harvard WorldMap which is based on the GeoNode platform. A search engine was added to the SDI stack to enhance the CSW catalogue discovery abilities. It is now possible to discover spatial datasets from metadata by using the standard search operations of the catalogue and to take advantage of the new abilities of the search engine, to return relevant and reliable content to SDI users.

Assessing students' performance in software requirements engineering education using scoring rubrics

Science.gov (United States)

Mkpojiogu, Emmanuel O. C.; Hussain, Azham

2017-10-01

The study investigates how helpful the use of scoring rubrics is, in the performance assessment of software requirements engineering students and whether its use can lead to students' performance improvement in the development of software requirements artifacts and models. Scoring rubrics were used by two instructors to assess the cognitive performance of a student in the design and development of software requirements artifacts. The study results indicate that the use of scoring rubrics is very helpful in objectively assessing the performance of software requirements or software engineering students. Furthermore, the results revealed that the use of scoring rubrics can also produce a good achievement assessments direction showing whether a student is either improving or not in a repeated or iterative assessment. In a nutshell, its use leads to the performance improvement of students. The results provided some insights for further investigation and will be beneficial to researchers, requirements engineers, system designers, developers and project managers.

Performance of engineered barrier materials in near surface disposal facilities for radioactive waste. Results of a co-ordinated research project

International Nuclear Information System (INIS)

2001-11-01

The primary objectives of the CRP were to: promote the sharing of experiences of the Member States in their application of engineered barrier materials for near surface disposal facilities; help enhance their use of engineered barriers by improving techniques and methods for selecting, planning and testing performance of various types of barrier materials for near surface disposal facilities. The objective of this publication is to provide and overview of technical issues related to the engineered barrier systems and a summary of the major findings of each individual research project that was carried out within the framework of the CRP. This publication deals with a general overview of engineered barriers in near surface disposal facilities, key technical information obtained within the CRP and overall conclusions and recommendations for future research and development activities. Appendices presenting individual research accomplishments are also provided. Each of the 13 appendices was indexed separately

Hige Compression Ratio Turbo Gasoline Engine Operation Using Alcohol Enhancement

Energy Technology Data Exchange (ETDEWEB)

Heywood, John [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Jo, Young Suk [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Lewis, Raymond [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Bromberg, Leslie [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Heywood, John [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

2016-01-29

The overall objective of this project was to quantify the potential for improving the performance and efficiency of gasoline engine technology by use of alcohols to suppress knock. Knock-free operation is obtained by direct injection of a second “anti-knock” fuel such as ethanol, which suppresses knock when, with gasoline fuel, knock would occur. Suppressing knock enables increased turbocharging, engine downsizing, and use of higher compression ratios throughout the engine’s operating map. This project combined engine testing and simulation to define knock onset conditions, with different mixtures of gasoline and alcohol, and with this information quantify the potential for improving the efficiency of turbocharged gasoline spark-ignition engines, and the on-vehicle fuel consumption reductions that could then be realized. The more focused objectives of this project were therefore to: Determine engine efficiency with aggressive turbocharging and downsizing and high compression ratio (up to a compression ratio of 13.5:1) over the engine’s operating range; Determine the knock limits of a turbocharged and downsized engine as a function of engine speed and load; Determine the amount of the knock-suppressing alcohol fuel consumed, through the use of various alcohol-gasoline and alcohol-water gasoline blends, for different driving cycles, relative to the gasoline consumed; Determine implications of using alcohol-boosted engines, with their higher efficiency operation, in both light-duty and medium-duty vehicle sectors.

PERFORMANCE EVALUATION OF EXTERNAL MIXTURE FORMATION STRATEGY IN HYDROGEN-FUELED ENGINE

Directory of Open Access Journals (Sweden)

Mohammed Kamil

2011-12-01

Full Text Available Mohammed Kamil1, M. M. Rahman2 and Rosli A. Bakar2Hydrogen induction strategy in an internal combustion engine plays a vital role in increasing the power density and prohibiting combustion anomalies. This paper inspects the performance characteristics of cylinder hydrogen-fueled engine with port injection feeding strategy. To that end, a one-dimensional gas dynamic model has been built to represent the flow and heat transfer in the components of the engine. The governing equations are introduced followed by the performance parameters and model description. Air-fuel ratio was varied from a stoichiometric limit to a lean limit. The rotational speed of the engine was also changed from 1000 to 4500 RPM. The injector location was fixed in the mid-point of the intake port. The general behavior of the hydrogen engine was similar to that of a gasoline engine, apart from a reduction in the power density, which was due to a decrease in the volumetric efficiency. This emphasizes the ability of retrofitting traditional engines for hydrogen fuel with minor modifications. The decrease in the volumetric efficiency needs to be rectified.

Engineering Encounters: Teaching Educators about Engineering

Science.gov (United States)

Tank, Kristina M.; Raman, D. Raj; Lamm, Monica H.; Sundararajan, Sriram; Estapa, Anne

2017-01-01

This column presents ideas and techniques to enhance science teaching. This month's issue describes preservice elementary teachers learning engineering principles from engineers. Few elementary teachers have experience with implementing engineering into the classroom. While engineering professional development opportunities for inservice teachers…

Experimental investigations of the hydrogen addition effects on diesel engine performance

Science.gov (United States)

Mirica, I.; Pana, C.; Negurescu, N.; Cernat, A.; Nutu, C.

2016-08-01

In the global content regarding the impact on the environmental of the gases emissions resulted from the fossil fuels combustion, an interest aspect discussed on the 21st Session of the Conference of the Parties from the 2015 Paris Climate Conference and the gradual diminution of the worldwide oil reserves contribute to the necessity of searching of alternative energy from durable and renewable resources. At the use of hydrogen as addition in air to diesel engine, the level of CO, HC and smoke from the exhaust gases will decrease due to the improvement of the combustion process. At low and medium partial loads and low hydrogen energetic ratios used the NOX emission level can decrease comparative to classic diesel engine. The hydrogen use as fuel for diesel engine leads to the improving of the energetic and emissions performance of the engine due to combustion improvement and reduction of carbon content. The paper presents, in a comparative way, results of the experimental researches carried on a truck compression ignition engine fuelled with diesel fuel and with hydrogen diesel fuel and hydrogen as addition in air at different engine operation regimes. The results obtained during experimental investigations show better energetic and pollution performance of the engine fuelled with hydrogen as addition in air comparative to classic engine. The influences of hydrogen addition on engine operation are shown.

Enhancing Engineering Students’ Reading Comprehension of English for Science and Technology With the Support of an Online Cumulative Sentence Analysis System

Directory of Open Access Journals (Sweden)

Yea-Ru Tsai

2014-09-01

Full Text Available For engineering students, reading in English is the core competence to absorb professional knowledge in academic settings and their future career, because many authentic textbooks and information about advanced technology have been published in English. The present study sets out to improve English reading comprehension among tertiary-level engineering students. An online reading strategy instruction based on cumulative sentence analysis (CSA was constructed to enhance the students’ reading comprehension of English technology texts. The comparison between the pre-test and post-test showed that the participants achieved a higher level of reading comprehension performance following the instruction. The findings clearly demonstrated that online CSA strategy instruction is an efficient and feasible approach to helping engineering students cope with their problems of reading English texts. Pedagogical implications are briefly discussed based on the findings of this study.

Judgments about illegal performance-enhancing substances: reasoned, reactive, or both?

Science.gov (United States)

Dodge, Tonya; Stock, Michelle; Litt, Dana

2013-07-01

This study applied aspects of the Theory of Reasoned Action and the Prototype/Willingness model to understand cognitions associated with the use of illegal performance-enhancing substances. There were two study objectives. One was to investigate whether the illegal-is-effective heuristic (i.e. belief that illegal performance-enhancing substances are more effective than legal performance-enhancing substances) affects willingness to use illegal performance-enhancing substances. The second was to examine whether attitudes, norms, and prototypes influence the willingness and intentions to use illegal performance-enhancing substances. The illegal-is-effective heuristic was a significant predictor of willingness but was not a significant predictor of intentions. Implications for future research and prevention efforts are discussed.

Validation of a zero-dimensional model for prediction of NOx and engine performance for electronically controlled marine two-stroke diesel engines

DEFF Research Database (Denmark)

Scappin, Fabio; Stefansson, Sigurður H.; Haglind, Fredrik

2012-01-01

The aim of this paper is to derive a methodology suitable for energy system analysis for predicting the performance and NOx emissions of marine low speed diesel engines. The paper describes a zero-dimensional model, evaluating the engine performance by means of an energy balance and a two zone...... experimental data from two MAN B&W engines; one case being data subject to engine parameter changes corresponding to simulating an electronically controlled engine; the second case providing data covering almost all model input and output parameters. The first case of validation suggests that the model can...

Performance optimization of a Two-Stroke supercharged diesel engine for aircraft propulsion

International Nuclear Information System (INIS)

Carlucci, Antonio Paolo; Ficarella, Antonio; Trullo, Gianluca

2016-01-01

Highlights: • A Two-Stroke diesel engine for aircraft propulsion was modeled with a 0D/1D approach. • The results of the 0D/1D model are compared with those resulting from a 3D model. • The effect of several design and thermodynamic parameters have been analyzed. • Guidelines for the optimization of engine performance are provided. - Abstract: In Two-Stroke engines, the cylinder filling efficiency is antithetical to the cylinder scavenging efficiency; moreover, both of them are influenced by geometric and thermodynamic parameters characterizing the design and operation of both the engine and the related supercharging system. Aim of this work is to provide several guidelines about the definition of design and operation parameters for a Two-Stroke two banks Uniflow diesel engine, supercharged with two sequential turbochargers and an aftercooler per bank, with the goal of either increasing the engine brake power at take-off or decreasing the engine fuel consumption in cruise conditions. The engine has been modeled with a 0D/1D modeling approach. Then, the model capability in describing the effect of several parameters on engine performance has been assessed comparing the results of 3D simulations with those of 0D/1D model. The validated 0D/1D model has been used to simulate the engine behavior varying several design and operation engine parameters (exhaust valves opening and closing angles and maximum valve lift, scavenging ports opening angle, distance between bottom edge of the scavenging ports and bottom dead center, area of the single scavenging port and number of ports, engine volumetric compression ratio, low and high pressure compressor pressure ratios, air/fuel ratio) on a wide range of possible values. The parameters most influencing the engine performance are then recognized and their effect on engine thermodynamic behavior is discussed. Finally, the system configurations leading to best engine power at sea level and lowest fuel consumption in cruise

Surface-enhanced Raman spectroscopy on laser-engineered ruthenium dye-functionalized nanoporous gold

Science.gov (United States)

Schade, Lina; Franzka, Steffen; Biener, Monika; Biener, Jürgen; Hartmann, Nils

2016-06-01

Photothermal processing of nanoporous gold with a microfocused continuous-wave laser at λ = 532 nm provides a facile means in order engineer the pore and ligament size of nanoporous gold. In this report we take advantage of this approach in order to investigate the size-dependence of enhancement effects in surface-enhanced Raman spectroscopy (SERS). Surface structures with laterally varying pore sizes from 25 nm to ≥200 nm are characterized using scanning electron microscopy and then functionalized with N719, a commercial ruthenium complex, which is widely used in dye-sensitized solar cells. Raman spectroscopy reveals the characteristic spectral features of N719. Peak intensities strongly depend on the pore size. Highest intensities are observed on the native support, i.e. on nanoporous gold with pore sizes around 25 nm. These results demonstrate the particular perspectives of laser-fabricated nanoporous gold structures in fundamental SERS studies. In particular, it is emphasized that laser-engineered porous gold substrates represent a very well defined platform in order to study size-dependent effects with high reproducibility and precision and resolve conflicting results in previous studies.

Performance of a hybrid hydrogen–gasoline engine under various operating conditions

International Nuclear Information System (INIS)

Ji, Changwei; Wang, Shuofeng; Zhang, Bo

2012-01-01

Highlights: ► We develop a combustion strategy for the hybrid hydrogen–gasoline engine (HHGE). ► The HHGE produced much lower HC and CO emissions at cold start. ► The H 2 -gasoline blends were effective for improving engine performance at idle and part loads. ► The HHGE could run smoothly at lean conditions. -- Abstract: This paper proposed a new combustion strategy for the spark-ignited (SI) engines. A gasoline engine was converted into a hybrid hydrogen–gasoline engine (HHGE) by adding a hydrogen injection system and a hybrid electronic control unit. Different from the conventional gasoline and hydrogen–enriched gasoline engines, the HHGE is fueled with the pure hydrogen at cold start to produce almost zero emissions, with the hydrogen–gasoline blends at idle and part loads to further improve thermal efficiency and reduce emissions, and with the pure gasoline to ensure the engine power output at high loads. Because the HHGE is fueled with the pure gasoline at high loads and speeds, experiments are only conducted at clod start, idle and part load conditions. Since lean combustion avails the further improvement of the engine performance, the HHGE was fueled with the lean mixtures in all tests. The experimental results showed that the hybrid hydrogen–gasoline engine was started successfully with the pure hydrogen, which produced 94.7% and 99.5% reductions in HC and CO emissions within 100 s from the onset of the cold start, compared with the original gasoline engine. At an excess air ratio of 1.37 and idle conditions, indicated thermal efficiency of the 3% hydrogen–blended gasoline engine was 46.3% higher than that of the original engine. Moreover, the engine cyclic variation was eased, combustion duration was shortened and HC, CO and NOx emissions were effectively reduced for the hybrid hydrogen–gasoline engines.

Gasoline Engine Mechanics. Performance Objectives. Intermediate Course.

Science.gov (United States)

Jones, Marion

Several intermediate performance objectives and corresponding criterion measures are listed for each of six terminal objectives presented in this curriculum guide for an intermediate gasoline engine mechanics course at the secondary level. (For the beginning course guide see CE 010 947.) The materials were developed for a two-semester (2 hour…

Brain performance enhancement for military operators

NARCIS (Netherlands)

Erp, J.B.F.; Reschke, S.; Grootjen, M.; Brouwer, A.-M.

2009-01-01

Performance of military operators depends on both physical and cognitive aspects. Enhancement of operator performance should therefore address both the body and the brain. This paper focuses on the latter. We provide an extended list of areas where neuroscientific knowledge may be important like

Experience with performance based training of nuclear criticality safety engineers

International Nuclear Information System (INIS)

Taylor, R.G.

1993-01-01

Historically, new entrants to the practice of nuclear criticality safety have learned their job primarily by on-the-job training (OJT) often by association with an experienced nuclear criticality safety engineer who probably also learned their job by OJT. Typically, the new entrant learned what he/she needed to know to solve a particular problem and accumulated experience as more problems were solved. It is likely that more formalism will be required in the future. Current US Department of Energy requirements for those positions which have to demonstrate qualification indicate that it should be achieved by using a systematic approach such as performance based training (PBT). Assuming that PBT would be an acceptable mechanism for nuclear criticality safety engineer training in a more formal environment, a site-specific analysis of the nuclear criticality safety engineer job was performed. Based on this analysis, classes are being developed and delivered to a target audience of newer nuclear criticality safety engineers. Because current interest is in developing training for selected aspects of the nuclear criticality safety engineer job, the analysis i's incompletely developed in some areas. Details of this analysis are provided in this report

Design of a high-performance rotary stratified-charge research aircraft engine

Science.gov (United States)

Jones, C.; Mount, R. E.

1984-01-01

The power section for an advanced rotary stratified-charge general aviation engine has been designed under contract to NASA. The single-rotor research engine of 40 cubic-inches displacement (RCI-40), now being procured for test initiation this summer, is targeted for 320 T.O. horse-power in a two-rotor production engine. The research engine is designed for operating on jet-fuel, gasoline or diesel fuel and will be used to explore applicable advanced technologies and to optimize high output performance variables. Design of major components of the engine is described in this paper.

Infrared suppressor effect on T63 turboshaft engine performance

Science.gov (United States)

Bailey, E. E.; Civinskas, K. C.; Walker, C. L.

1978-01-01

Tests were conducted to determine if there are performance penalties associated with the installation of infrared (IR) suppressors on the T63-A-700 turboshaft engine. The testing was done in a sea-level, static test cell. The same engine (A-E402808 B) was run with the standard OH-58 aircraft exhaust stacks and with the ejector-type IR suppressors in order to make a valid comparison. Repeatability of the test results for the two configurations was verified by rerunning the conditions over a period of days. Test results showed no measurable difference in performance between the standard exhaust stacks and the IR suppressors.

Human performance models for computer-aided engineering

Science.gov (United States)

Elkind, Jerome I. (Editor); Card, Stuart K. (Editor); Hochberg, Julian (Editor); Huey, Beverly Messick (Editor)

1989-01-01

This report discusses a topic important to the field of computational human factors: models of human performance and their use in computer-based engineering facilities for the design of complex systems. It focuses on a particular human factors design problem -- the design of cockpit systems for advanced helicopters -- and on a particular aspect of human performance -- vision and related cognitive functions. By focusing in this way, the authors were able to address the selected topics in some depth and develop findings and recommendations that they believe have application to many other aspects of human performance and to other design domains.

NUTRITIONAL ENHANCEMENT OF ALFALFA THROUGH GENETIC ENGINEERING

Directory of Open Access Journals (Sweden)

J. Faragó

2008-09-01

Full Text Available Alfalfa (Medicago sativa L. is a pasture legume crop of primary importance to animal production throughout the world. The nutritional quality of alfalfa, as of other leguminous forage crops, is mainly determined by their content in selected essential amino acids (EAAs, such as methionine (Met and cysteine (Cys. In alfalfa, however, these S-containing amino acids constitute only about 1% or less of crude proteins (Frame et al., 1998. This is significantly less than the 3.5% Met+Cys content in the recommended FAO reference protein (FAO, 1973. Recent advances in genetic engineering allow to use the transgenic approach to increase the content of specific essential amino acids in target plant species. A number of different molecular approaches have been developed to address this issue, such as over-expression of a heterologous or homologous Met-rich protein, expression of a synthetic protein, modification of protein sequence, and metabolic engineering of the free amino acid pool and protein sink. To study the possibility of transgenic enhancement of nutritional quality of alfalfa, we used the approach of expression of a heterologous protein rich in Met+Cys in cells of alfalfa. The T-DNA introduced into the genome of alfalfa, using Agrobacterium tumefaciens-mediated genetic transformation, contained the selectable merker gene nptII for kanamycin (Kn resistance, and a cDNA of Ov gene from Japanese quail (Coturnix coturnix coding for a high Met+Cys containing ovalbumine (Mucha et al., 1991, both under constitutive promoters. After cocultivation of petiole segment- and leaf blade-explants of two highly embryogenic alfalfa genotypes Rg9/I-14-22 and Rg11/I-10-68 (Faragó et al., 1997 with cells of A. tumefaciens strain AGL1 carrying the nptII and Ov genes, and selection of transgenic cells on Kn containing selective media, more than one hundred putatively transgenic regenerants were obtained through somatic embryogenesis. Biological (Kn rooting assay

Engine performance testing using variable RON95 fuel brands available in Malaysia

Directory of Open Access Journals (Sweden)

Mohd Riduan Aizuddin Fahmi

2017-01-01

Full Text Available There are various gasoline fuel producers available in Malaysia. The effects of fuel variations from different manufacturers on vehicle performance have always been a debate among users and currently the facts still remains inconclusive. Hence, this study focuses on analyzing various RON95 fuel brands available in the Malaysian market and finding the differences towards engine performance. In terms of engine output, the important data of power (hp and torque (Nm will be gathered by using an engine dynamometer. Another data that would also be taken into account is the knocking where the relative knock index can be measured in percentage using the knock sensor accelerometer. Results have shown that the performance of different fuel brands tested are indeed different albeit by only a small margin even though all fuels are categorized with the same octane rating. The power and torque results also imply that both are influenced by the amount of vibration generated due to engine knocking. Based from the overall outcome, consumers would not need to only focus on a certain type of gasoline brand as all differentiates the engine performance marginally.

Software Engineering Improvement Activities/Plan

Science.gov (United States)

2003-01-01

bd Systems personnel accomplished the technical responsibilities for this reporting period, as planned. A close working relationship was maintained with personnel of the MSFC Avionics Department Software Group (ED14). Work accomplishments included development, evaluation, and enhancement of a software cost model, performing literature search and evaluation of software tools available for code analysis and requirements analysis, and participating in other relevant software engineering activities. Monthly reports were submitted. This support was provided to the Flight Software Group/ED 1 4 in accomplishing the software engineering improvement engineering activities of the Marshall Space Flight Center (MSFC) Software Engineering Improvement Plan.

Effect of Engine Modifications on Performance and Emission Characteristics of Diesel Engines with Alternative Fuels

OpenAIRE

Venkateswarlu, K.; Murthy, B.S.R

2010-01-01

Performance and emission characteristics unmodified diesel engines operating on different alternative fuels with smaller blend proportions are comparable with pure diesel operation. But with increased blend proportions due to the associated problems of vegetable oils like high viscosity and low volatility pollution levels increase which however is accompanied by operating and durability problems with the long term usage of engine. This paper discusses the necessary modifications required to o...

Engine Of Innovation: Building the High Performance Catalog

Directory of Open Access Journals (Sweden)

Will Owen

2015-06-01

Full Text Available Numerous studies have indicated the sophisticated web-based search engines have eclipsed the primary importance of the library catalog as the premier tool for researchers in Higher education.  We submit that the catalog remains central to the research process.  Through a series of strategic enhancements, the University of North Carolina at Chapel Hill, in partnership with the other members of the Triangle Research Libraries Network, has made the catalog a carrier of services in addition to bibliographic data, facilitating not simply discovery but also delivery of the information researchers seek.

Boosting the ambipolar performance of solution-processable polymer semiconductors via hybrid side-chain engineering.

Science.gov (United States)

Lee, Junghoon; Han, A-Reum; Yu, Hojeong; Shin, Tae Joo; Yang, Changduk; Oh, Joon Hak

2013-06-26

Ambipolar polymer semiconductors are highly suited for use in flexible, printable, and large-area electronics as they exhibit both n-type (electron-transporting) and p-type (hole-transporting) operations within a single layer. This allows for cost-effective fabrication of complementary circuits with high noise immunity and operational stability. Currently, the performance of ambipolar polymer semiconductors lags behind that of their unipolar counterparts. Here, we report on the side-chain engineering of conjugated, alternating electron donor-acceptor (D-A) polymers using diketopyrrolopyrrole-selenophene copolymers with hybrid siloxane-solubilizing groups (PTDPPSe-Si) to enhance ambipolar performance. The alkyl spacer length of the hybrid side chains was systematically tuned to boost ambipolar performance. The optimized three-dimensional (3-D) charge transport of PTDPPSe-Si with pentyl spacers yielded unprecedentedly high hole and electron mobilities of 8.84 and 4.34 cm(2) V(-1) s(-1), respectively. These results provide guidelines for the molecular design of semiconducting polymers with hybrid side chains.

High Performance Computing in Science and Engineering '15 : Transactions of the High Performance Computing Center

CERN Document Server

Kröner, Dietmar; Resch, Michael

2016-01-01

This book presents the state-of-the-art in supercomputer simulation. It includes the latest findings from leading researchers using systems from the High Performance Computing Center Stuttgart (HLRS) in 2015. The reports cover all fields of computational science and engineering ranging from CFD to computational physics and from chemistry to computer science with a special emphasis on industrially relevant applications. Presenting findings of one of Europe’s leading systems, this volume covers a wide variety of applications that deliver a high level of sustained performance. The book covers the main methods in high-performance computing. Its outstanding results in achieving the best performance for production codes are of particular interest for both scientists and engineers. The book comes with a wealth of color illustrations and tables of results.

High Performance Computing in Science and Engineering '17 : Transactions of the High Performance Computing Center

CERN Document Server

Kröner, Dietmar; Resch, Michael; HLRS 2017

2018-01-01

This book presents the state-of-the-art in supercomputer simulation. It includes the latest findings from leading researchers using systems from the High Performance Computing Center Stuttgart (HLRS) in 2017. The reports cover all fields of computational science and engineering ranging from CFD to computational physics and from chemistry to computer science with a special emphasis on industrially relevant applications. Presenting findings of one of Europe’s leading systems, this volume covers a wide variety of applications that deliver a high level of sustained performance.The book covers the main methods in high-performance computing. Its outstanding results in achieving the best performance for production codes are of particular interest for both scientists and engineers. The book comes with a wealth of color illustrations and tables of results.

Fine-tuning blend morphology via alkylthio side chain engineering towards high performance non-fullerene polymer solar cells

Science.gov (United States)

Li, Ling; Feng, Liuliu; Yuan, Jun; Peng, Hongjian; Zou, Yingping; Li, Yongfang

2018-03-01

Two medium bandgap polymers (ffQx-TS1, ffQx-TS2) were designed and synthesized to investigate the influence of different alkylthio side chain on the morphology and photovoltaic performance of non-fullerene polymer solar cells (PSCs). Both polymers exhibit similar molecular weights and comparable the highest occupied molecular orbital (HOMO) energy level. However, the polymer with straight alkylthio chain delivers a root-mean-square (RMS) of 0.86 nm, which is slightly lower than that with branched chain (1.40 nm). The lower RMS benefits the ohmic contact between the active lay and interface layer, thus enhanced short circuit current (Jsc) (from 13.54 mA cm-1 to 15.25 mA cm-1) could be obtained. Due to the enhancement of Jsc, better power conversion efficiency (PCE) of 7.69% for ffQx-TS2 could be realized. These results indicated that alkylthio side chain engineering is a promising method to improve photovoltaic performance.

Performance of compression ignition engine with indigenous castor oil bio diesel in Pakistan

International Nuclear Information System (INIS)

Chakrabarti, M.H.

2009-01-01

Castor oil available indigenously in Pakistan was converted successfully to bio diesel and blended to 10% quantity (by volume) with high speed mineral diesel (HSD) fuel. This fuel was tested in a compression-ignition engine in order to assess its environmental emissions as well as engine performance parameters. The blended fuel was found to give lower environmental emissions in most accounts except for higher CO/sub 2/ and higher NOx. In addition, three engine performance parameters were assessed; which were engine brake power, engine torque and exhaust temperature. In the first two cases, blended bio diesel fuel gave lower figures than pure mineral diesel due to lower calorific value. However, its higher flash point resulted in higher engine exhaust temperatures than pure mineral diesel. Overall, in terms of engine performance, castor oil bio diesel (from non edible oil of castor bean -growing on marginal lands of Pakistan) fared better in comparison to canola oil bio diesel (from expensive edible oil) and can be recommended for further tests at higher blend ratios. (author)

Performance and efficiency evaluation and heat release study of a direct-injection stratified-charge rotary engine

Science.gov (United States)

Nguyen, H. L.; Addy, H. E.; Bond, T. H.; Lee, C. M.; Chun, K. S.

1987-01-01

A computer simulation which models engine performance of the Direct Injection Stratified Charge (DISC) rotary engines was used to study the effect of variations in engine design and operating parameters on engine performance and efficiency of an Outboard Marine Corporation (OMC) experimental rotary combustion engine. Engine pressure data were used in a heat release analysis to study the effects of heat transfer, leakage, and crevice flows. Predicted engine data were compared with experimental test data over a range of engine speeds and loads. An examination of methods to improve the performance of the rotary engine using advanced heat engine concepts such as faster combustion, reduced leakage, and turbocharging is also presented.

Predicting performance in a first engineering calculus course: implications for interventions

Science.gov (United States)

Hieb, Jeffrey L.; Lyle, Keith B.; Ralston, Patricia A. S.; Chariker, Julia

2015-01-01

At the University of Louisville, a large, urban institution in the south-east United States, undergraduate engineering students take their mathematics courses from the school of engineering. In the fall of their freshman year, engineering students take Engineering Analysis I, a calculus-based engineering analysis course. After the first two weeks of the semester, many students end up leaving Engineering Analysis I and moving to a mathematics intervention course. In an effort to retain more students in Engineering Analysis I, the department collaborated with university academic support services to create a summer intervention programme. Students were targeted for the summer programme based on their score on an algebra readiness exam (ARE). In a previous study, the ARE scores were found to be a significant predictor of retention and performance in Engineering Analysis I. This study continues that work, analysing data from students who entered the engineering school in the fall of 2012. The predictive validity of the ARE was verified, and a hierarchical linear regression model was created using math American College Testing (ACT) scores, ARE scores, summer intervention participation, and several metacognitive and motivational factors as measured by subscales of the Motivated Strategies for Learning Questionnaire. In the regression model, ARE score explained an additional 5.1% of the variation in exam performance in Engineering Analysis I beyond math ACT score. Students took the ARE before and after the summer interventions and scores were significantly higher following the intervention. However, intervention participants nonetheless had lower exam scores in Engineering Analysis I. The following factors related to motivation and learning strategies were found to significantly predict exam scores in Engineering Analysis I: time and study environment management, internal goal orientation, and test anxiety. The adjusted R2 for the full model was 0.42, meaning that the

Sensorimotor Rhythm Neurofeedback Enhances Golf Putting Performance.

Science.gov (United States)

Cheng, Ming-Yang; Huang, Chung-Ju; Chang, Yu-Kai; Koester, Dirk; Schack, Thomas; Hung, Tsung-Min

2015-12-01

Sensorimotor rhythm (SMR) activity has been related to automaticity during skilled action execution. However, few studies have bridged the causal link between SMR activity and sports performance. This study investigated the effect of SMR neurofeedback training (SMR NFT) on golf putting performance. We hypothesized that preelite golfers would exhibit enhanced putting performance after SMR NFT. Sixteen preelite golfers were recruited and randomly assigned into either an SMR or a control group. Participants were asked to perform putting while electroencephalogram (EEG) was recorded, both before and after intervention. Our results showed that the SMR group performed more accurately when putting and exhibited greater SMR power than the control group after 8 intervention sessions. This study concludes that SMR NFT is effective for increasing SMR during action preparation and for enhancing golf putting performance. Moreover, greater SMR activity might be an EEG signature of improved attention processing, which induces superior putting performance.

Enhanced optical coupling and Raman scattering via microscopic interface engineering

Science.gov (United States)

Thompson, Jonathan V.; Hokr, Brett H.; Kim, Wihan; Ballmann, Charles W.; Applegate, Brian E.; Jo, Javier A.; Yamilov, Alexey; Cao, Hui; Scully, Marlan O.; Yakovlev, Vladislav V.

2017-11-01

Spontaneous Raman scattering is an extremely powerful tool for the remote detection and identification of various chemical materials. However, when those materials are contained within strongly scattering or turbid media, as is the case in many biological and security related systems, the sensitivity and range of Raman signal generation and detection is severely limited. Here, we demonstrate that through microscopic engineering of the optical interface, the optical coupling of light into a turbid material can be substantially enhanced. This improved coupling facilitates the enhancement of the Raman scattering signal generated by molecules within the medium. In particular, we detect at least two-orders of magnitude more spontaneous Raman scattering from a sample when the pump laser light is focused into a microscopic hole in the surface of the sample. Because this approach enhances both the interaction time and interaction region of the laser light within the material, its use will greatly improve the range and sensitivity of many spectroscopic techniques, including Raman scattering and fluorescence emission detection, inside highly scattering environments.

Control room human engineering influences on operator performance

International Nuclear Information System (INIS)

Finlayson, F.C.

1977-01-01

Three general groups of factors influence operator performance in fulfilling their responsibilities in the control room: (1) control room and control system design, informational data displays (operator inputs) as well as control board design (for operator output); (2) operator characteristics, including those skills, mental, physical, and emotional qualities which are functions of operator selection, training, and motivation; (3) job performance guides, the prescribed operating procedures for normal and emergency operations. This paper presents some of the major results of an evaluation of the effect of human engineering on operator performance in the control room. Primary attention is given to discussion of control room and control system design influence on the operator. Brief observations on the influences of operator characteristics and job performance guides (operating procedures) on performance in the control room are also given. Under the objectives of the study, special emphasis was placed on the evaluation of the control room-operator relationships for severe emergency conditions in the power plant. Consequently, this presentation is restricted largely to material related to emergency conditions in the control room, though it is recognized that human engineering of control systems is of equal (or greater) importance for many other aspects of plant operation

Systems Engineering Initiative: Undergraduate Education Enhancement in a Regional Education Network

International Nuclear Information System (INIS)

Kurwitz, R. C.; Peddicord, K.; Poston, J.; Yang, X.; Bostanci, H.

2016-01-01

Full text: The Systems Engineering Initiative (SEI) is an experience based education enhancement programme that forms teams of undergraduate students with faculty and industry mentors to solve problems of interest to industry. This model of innovation creates a new learning paradigm that is outside the traditional classroom based model and fits more of the Master-apprentice model as applied to engineering teams. The SEI programme is currently administered by the Nuclear Power Institute (NPI), a regional nuclear education network, and is being carried out at three partner universities. Previous nuclear related projects have benefited industry and are of high technical quality with publications in peer-reviewed journals and awards for presentations in various forums. Students within the programme have benefited through development of soft skills outside the traditional curriculum, understanding of how their knowledge fits into a nuclear organization, and exposure to career opportunities. Industry and other NPI stakeholders benefit from the development of capable engineers and technicians, positive outreach to the community, and most importantly, knowledge transfer to the next generation of nuclear professionals. (author

Study of two-stage turbine characteristic and its influence on turbo-compound engine performance

International Nuclear Information System (INIS)

Zhao, Rongchao; Zhuge, Weilin; Zhang, Yangjun; Yang, Mingyang; Martinez-Botas, Ricardo; Yin, Yong

2015-01-01

Highlights: • An analytical model was built to study the interactions between two turbines in series. • The impacts of HP VGT and LP VGT on turbo-compound engine performance were investigated. • The fuel reductions obtained by HP VGT at 1900 rpm and 1000 rpm are 3.08% and 7.83% respectively. • The optimum value of AR ranged from 2.0 to 2.5 as the turbo-compound engine speed decreases. - Abstract: Turbo-compounding is an effective way to recover waste heat from engine exhaust and reduce fuel consumption for internal combustion engine (ICE). The characteristics of two-stage turbine, including turbocharger turbine and power turbine, have significant effects on the overall performance of turbo-compound engine. This paper investigates the interaction between two turbines in a turbo-compound engine and its impact on the engine performance. Firstly an analytical model is built to investigate the effects of turbine equivalent flow area on the two-stage turbine characteristics, including swallowing capacity and load split. Next both simulation and experimental method are carried out to study the effects of high pressure variable geometry turbine (HP VGT), low pressure variable geometry turbine (LP VGT) and combined VGT on the engine overall performance. The results show that the engine performance is more sensitive to HP VGT compared with LP VGT at all the operation conditions, which is caused by the larger influences of HP VGT on the total expansion ratio and engine air–fuel ratio. Using the HP VGT method, the fuel reductions of the turbo-compound engine at 1900 rpm and 1000 rpm are 3.08% and 7.83% respectively, in comparison with the baseline engine. The corresponding optimum values of AR are 2.0 and 2.5

Training to Enhance Design Team Performance: A Cure for Tunnel Vision

Science.gov (United States)

Parker, James W.; Parker, Nelson C. (Technical Monitor)

2001-01-01

Design Team performance is a function of the quality and degree of academic training and the cumulative, learned experience of the individual members of the team. Teamwork, leadership, and communications certainly are factors that affect the measure of the performance of the team, but they are not addressed here. This paper focuses on accelerating the learned experience of team members and describes an organizational approach that can significantly increase the effective experience level for any engineering design team. The performance measure of the whole team can be increased by increasing the engineering disciplines' cross awareness of each other and by familiarizing them with their affect at the system level. Discipline engineers know their own discipline well, but typically are not intimately familiar with their technical interaction with and dependencies on all the other disciplines of engineering. These dependencies are design integration functions and are worked out well by the discipline engineers as long as they are involved in the design of types of systems that they have experience with.

Performance engineering in the community atmosphere model

International Nuclear Information System (INIS)

Worley, P; Mirin, A; Drake, J; Sawyer, W

2006-01-01

The Community Atmosphere Model (CAM) is the atmospheric component of the Community Climate System Model (CCSM) and is the primary consumer of computer resources in typical CCSM simulations. Performance engineering has been an important aspect of CAM development throughout its existence. This paper briefly summarizes these efforts and their impacts over the past five years

Sensor Selection for Aircraft Engine Performance Estimation and Gas Path Fault Diagnostics

Science.gov (United States)

Simon, Donald L.; Rinehart, Aidan W.

2016-01-01

This paper presents analytical techniques for aiding system designers in making aircraft engine health management sensor selection decisions. The presented techniques, which are based on linear estimation and probability theory, are tailored for gas turbine engine performance estimation and gas path fault diagnostics applications. They enable quantification of the performance estimation and diagnostic accuracy offered by different candidate sensor suites. For performance estimation, sensor selection metrics are presented for two types of estimators including a Kalman filter and a maximum a posteriori estimator. For each type of performance estimator, sensor selection is based on minimizing the theoretical sum of squared estimation errors in health parameters representing performance deterioration in the major rotating modules of the engine. For gas path fault diagnostics, the sensor selection metric is set up to maximize correct classification rate for a diagnostic strategy that performs fault classification by identifying the fault type that most closely matches the observed measurement signature in a weighted least squares sense. Results from the application of the sensor selection metrics to a linear engine model are presented and discussed. Given a baseline sensor suite and a candidate list of optional sensors, an exhaustive search is performed to determine the optimal sensor suites for performance estimation and fault diagnostics. For any given sensor suite, Monte Carlo simulation results are found to exhibit good agreement with theoretical predictions of estimation and diagnostic accuracies.

Some research advances in computer graphics that will enhance applications to engineering design

Science.gov (United States)

Allan, J. J., III

1975-01-01

Research in man/machine interactions and graphics hardware/software that will enhance applications to engineering design was described. Research aspects of executive systems, command languages, and networking used in the computer applications laboratory are mentioned. Finally, a few areas where little or no research is being done were identified.

Four-Stroke, Internal Combustion Engine Performance Modeling

Science.gov (United States)

Wagner, Richard C.

In this thesis, two models of four-stroke, internal combustion engines are created and compared. The first model predicts the intake and exhaust processes using isentropic flow equations augmented by discharge coefficients. The second model predicts the intake and exhaust processes using a compressible, time-accurate, Quasi-One-Dimensional (Q1D) approach. Both models employ the same heat release and reduced-order modeling of the cylinder charge. Both include friction and cylinder loss models so that the predicted performance values can be compared to measurements. The results indicate that the isentropic-based model neglects important fluid mechanics and returns inaccurate results. The Q1D flow model, combined with the reduced-order model of the cylinder charge, is able to capture the dominant intake and exhaust fluid mechanics and produces results that compare well with measurement. Fluid friction, convective heat transfer, piston ring and skirt friction and temperature-varying specific heats in the working fluids are all shown to be significant factors in engine performance predictions. Charge blowby is shown to play a lesser role.

Performance of heat engines with non-zero heat capacity

International Nuclear Information System (INIS)

Odes, Ron; Kribus, Abraham

2013-01-01

Highlights: ► Finite heat capacity is a second irreversibility mechanism in addition to thermal resistance. ► Heat capacity introduces thermal transients and reverse heat flow. ► Engine maximum power and efficiency are lower for finite heat capacity. ► Implementing the optimal engine cycle requires active control. - Abstract: The performance of a heat engine is analyzed subject to two types of irreversibility: a non-zero heat capacity, together with the more common finite heat transfer rate between the engine and the external heat reservoirs. The heat capacity represents an engine body that undergoes significant temperature variations during the engine cycle. An option to cut off the heat exchange between the engine and the external surrounding for part of the engine cycle is also explored. A variational approach was taken to find the engine’s internal temperature profile (which defines the internal thermodynamic cycle) that would produce maximum power. The maximum power is shown to be lower than the case of zero heat capacity, due to a loss of heat that is stored in the engine body and then lost, bypassing the thermodynamic cycle. The maximum efficiency and the efficiency at maximum power are also lower than the zero heat capacity case. Similar to the Curzon–Ahlborn analysis, power can be traded for increased efficiency, but for high heat capacity, the range of efficiency that is available for such a trade is diminished. Isolating the engine during part of the cycle reduces maximum power, but the efficiency at maximum power and the maximum efficiency are improved, due to better exploitation of heat stored in the engine body. This might be useful for real engines that are limited by the internal energy change during a single engine cycle or by the operating frequency, leading to a broader power–efficiency curve.

Quantum Engineering of States in Heterostructure-based Detectors for Enhance Performance

Science.gov (United States)

2017-05-26

THIS PAGE U 19b. TELEPHONE NUMBER (Include area code) (847) 962-4955 Standard Form 298 (Rev. 8/98) Prescribed by ANSI Std. Z39.18 Adobe ...Since Figure 3 illustrates the association of parameters of the In1-yGayAs single-double well design and with...and = . × −. Figure 4 illustrates the demands for signal-to-noise enhanced photodetector. In In1

Thermal conductivity engineering in width-modulated silicon nanowires and thermoelectric efficiency enhancement

Science.gov (United States)

Zianni, Xanthippi

2018-03-01

Width-modulated nanowires have been proposed as efficient thermoelectric materials. Here, the electron and phonon transport properties and the thermoelectric efficiency are discussed for dimensions above the quantum confinement regime. The thermal conductivity decreases dramatically in the presence of thin constrictions due to their ballistic thermal resistance. It shows a scaling behavior upon the width-modulation rate that allows for thermal conductivity engineering. The electron conductivity also decreases due to enhanced boundary scattering by the constrictions. The effect of boundary scattering is weaker for electrons than for phonons and the overall thermoelectric efficiency is enhanced. A ZT enhancement by a factor of 20-30 is predicted for width-modulated nanowires compared to bulk silicon. Our findings indicate that width-modulated nanostructures are promising for developing silicon nanostructures with high thermoelectric efficiency.

Effect of poultry fat oil biodiesel on tractor engine performance

Directory of Open Access Journals (Sweden)

M Bavafa

2016-04-01

Full Text Available Introduction: Depletion of fossil fuels and environmental degradation are two major problems faced by the world. Today fossil fuels take up to 80% of the primary energy consumed in the world, of which 58% is consumed by the transport sector alone (Mard et al., 2012. The combustion products cause global warming, which is caused of emissions like carbon monoxide (CO, sulfur dioxide (SO2 and nitrogen oxides (NOX. Thus it is essential that low emission alternative fuels to be developed for useing in diesel engines. Many researchers have concluded that biodiesel holds promise as an alternative fuel for diesel engines. Biodiesel is oxygenated, biodegradable, non-toxic, and environmentally friendly (Qi et al., 2010. Materials and Methods: In this study transesterification method was used to produce biodiesel, because of its simplicity in biodiesel production process and holding the highest conversion efficiency. Transesterification of poultry fat oil and the properties of the fuels: Fatty acid methyl ester of poultry fat oil was prepared by transesterification of oil with methanol in the presence of KOH as catalyst. The fuel properties of poultry fat oil methyl ester and diesel fuel were determined. These properties are presented in Table 1. Tests of engine performance and emissions: After securing the qualitative characteristics of produced biodiesel, different biodiesel fuels of 5%, 10%, 15%, and 20% blended with diesel fuel were prepared. A schematic diagram of the engine setup is shown in Fig.1. The MF-399 tractor engine was used in the tests. The basic specifications of the engine are shown in Table 3. The engine was loaded with an electromagnetic dynamometer. The Σ5 model dynamometer manufactured by NJ-FROMENT was used to measure the power and the torque of the tractor engine. The speed range and capacity of this device are shown in Table 2. A FTO Flow Meter, manufactured by American FLOWTECH Company, was used to measure the fuel consumption

Thermal performance of a Stirling engine powered by a solar simulator

International Nuclear Information System (INIS)

Aksoy, Fatih; Karabulut, Halit; Çınar, Can; Solmaz, Hamit; Özgören, Yasar Önder; Uyumaz, Ahmet

2015-01-01

In this study, the performance of a beta type Stirling engine which works at relatively lower temperatures was investigated using 400 W and 1000 W halogen lamps as a heat source and helium as the working fluid. The working fluid was charged into the engine block and the pressure of the working fluid was ranged from 1 to 5 bars with 1 bar increments. The halogen lamps were placed into a cavity adjacent to the hot end of the displacer cylinder, which is made of aluminum alloy. In the experiments conducted with 400 W halogen lamp, the temperature of the cavity was 623 ± 10 K. The power, torque and thermal efficiency of the engine were determined to be 37.08 W, 1.68 Nm and 9.27%, at 5 bar charge pressure. For the 1000 W halogen lamp, the temperature of the cavity was determined to be 873 ± 10 K. The power, torque and thermal efficiency of the engine were determined to be 127.17 W, 3.4 Nm and 12.85%, at the same charge pressure. The experimental thermal efficiencies of the engine were also compared with thermodynamic nodal analysis. - Highlights: • The performance of a beta type Stirling engine was investigated. • 400 and 1000 W halogen lamps were used as a solar simulator in the experiments. • Cavity temperature was measured 623 and 873 K for 400 and 1000 W lamps. • 1000 W halogen lamp provided better engine performance and thermal efficiency. • Experimental results of efficiency were compared with nodal analysis results

Over compression influence to the performances of the spark ignition engines

Science.gov (United States)

Rakosi, E.; Talif, S. G.; Manolache, G.

2016-08-01

This paper presents the theoretical and experimental results of some procedures used in improving the performances of the automobile spark ignition engines. The study uses direct injection and high over-compression applied to a standard engine. To this purpose, the paper contains both the constructive solutions and the results obtained from the test bed concerning the engine power indices, fuel consumption and exhaust emissions.

Peripheral visual performance enhancement by neurofeedback training.

Science.gov (United States)

Nan, Wenya; Wan, Feng; Lou, Chin Ian; Vai, Mang I; Rosa, Agostinho

2013-12-01

Peripheral visual performance is an important ability for everyone, and a positive inter-individual correlation is found between the peripheral visual performance and the alpha amplitude during the performance test. This study investigated the effect of alpha neurofeedback training on the peripheral visual performance. A neurofeedback group of 13 subjects finished 20 sessions of alpha enhancement feedback within 20 days. The peripheral visual performance was assessed by a new dynamic peripheral visual test on the first and last training day. The results revealed that the neurofeedback group showed significant enhancement of the peripheral visual performance as well as the relative alpha amplitude during the peripheral visual test. It was not the case in the non-neurofeedback control group, which performed the tests within the same time frame as the neurofeedback group but without any training sessions. These findings suggest that alpha neurofeedback training was effective in improving peripheral visual performance. To the best of our knowledge, this is the first study to show evidence for performance improvement in peripheral vision via alpha neurofeedback training.

Development of Key Performance Indicators for the Engineering Technology Education Programs in Taiwan

Science.gov (United States)

Lee, Lung-Sheng; Lai, Chun-Chin

2004-01-01

In comparison with engineering, engineering technology is more practical and purposeful. The engineering technology education programs in Taiwan have been mainly offered in 56 universities/colleges of technology (UTs/CTs) and are anticipated to continuously improve their performance to prepare quality engineering technologists. However, it is…

Experimental Study on Revetec Engine Cam Performance

International Nuclear Information System (INIS)

Gasim, Maisara Mohyeldin; Chui, Lee Giok; Anwar, Khirul Azhar bin

2012-01-01

In Revetec engine (three-lobed) cam replaces the crankshaft to convert the reciprocating motion of the engine piston, to a rotating motion in the drive line. Since the cam controls the piston movement, the cam profile has a great effect on engine performance. In this paper an experimental study was done to a (three- lobed) cam with Cycloidal motion profile but with different ratios between the base circle radius of the cam and the radius of the roller follower. DEWESoft was used to find the displacement and the vibration of the piston, and compare the actual results from the test with the theoretical results from the cam profile equation. The results showed that there is a periods of miss contact between the follower and the cam when the ratio between the base circle radius of the cam and the radius of the roller follower is less than a certain value, and also increasing of vibration. The suggested ratio between the cam and follower radius is to be more than 2:1.

Internal Flow Simulation of Enhanced Performance Solid Rocket Booster for the Space Transportation System

Science.gov (United States)

Ahmad, Rashid A.; McCool, Alex (Technical Monitor)

2001-01-01

An enhanced performance solid rocket booster concept for the space shuttle system has been proposed. The concept booster will have strong commonality with the existing, proven, reliable four-segment Space Shuttle Reusable Solid Rocket Motors (RSRM) with individual component design (nozzle, insulator, etc.) optimized for a five-segment configuration. Increased performance is desirable to further enhance safety/reliability and/or increase payload capability. Performance increase will be achieved by adding a fifth propellant segment to the current four-segment booster and opening the throat to accommodate the increased mass flow while maintaining current pressure levels. One development concept under consideration is the static test of a "standard" RSRM with a fifth propellant segment inserted and appropriate minimum motor modifications. Feasibility studies are being conducted to assess the potential for any significant departure in component performance/loading from the well-characterized RSRM. An area of concern is the aft motor (submerged nozzle inlet, aft dome, etc.) where the altered internal flow resulting from the performance enhancing features (25% increase in mass flow rate, higher Mach numbers, modified subsonic nozzle contour) may result in increased component erosion and char. To assess this issue and to define the minimum design changes required to successfully static test a fifth segment RSRM engineering test motor, internal flow studies have been initiated. Internal aero-thermal environments were quantified in terms of conventional convective heating and discrete phase alumina particle impact/concentration and accretion calculations via Computational Fluid Dynamics (CFD) simulation. Two sets of comparative CFD simulations of the RSRM and the five-segment (IBM) concept motor were conducted with CFD commercial code FLUENT. The first simulation involved a two-dimensional axi-symmetric model of the full motor, initial grain RSRM. The second set of analyses

Effect of turbocharging system on the performance of a natural gas engine

International Nuclear Information System (INIS)

Kesgin, Ugur

2005-01-01

The effect of the turbocharging system on the performance of the gas engine family, which is used in combined power plants, is investigated. These investigations show a clear improvement potential for the future of the engine series optimised here. To do this, a computational model in which zero dimensional phenomena within the cylinder and one dimensional phenomena in the engine inlet and exhaust system are used is verified. Using this engine model, the effects of the parameters of the exhaust and turbocharging system on the engine performance are obtained. In particular, the following parameters are chosen: diameter of the exhaust manifold, diameter of the pipe at the turbine exit, efficiency of the turbocharger, location of the turbocharger, back pressure at the turbine exit and pressure losses (resistances) before the compressor. This paper presents the results of these investigations

Air and fuel supercharge in the performance of a diesel cycle engine

Directory of Open Access Journals (Sweden)

Marcelo Silveira de Farias

Full Text Available ABSTRACT: This paper aimed to evaluate the performance of a Diesel cycle engine, changing the configurations for the air and fuel supply system. Variables analyzed were torque, power, specific fuel consumption and thermal efficiency in four different engine configurations (aspirated, aspirated + service, turbocharged + service and turbocharged. For that, there were dynamometer experiments by power take-off of an agricultural tractor. The experimental outline used was entirely randomized, in a bifatorial design with three repetitions. Results indicated that the engine supercharge, compared to its original configuration, provided a significant increase of torque and power. Only the addition of turbo does not caused a significant effect in the engine performance. Application of turbocharger provides an improvement in the burning of the air/fuel mixture, which favors the increase of engine power and; consequently, reduced the specific fuel consumption.

Hypoxia-Inducible Factor-1α: A Potential Factor for the Enhancement of Osseointegration between Dental Implants and Tissue-Engineered Bone

Directory of Open Access Journals (Sweden)

Duohong Zou

2011-07-01

Full Text Available Introduction: Tissue-engineered bones are widely utilized to protect healthy tissue, reduce pain, and increase the success rate of dental implants. one of the most challenging obstacles lies in obtaining effective os-seointegration between dental implants and tissue-engineered structures. Deficiencies in vascularization, osteogenic factors, oxygen, and other nutrients inside the tissue-engineered bone during the early stages following implantation all inhibit effective osseointe-gration. Oxygen is required for aerobic metabolism in bone and blood vessel tissues, but oxygen levels inside tissue-engineered bone are not suf-ficient for cell proliferation. HIF-1α is a pivotal regulator of hypoxic and ischemic vascular responses, driving transcriptional activation of hundreds of genes involved in vascular reactivity, angiogenesis, arteriogenesis, and osteogenesis.The hypothesis: Hypoxia-Inducible Factor-1α seems a potential factor for the enhancement of osseointegration between dental implants and tissue-engineered bone.Evaluation of the hypothesis: Enhancement of HIF-1α protein expression is recognized as the most promising approach for angiogenesis, because it can induce multiple angiogenic targets in a coordinated manner. Therefore, it will be a novel potential therapeutic methods targeting HIF-1α expression to enhance osseointegration be-tween dental implants and tissue-engineered bone.

Baseline performance and emissions data for a single-cylinder, direct-injected diesel engine

Science.gov (United States)

Dezelick, R. A.; Mcfadden, J. J.; Ream, L. W.; Barrows, R. F.

1983-01-01

Comprehensive fuel consumption, mean effective cylinder pressure, and emission test results for a supercharged, single-cylinder, direct-injected, four-stroke-cycle, diesel test engine are documented. Inlet air-to-exhaust pressure ratios were varied from 1.25 to 3.35 in order to establish the potential effects of turbocharging techniques on engine performance. Inlet air temperatures and pressures were adjusted from 34 to 107 C and from 193 to 414 kPa to determine the effects on engine performance and emissions. Engine output ranged from 300 to 2100 kPa (brake mean effective pressure) in the speed range of 1000 to 3000 rpm. Gaseous and particulate emission rates were measured. Real-time values of engine friction and pumping loop losses were measured independently and compared with motored engine values.

Potential impacts of Brayton and Stirling cycle engines

Science.gov (United States)

Heft, R. C.

1980-01-01

Two engine technologies (Brayton cycle and Stirling cycle) are examined for their potential economic impact and fuel utilization. An economic analysis of the expected response of buyers to the attributes of the alternative engines was performed. Hedonic coefficients for vehicle fuel efficiency, performance and size were estimated for domestic cars based upon historical data. The marketplace value of the fuel efficiency enhancement provided by Brayton or Stirling engines was estimated. Under the assumptions of 10 years for plant conversions and 1990 and 1995 as the introduction data for turbine and Stirling engines respectively, the comparative fuel savings and present value of the future savings in fuel costs were estimated.

Engineering signal peptides for enhanced protein secretion from Lactococcus lactis.

Science.gov (United States)

Ng, Daphne T W; Sarkar, Casim A

2013-01-01

Lactococcus lactis is an attractive vehicle for biotechnological production of proteins and clinical delivery of therapeutics. In many such applications using this host, it is desirable to maximize secretion of recombinant proteins into the extracellular space, which is typically achieved by using the native signal peptide from a major secreted lactococcal protein, Usp45. In order to further increase protein secretion from L. lactis, inherent limitations of the Usp45 signal peptide (Usp45sp) must be elucidated. Here, we performed extensive mutagenesis on Usp45sp to probe the effects of both the mRNA sequence (silent mutations) and the peptide sequence (amino acid substitutions) on secretion. We screened signal peptides based on their resulting secretion levels of Staphylococcus aureus nuclease and further evaluated them for secretion of Bacillus subtilis α-amylase. Silent mutations alone gave an increase of up to 16% in the secretion of α-amylase through a mechanism consistent with relaxed mRNA folding around the ribosome binding site and enhanced translation. Targeted amino acid mutagenesis in Usp45sp, combined with additional silent mutations from the best clone in the initial screen, yielded an increase of up to 51% in maximum secretion of α-amylase while maintaining secretion at lower induction levels. The best sequence from our screen preserves the tripartite structure of the native signal peptide but increases the positive charge of the n-region. Our study presents the first example of an engineered L. lactis signal peptide with a higher secretion yield than Usp45sp and, more generally, provides strategies for further enhancing protein secretion in bacterial hosts.

Effect of engine parameters and type of gaseous fuel on the performance of dual-fuel gas diesel engines. A critical review

Energy Technology Data Exchange (ETDEWEB)

Sahoo, B.B. [Centre for Energy, Indian Institute of Technology, Guwahati 781039 (India); Sahoo, N.; Saha, U.K. [Department of Mechanical Engineering, Indian Institute of Technology, Guwahati 781039 (India)

2009-08-15

Petroleum resources are finite and, therefore, search for their alternative non-petroleum fuels for internal combustion engines is continuing all over the world. Moreover gases emitted by petroleum fuel driven vehicles have an adverse effect on the environment and human health. There is universal acceptance of the need to reduce such emissions. Towards this, scientists have proposed various solutions for diesel engines, one of which is the use of gaseous fuels as a supplement for liquid diesel fuel. These engines, which use conventional diesel fuel and gaseous fuel, are referred to as 'dual-fuel engines'. Natural gas and bio-derived gas appear more attractive alternative fuels for dual-fuel engines in view of their friendly environmental nature. In the gas-fumigated dual-fuel engine, the primary fuel is mixed outside the cylinder before it is inducted into the cylinder. A pilot quantity of liquid fuel is injected towards the end of the compression stroke to initiate combustion. When considering a gaseous fuel for use in existing diesel engines, a number of issues which include, the effects of engine operating and design parameters, and type of gaseous fuel, on the performance of the dual-fuel engines, are important. This paper reviews the research on above issues carried out by various scientists in different diesel engines. This paper touches upon performance, combustion and emission characteristics of dual-fuel engines which use natural gas, biogas, producer gas, methane, liquefied petroleum gas, propane, etc. as gaseous fuel. It reveals that 'dual-fuel concept' is a promising technique for controlling both NO{sub x} and soot emissions even on existing diesel engine. But, HC, CO emissions and 'bsfc' are higher for part load gas diesel engine operations. Thermal efficiency of dual-fuel engines improve either with increased engine speed, or with advanced injection timings, or with increased amount of pilot fuel. The ignition

Determination of performance degradation of a marine diesel engine by using curve based approach

International Nuclear Information System (INIS)

Kökkülünk, Görkem; Parlak, Adnan; Erdem, Hasan Hüseyin

2016-01-01

Highlights: • Mathematical model was developed for a marine diesel engine. • Measurements were taken from Main Engine of M/V Ince Inebolu. • The model was validated for the marine diesel engine. • Curve Based Method was performed to evaluate the performance. • Degradation values of a marine diesel engine were found for power and SFC. - Abstract: Nowadays, energy efficiency measures on ships are the top priority topic for the maritime sector. One of the important key parameters of energy efficiency is to find the useful tool to improve the energy efficiency. There are two steps to improve the energy efficiency on ships: Measurement and Evaluation of performance of main fuel consumers. Performance evaluation is the method that evaluates how much the performance changes owing to engine component degradation which cause to reduce the performance due to wear, fouling, mechanical problems, etc. In this study, zero dimensional two zone combustion model is developed and validated for two stroke marine diesel engine (MITSUI MAN B&W 6S50MC). The measurements are taken from a real ship named M/V Ince Inebolu by the research team during the normal operation of the main engine in the region of the Marmara Sea. To evaluate the performance, “Curve based method” is used to calculate the total performance degradation. This total degradation is classified as parameters of compression pressure, injection timing, injection pressure, scavenge air temperature and scavenge air pressure by means of developed mathematical model. In conclusion, the total degradation of the applied ship is found as 620 kW by power and 26.74 g/kW h by specific fuel consumption.

New perspectives for advanced automobile diesel engines

Science.gov (United States)

Tozzi, L.; Sekar, R.; Kamo, R.; Wood, J. C.

1983-01-01

Computer simulation results are presented for advanced automobile diesel engine performance. Four critical factors for performance enhancement were identified: (1) part load preheating and exhaust gas energy recovery, (2) fast heat release combustion process, (3) reduction in friction, and (4) air handling system efficiency. Four different technology levels were considered in the analysis. Simulation results are compared in terms of brake specific fuel consumption and vehicle fuel economy in km/liter (miles per gallon). Major critical performance sensitivity areas are: (1) combustion process, (2) expander and compressor efficiency, and (3) part load preheating and compound system. When compared to the state of the art direct injection, cooled, automobile diesel engine, the advanced adiabatic compound engine concept showed the unique potential of doubling the fuel economy. Other important performance criteria such as acceleration, emissions, reliability, durability and multifuel capability are comparable to or better than current passenger car diesel engines.

Does Caffeine Enhance Athletic Performance?

Directory of Open Access Journals (Sweden)

Marcou Juliana

2016-04-01

Conclusion: Caffeine consumption may enhance athletic endurance, based on strong evidence, but further research needs to be conducted. High caffeine doses than the optimal, 3-6 mg/kg, before exercise does not confer any additional improvement in athletic performance. Additional, higher caffeine doses may cause side effects in athletes.

Infiltration performance of engineered surfaces commonly used for distributed stormwater management.

Science.gov (United States)

Valinski, N A; Chandler, D G

2015-09-01

Engineered porous media are commonly used in low impact development (LID) structures to mitigate excess stormwater in urban environments. Differences in infiltrability of these LID systems arise from the wide variety of materials used to create porous surfaces and subsequent maintenance, debris loading, and physical damage. In this study, the infiltration capacity of six common materials was tested by multiple replicate experiments with automated mini-disk infiltrometers. The tested materials included porous asphalt, porous concrete, porous brick pavers, flexible porous pavement, engineered soils, and native soils. Porous asphalt, large porous brick pavers, and curb cutout rain gardens showed the greatest infiltration rates. Most engineered porous pavements and soils performed better than the native silt loam soils. Infiltration performance was found to be related more to site design and environmental factors than material choice. Sediment trap zones in both pavements and engineered soil rain gardens were found to be beneficial to the whole site performance. Winter chloride application had a large negative impact on poured in place concrete, making it a poor choice for heavily salted areas. Copyright © 2015 Elsevier Ltd. All rights reserved.

THE EFFECT OF KARANJA OIL METHYL ESTER ON KIRLOSKAR HA394DI DIESEL ENGINE PERFORMANCE AND EXHAUST EMISSIONS

Directory of Open Access Journals (Sweden)

Sharanappa K Godiganur

2010-01-01

Full Text Available Biofuels are being investigated as potential substitutes for current high pollutant fuels obtained from the conventional sources. The primary problem associated with using straight vegetable oil as fuel in a compression ignition engine is caused by viscosity. The process of transesterifiction of vegetable oil with methyl alcohol provides a significant reduction in viscosity, thereby enhancing the physical properties of vegetable oil. The Kirloskar HA394 compression ignition, multi cylinder diesel engine does not require any modification to replace diesel by karanja methyl ester. Biodiesel can be used in its pure form or can be blended with diesel to form different blends. The purpose of this research was to evaluate the potential of karanja oil methyl ester and its blend with diesel from 20% to 80% by volume. Engine performance and exhaust emissions were investigated and compared with the ordinary diesel fuel in a diesel engine. The experimental results show that the engine power of the mixture is closed to the values obtained from diesel fuel and the amounts of exhaust emissions are lower than those of diesel fuel. Hence, it is seen that the blend of karanja ester and diesel fuel can be used as an alternative successfully in a diesel engine without any modification and in terms of emission parameters; it is an environmental friendly fuel

TECHNOLOGIES TO ENHANCE OPERATION OF THE EXISTING NATURAL GAS COMPRESSION INFRASTRUCTURE

Energy Technology Data Exchange (ETDEWEB)

Anthony J. Smalley; Ralph E. Harris; Gary D. Bourn; Danny M. Deffenbaugh

2005-01-01

This quarterly report documents work performed under Tasks 10 through 14 of the project entitled: ''Technologies to Enhance Operation of the Existing Natural Gas Compression Infrastructure''. The project objective is to develop and substantiate methods for operating integral engine/compressors in gas pipeline service, which reduce fuel consumption, increase capacity, and enhance mechanical integrity. The report first documents tests performed on a KVG103 engine/compressor installed at Duke's Thomaston Compressor Station. This is the first series of tests performed on a four-stroke engine under this program. Additionally, this report presents results, which complete a comparison of performance before and after modification to install High Pressure Fuel Injection and a Turbocharger on a GMW10 at Williams Station 60. Quarterly Reports 7 and 8 already presented detailed data from tests before and after this modification, but the final quantitative comparison required some further analysis, which is presented in Section 5 of this report. The report further presents results of detailed geometrical measurements and flow bench testing performed on the cylinders and manifolds of the Laboratory Cooper GMVH6 engine being employed for two-stroke engine air balance investigations. These measurements are required to enhance the detailed accuracy in modeling the dynamic interaction of air manifold, exhaust manifold, and in-cylinder fuel-air balance.

A Historical Review of Cermet Fuel Development and the Engine Performance Implications

Science.gov (United States)

Stewart, Mark E.

2015-01-01

To better understand Cermet engine performance, examined historical material development reports two issues: High vaporization rate of UO2, High temperature chemical stability of UO2. Cladding and chemical stabilizers each result in large, order of magnitude improvements in high temperature performance. Few samples were tested above 2770 K. Results above 2770 K are ambiguous. Contemporary testing may clarify performance. Cermet sample testing during the NERVA Rover era. Important properties, melting temperature, vaporization rate, strength, Brittle-to-Ductile Transition, cermet sample test results, engine performance, location, peak temperature.

A new generation of high performance engines for spacecraft propulsion

Science.gov (United States)

Rosenberg, Sanders D.; Schoenman, Leonard

1991-01-01

Experimental data validating advanced engine designs at three thrust levels (5, 15, and 100 lbF) is presented. All of the three engine designs considered employ a Moog bipropellant torque motor valve, platelet injector design, and iridium-lined rhenium combustion chamber. Attention is focused on the performance, robustness, duration, and flexibility characteristics of the engines. It is noted that the 5- and 15-lbF thrust engines can deliver a steady state specific impulse in excess of 310 lbF-sec/lbm at an area ratio of 150:1, while the 150-lbF thrust engines deliver a steady state specific impulse of 320 lbF-sec/lbm at an area ratio of 250:1. The hot-fire test results reveal specific impulse improvements of 15 to 25 sec over conventional fuel film cooled columbium chamber designs while operating at maximum chamber temperatures.

Numerical Study on the Performance Characteristics of Hydrogen Fueled Port Injection Internal Combustion Engine

OpenAIRE

Rosli A. Bakar; Mohammed K. Mohammed; M. M. Rahman

2009-01-01

This study was focused on the engine performance of single cylinder hydrogen fueled port injection internal combustion engine. GT-Power was utilized to develop the model for port injection engine. One dimensional gas dynamics was represented the flow and heat transfer in the components of the engine model. The governing equations were introduced first, followed by the performance parameters and model description. Air-fuel ratio was varied from stoichiometric limit to a lean limit and the rota...

Impact of higher n-butanol addition on combustion and performance of GDI engine in stoichiometric combustion

International Nuclear Information System (INIS)

Chen, Zheng; Yang, Feng; Xue, Shuo; Wu, Zhenkuo; Liu, Jingping

2015-01-01

Highlights: • Effects of 0–50% n-butanol addition on GDI engine are experimentally studied. • Higher n-butanol fractions increase combustion pressure and fasten burning rate. • Higher n-butanol fractions increase BSFC but improve BTE. • Higher n-butanol fractions enhance combustion stability but increase knock intensity. • Higher n-butanol fractions reduce exhaust temperature and NOx emissions. - Abstract: An experimental study was carried out on a turbocharged gasoline direct injection (GDI) engine fueled by n-butanol/gasoline blends. Effects of n-butanol percents (15%, 30%, and 50%) on combustion and performance of the engine operating on stoichiometric combustion condition were discussed and also compared with pure gasoline in this paper. The results indicate that n-butanol/gasoline blends increase combustion pressure and pressure rise rate, fasten burning rate, and shorten ignition delay and combustion duration, as compared to pure gasoline. Moreover, these trends are impacted more evidently with increased n-butanol fraction in the blends. In addition, higher n-butanol percent of gasoline blends increase combustion temperature but decrease the temperature in the later stage of expansion stroke, which contributes to the control of exhaust temperature at high-load. With regards to engine performance, higher n-butanol percent in the blends results in increased brake specific fuel consumption (BSFC) and higher brake thermal efficiency (BTE). However, higher n-butanol addition helps to improve combustion stability but shows slightly higher knock possibility in high-load. In that case, the knock trend could be weakened by retarding ignition timing. Moreover, higher n-butanol addition significantly decreases NOx emissions, but it increases CO emissions obviously.

Optimum performance characteristics of a solar-driven Stirling heat engine system

International Nuclear Information System (INIS)

Liao, Tianjun; Lin, Jian

2015-01-01

Graphical abstract: T–S diagram of the SHE cycle. - Highlights: • Based on Lagrange multiplier method, the optimal performance are investigated. • The energy balance between the absorber and the hot side of Stirling heat engine is considered. • The effects of major parameters on the optimal performance are investigated. - Abstract: A solar-driven Stirling heat engine system composed of a Stirling heat engine, a solar collector, and a heat sink is presented, in which the radiation and convection heat losses of the solar collector, the heat-leak between the thermal absorber and heat sink, the regenerative losses of the Stirling heat engine, and the energy balance between the thermal absorber and the high isothermal process of the Stirling heat engine are taken into consideration. Based on the irreversible thermodynamics and Lagrange multiplier method, the maximum power output and the corresponding optimal efficiency of the system are determined and the absorber temperature that maximizes the optimal system efficiency is calculated numerically. The influences of some system parameters such as the concentrating ratio, the volume ratio during the regenerative processes and irreversibilities of heat exchange processes on the optimal efficiency are analyzed in details. The results obtained here may provide a new idea to design practical solar-driven Stirling heat engine system

Performance and emission characteristics of diesel engine with COME-Triacetin additive blends as fuel

Energy Technology Data Exchange (ETDEWEB)

Venkateswara Rao, P. [Dept. of Mechanical Engineering, K I T S, Warangal- 506015, A. P. (India); Appa Rao, B.V. [Dept. of Marine Engineering, Andhra University, Visakhapatnam-530003, A. P. (India)

2012-07-01

The Triacetin [C9H14O6] additive is used an anti-knocking agent along with the bio-diesel in DI- diesel engine. In the usage of diesel fuel and neat bio-diesel knocking can be detected to some extent. The T- additive usage in the engine suppressed knocking, improved the performance and reduced tail pipe emissions. Comparative study is conducted using petro-diesel, bio-diesel, and with various additive blends of bio-diesel on DI- diesel engine. Coconut oil methyl ester (COME) is used with additive Triacetin (T) at various percentages by volume for all loads (No load, 25%, 50%, 75% and full load). The performance of engine is compared with neat diesel in respect of engine efficiency, exhaust emissions and combustion knock. Of the five Triacetin- biodiesel blends tried, 10% Triacetin combination with biodiesel proved encouraging in all respects of performance of the engine.

Engineering of Surface Chemistry for Enhanced Sensitivity in Nanoporous Interferometric Sensing Platforms.

Science.gov (United States)

Law, Cheryl Suwen; Sylvia, Georgina M; Nemati, Madieh; Yu, Jingxian; Losic, Dusan; Abell, Andrew D; Santos, Abel

2017-03-15

We explore new approaches to engineering the surface chemistry of interferometric sensing platforms based on nanoporous anodic alumina (NAA) and reflectometric interference spectroscopy (RIfS). Two surface engineering strategies are presented, namely (i) selective chemical functionalization of the inner surface of NAA pores with amine-terminated thiol molecules and (ii) selective chemical functionalization of the top surface of NAA with dithiol molecules. The strong molecular interaction of Au 3+ ions with thiol-containing functional molecules of alkane chain or peptide character provides a model sensing system with which to assess the sensitivity of these NAA platforms by both molecular feature and surface engineering. Changes in the effective optical thickness of the functionalized NAA photonic films (i.e., sensing principle), in response to gold ions, are monitored in real-time by RIfS. 6-Amino-1-hexanethiol (inner surface) and 1,6-hexanedithiol (top surface), the most sensitive functional molecules from approaches i and ii, respectively, were combined into a third sensing strategy whereby the NAA platforms are functionalized on both the top and inner surfaces concurrently. Engineering of the surface according to this approach resulted in an additive enhancement in sensitivity of up to 5-fold compared to previously reported systems. This study advances the rational engineering of surface chemistry for interferometric sensing on nanoporous platforms with potential applications for real-time monitoring of multiple analytes in dynamic environments.

Factors of airplane engine performance

Science.gov (United States)

Gage, Victor R

1921-01-01

This report is based upon an analysis of a large number of airplane-engine tests. It contains the results of a search for fundamental relations between many variables of engine operation. The data used came from over 100 groups of tests made upon several engines, primarily for military information. The types of engines were the Liberty 12 and three models of the Hispano-Suiza. The tests were made in the altitude chamber, where conditions simulated altitudes up to about 30,000 feet, with engine speeds ranging from 1,200 to 2,200 r.p.m. The compression ratios of the different engines ranged from under 5 to over 8 to 1. The data taken on the tests were exceptionally complete, including variations of pressure and temperature, besides the brake and friction torques, rates of fuel and air consumption, the jacket and exhaust heat losses.

Development and Experimental Study of Education Through the Synergetic Training for the Engineering Enhanced Medicine “ESTEEM” in Tohoku University

Science.gov (United States)

Yamano, Masahiro; Matsuki, Noriaki; Numayama, Keiko; Takeda, Motohiro; Hayasaka, Tomoaki; Ishikawa, Takuji; Yamaguchi, Takami

We developed new bio-medical engineering curriculum for industrial engineers, and we confirmed that the engineer's needs and the educative effects by holding a trail program. This study in Tohoku University was supported by the Ministry of Economy, Trade and Industry (METI) . We named the curriculum as “ESTEEM” which is acronym of project title “Education through the Synergetic Training for the Engineering Enhanced Medicine” . In Tohoku University, the “REDEEM” curriculum which is an entry level course of bio-medical engineering for engineers has been already held. The positioning of “ESTEEM” program is an advanced course to enhance knowledge and experience in clinical point of view. The program is consisted of the problem based learning (PBL) style lectures, practical training, and observation learning in hospital. It is a unique opportunity to have instruction by doctors, from diagnosis to surgical operation, from traditional technique to front-line medical equipment. In this paper, we report and discuss on the progress of the new bio-medical engineering curriculum.

THE EFFECTS OF INCREASE THE COMPRESSION RATIO ON PERFORMANCE OF A DIESEL ENGINE

Directory of Open Access Journals (Sweden)

Adnan PARLAK

2003-02-01

Full Text Available An optimisation of the Diesel cycle has been performed for power output and thermal efficiency with respect to compression ratio for various extreme temperature ratio. The relation between compression ratio and extreme temperature ratio, which gives optimum performance is derived. As the compression ratio of the diesel engine is increased in comparison to the optimum value of the engine, it is shown that the performance of the engine is decreased. The experimental study agrees with these results. In this study, compression ratio of a single cylinder pre-combustion chamber variable compression ratio Ricardo E6 type engine with the optimum compression ratio of 18.20 was increased to 19.60. As a results of this increase, specific fuel consumption was increased about 8 % and brake thermal efficiency was decreased about 7.5 %.

A framework to improve performance measurement in engineering projects

OpenAIRE

Zheng , Li; Baron , Claude; Esteban , Philippe; Xue , Rui; Zhang , Qiang

2017-01-01

International audience; A wide range of methods and good practices have been developed for the measurement of projects performance. They help project managers to effectively monitor the project progress and evaluate results. However, from a literature review, we noticed several remaining critical issues in measuring projects performance, such as an unbalanced development of Key Performance Indicators types between lagging and leading indicators. On the other hand, systems engineering measurem...

Impact of Dissociation and Sensible Heat Release on Pulse Detonation and Gas Turbine Engine Performance

Science.gov (United States)

Povinelli, Louis A.

2001-01-01

A thermodynamic cycle analysis of the effect of sensible heat release on the relative performance of pulse detonation and gas turbine engines is presented. Dissociation losses in the PDE (Pulse Detonation Engine) are found to cause a substantial decrease in engine performance parameters.

Criterion for the engineering performance of carbon materials under neutron irradiation

International Nuclear Information System (INIS)

Virgil'ev, Yu.S.

2002-01-01

The criterion for the engineering performance and substation of its applicability to the reactor graphite are proposed. The complex indicator, representing the ratio of strength limits by compression and bending is proposed as the above criterion, characterizing the graphite quality. The growth of this criterion indicates the accumulation of large heterogeneities microcracks of technological or radiation character. The decrease in this indicator testifies to the growth of small heterogeneities, and consequently to the increase in the graphite engineering performance [ru

Performance Evaluation of the T6 Ion Engine

Science.gov (United States)

Snyder, John Steven; Goebel, Dan M.; Hofer, Richard R.; Polk, James E.; Wallace, Neil C.; Simpson, Huw

2010-01-01

The T6 ion engine is a 22-cm diameter, 4.5-kW Kaufman-type ion thruster produced by QinetiQ, Ltd., and is baselined for the European Space Agency BepiColombo mission to Mercury and is being qualified under ESA sponsorship for the extended range AlphaBus communications satellite platform. The heritage of the T6 includes the T5 ion thruster now successfully operating on the ESA GOCE spacecraft. As a part of the T6 development program, an engineering model thruster was subjected to a suite of performance tests and plume diagnostics at the Jet Propulsion Laboratory. The engine was mounted on a thrust stand and operated over its nominal throttle range of 2.5 to 4.5 kW. In addition to the typical electrical and flow measurements, an E x B mass analyzer, scanning Faraday probe, thrust vector probe, and several near-field probes were utilized. Thrust, beam divergence, double ion content, and thrust vector movement were all measured at four separate throttle points. The engine performance agreed well with published data on this thruster. At full power the T6 produced 143 mN of thrust at a specific impulse of 4120 seconds and an efficiency of 64%; optimization of the neutralizer for lower flow rates increased the specific impulse to 4300 seconds and the efficiency to nearly 66%. Measured beam divergence was less than, and double ion content was greater than, the ring-cusp-design NSTAR thruster that has flown on NASA missions. The measured thrust vector offset depended slightly on throttle level and was found to increase with time as the thruster approached thermal equilibrium.

An experimental investigation on engine performance and emissions of a supercharged H{sub 2}-diesel dual-fuel engine

Energy Technology Data Exchange (ETDEWEB)

Roy, Murari Mohon [Rajshahi University of Engineering and Technology (JSPS Research Fellow, Okayama University), Tsushima-Naka 3, Okayama 700-8530 (Japan); Department of Mechanical Engineering, Okayama University, Tsushima-Naka 3, Okayama 700-8530 (Japan); Tomita, Eiji; Kawahara, Nobuyuki; Harada, Yuji [Department of Mechanical Engineering, Okayama University, Tsushima-Naka 3, Okayama 700-8530 (Japan); Sakane, Atsushi [Mitsui Engineering and Shipbuilding Co. Ltd., 6-4 Tsukiji 5-chome, Chuo-ku, Tokyo (Japan)

2010-01-15

This study investigated the engine performance and emissions of a supercharged engine fueled by hydrogen and ignited by a pilot amount of diesel fuel in dual-fuel mode. The engine was tested for use as a cogeneration engine, so power output while maintaining a reasonable thermal efficiency was important. Experiments were carried out at a constant pilot injection pressure and pilot quantity for different fuel-air equivalence ratios and at various injection timings without and with charge dilution. The experimental strategy was to optimize the injection timing to maximize engine power at different fuel-air equivalence ratios without knocking and within the limit of the maximum cylinder pressure. The engine was tested first with hydrogen-operation condition up to the maximum possible fuel-air equivalence ratio of 0.3. A maximum IMEP of 908 kPa and a thermal efficiency of about 42% were obtained. Equivalence ratio could not be further increased due to knocking of the engine. The emission of CO was only about 5 ppm, and that of HC was about 15 ppm. However, the NOx emissions were high, 100-200 ppm or more. The charge dilution by N{sub 2} was then performed to obtain lower NOx emissions. The 100% reduction of NOx was achieved. Due to the dilution by N{sub 2} gas, higher amount of energy could be supplied from hydrogen without knocking, and about 13% higher IMEP was produced than without charge dilution. (author)

Intake plenum volume and its influence on the engine performance, cyclic variability and emissions

International Nuclear Information System (INIS)

Ceviz, M.A.

2007-01-01

Intake manifold connects the intake system to the intake valve of the engine and through which air or air-fuel mixture is drawn into the cylinder. Details of the flow in intake manifolds are extremely complex. Recently, most of engine companies are focused on variable intake manifold technology due to their improvement on engine performance. This paper investigates the effects of intake plenum volume variation on engine performance and emissions to constitute a base study for variable intake plenum. Brake and indicated engine performance characteristics, coefficient of variation in indicated mean effective pressure (COV imep ) as an indicator for cyclic variability, pulsating flow pressure in the intake manifold runner, and CO, CO 2 and HC emissions were taken into consideration to evaluate the effects of different plenum volumes. The results of this study showed that the variation in the plenum volume causes an improvement on the engine performance and the pollutant emissions. The brake torque and related performance characteristics improved pronouncedly about between 1700 and 2600 rpm by increasing plenum volume. Additionally, although the increase in the plenum volume caused the mixture leaner due to the increase in the intake runner pressure and lean mixtures inclined to increase the cyclic variability, a decrease was interestingly observed in the COV imep

Electroactive biodegradable polyurethane significantly enhanced Schwann cells myelin gene expression and neurotrophin secretion for peripheral nerve tissue engineering.

Science.gov (United States)

Wu, Yaobin; Wang, Ling; Guo, Baolin; Shao, Yongpin; Ma, Peter X

2016-05-01

Myelination of Schwann cells (SCs) is critical for the success of peripheral nerve regeneration, and biomaterials that can promote SCs' neurotrophin secretion as scaffolds are beneficial for nerve repair. Here we present a biomaterials-approach, specifically, a highly tunable conductive biodegradable flexible polyurethane by polycondensation of poly(glycerol sebacate) and aniline pentamer, to significantly enhance SCs' myelin gene expression and neurotrophin secretion for peripheral nerve tissue engineering. SCs are cultured on these conductive polymer films, and the biocompatibility of these films and their ability to enhance myelin gene expressions and sustained neurotrophin secretion are successfully demonstrated. The mechanism of SCs' neurotrophin secretion on conductive films is demonstrated by investigating the relationship between intracellular Ca(2+) level and SCs' myelination. Furthermore, the neurite growth and elongation of PC12 cells are induced by adding the neurotrophin medium suspension produced from SCs-laden conductive films. These data suggest that these conductive degradable polyurethanes that enhance SCs' myelin gene expressions and sustained neurotrophin secretion perform great potential for nerve regeneration applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Performance enhancement of hermetic compressor using phase change materials

Science.gov (United States)

Mahmoud, I. M.; Rady, M. A.; Huzayyin, A. S.

2015-08-01

The present study is motivated by the need for the research of simple measures for increasing energy efficiency of hermetic compressor. The measure is the application of phase change materials for performance enhancement. The first experimental study should be guide for choice of PCM. It has been performed to investigate the effects of thermostat setting temperature on the performance of hermetic compressor. The effects of thermostat setting temperature with and without load on power consumption have been analyzed. Performance enhancement using phase change materials (PCMs) has been studied by employing a phase change material Rubitherm-42 (RT-42) on the top surface of compressor. Choice of PCM material is based on basic compressor performance measured in the first part of the present study. Experiments have been carried out for different load values and different quantities of PCM. The quantity and phase change characteristic of PCM are essential parameters that determine the percentage of performance enhancement in term of energy consumption. Reduction of energy consumption of about 10% has been achieved in the present study by using PCM. The present study shows that how to reduce the electrical power consumption to enhance compressor heat dissipation method to improve efficiency.

Automotive Control Systems: For Engine, Driveline, and Vehicle

Science.gov (United States)

Kiencke, Uwe; Nielsen, Lars

Advances in automotive control systems continue to enhance safety and comfort and to reduce fuel consumption and emissions. Reflecting the trend to optimization through integrative approaches for engine, driveline, and vehicle control, this valuable book enables control engineers to understand engine and vehicle models necessary for controller design, and also introduces mechanical engineers to vehicle-specific signal processing and automatic control. The emphasis on measurement, comparisons between performance and modeling, and realistic examples derive from the authors' unique industrial experience

Enhancement of myocardial regeneration through genetic engineering of cardiac progenitor cells expressing Pim-1 kinase.

Science.gov (United States)

Fischer, Kimberlee M; Cottage, Christopher T; Wu, Weitao; Din, Shabana; Gude, Natalie A; Avitabile, Daniele; Quijada, Pearl; Collins, Brett L; Fransioli, Jenna; Sussman, Mark A

2009-11-24

Despite numerous studies demonstrating the efficacy of cellular adoptive transfer for therapeutic myocardial regeneration, problems remain for donated cells with regard to survival, persistence, engraftment, and long-term benefits. This study redresses these concerns by enhancing the regenerative potential of adoptively transferred cardiac progenitor cells (CPCs) via genetic engineering to overexpress Pim-1, a cardioprotective kinase that enhances cell survival and proliferation. Intramyocardial injections of CPCs overexpressing Pim-1 were given to infarcted female mice. Animals were monitored over 4, 12, and 32 weeks to assess cardiac function and engraftment of Pim-1 CPCs with echocardiography, in vivo hemodynamics, and confocal imagery. CPCs overexpressing Pim-1 showed increased proliferation and expression of markers consistent with cardiogenic lineage commitment after dexamethasone exposure in vitro. Animals that received CPCs overexpressing Pim-1 also produced greater levels of cellular engraftment, persistence, and functional improvement relative to control CPCs up to 32 weeks after delivery. Salutary effects include reduction of infarct size, greater number of c-kit(+) cells, and increased vasculature in the damaged region. Myocardial repair is significantly enhanced by genetic engineering of CPCs with Pim-1 kinase. Ex vivo gene delivery to enhance cellular survival, proliferation, and regeneration may overcome current limitations of stem cell-based therapeutic approaches.

Strong Photoluminescence Enhancement of Silicon Oxycarbide through Defect Engineering

Directory of Open Access Journals (Sweden)

Brian Ford

2017-04-01

Full Text Available The following study focuses on the photoluminescence (PL enhancement of chemically synthesized silicon oxycarbide (SiCxOy thin films and nanowires through defect engineering via post-deposition passivation treatments. SiCxOy materials were deposited via thermal chemical vapor deposition (TCVD, and exhibit strong white light emission at room-temperature. Post-deposition passivation treatments were carried out using oxygen, nitrogen, and forming gas (FG, 5% H2, 95% N2 ambients, modifying the observed white light emission. The observed white luminescence was found to be inversely related to the carbonyl (C=O bond density present in the films. The peak-to-peak PL was enhanced ~18 and ~17 times for, respectively, the two SiCxOy matrices, oxygen-rich and carbon-rich SiCxOy, via post-deposition passivations. Through a combinational and systematic Fourier transform infrared spectroscopy (FTIR and PL study, it was revealed that proper tailoring of the passivations reduces the carbonyl bond density by a factor of ~2.2, corresponding to a PL enhancement of ~50 times. Furthermore, the temperature-dependent and temperature-dependent time resolved PL (TDPL and TD-TRPL behaviors of the nitrogen and forming gas passivated SiCxOy thin films were investigated to acquire further insight into the ramifications of the passivation on the carbonyl/dangling bond density and PL yield.

Performance engineering challenges: the view from RENCI

International Nuclear Information System (INIS)

Fowler, R; Gamblin, T; Porterfield, A; Dreher, P; Huang, S; Joo, B

2008-01-01

Trends in chip technology and system design are causing a revolution in high-performance computing. The emergence of multicore processor chips, the construction of very large computing systems, and the increasing need to deal with power and energy issues in these systems are three of the most significant changes. We focus on the way that these trends have created a new set of challenges in the area of performance engineering, the measurement, analysis, and tuning of computing systems and applications. We discuss these changes and outline recent work at the Renaissance Computing Institute to meet these challenges

Machine performance assessment and enhancement for a hexapod machine

Energy Technology Data Exchange (ETDEWEB)

Mou, J.I. [Arizona State Univ., Tempe, AZ (United States); King, C. [Sandia National Labs., Livermore, CA (United States). Integrated Manufacturing Systems Center

1998-03-19

The focus of this study is to develop a sensor fused process modeling and control methodology to model, assess, and then enhance the performance of a hexapod machine for precision product realization. Deterministic modeling technique was used to derive models for machine performance assessment and enhancement. Sensor fusion methodology was adopted to identify the parameters of the derived models. Empirical models and computational algorithms were also derived and implemented to model, assess, and then enhance the machine performance. The developed sensor fusion algorithms can be implemented on a PC-based open architecture controller to receive information from various sensors, assess the status of the process, determine the proper action, and deliver the command to actuators for task execution. This will enhance a hexapod machine`s capability to produce workpieces within the imposed dimensional tolerances.

78 FR 50412 - California State Nonroad Engine Pollution Control Standards; Amendments to Spark Ignition Marine...

Science.gov (United States)

2013-08-19

... Engine Pollution Control Standards; Amendments to Spark Ignition Marine Engine and Boat Regulations... emission standards; enhanced evaporative emission controls for high performance sterndrive/inboard engines... requirement relating to the control of emissions from new nonroad engines which are used in construction...

Engineering Enhanced Vaccine Cell Lines To Eradicate Vaccine-Preventable Diseases: the Polio End Game.

Science.gov (United States)

van der Sanden, Sabine M G; Wu, Weilin; Dybdahl-Sissoko, Naomi; Weldon, William C; Brooks, Paula; O'Donnell, Jason; Jones, Les P; Brown, Cedric; Tompkins, S Mark; Oberste, M Steven; Karpilow, Jon; Tripp, Ralph A

2016-02-15

Vaccine manufacturing costs prevent a significant portion of the world's population from accessing protection from vaccine-preventable diseases. To enhance vaccine production at reduced costs, a genome-wide RNA interference (RNAi) screen was performed to identify gene knockdown events that enhanced poliovirus replication. Primary screen hits were validated in a Vero vaccine manufacturing cell line using attenuated and wild-type poliovirus strains. Multiple single and dual gene silencing events increased poliovirus titers >20-fold and >50-fold, respectively. Host gene knockdown events did not affect virus antigenicity, and clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9-mediated knockout of the top candidates dramatically improved viral vaccine strain production. Interestingly, silencing of several genes that enhanced poliovirus replication also enhanced replication of enterovirus 71, a clinically relevant virus to which vaccines are being targeted. The discovery that host gene modulation can markedly increase virus vaccine production dramatically alters mammalian cell-based vaccine manufacturing possibilities and should facilitate polio eradication using the inactivated poliovirus vaccine. Using a genome-wide RNAi screen, a collection of host virus resistance genes was identified that, upon silencing, increased poliovirus and enterovirus 71 production by from 10-fold to >50-fold in a Vero vaccine manufacturing cell line. This report provides novel insights into enterovirus-host interactions and describes an approach to developing the next generation of vaccine manufacturing through engineered vaccine cell lines. The results show that specific gene silencing and knockout events can enhance viral titers of both attenuated (Sabin strain) and wild-type polioviruses, a finding that should greatly facilitate global implementation of inactivated polio vaccine as well as further reduce costs for live-attenuated oral polio vaccines. This work

Performance Engineering Technology for Scientific Component Software

Energy Technology Data Exchange (ETDEWEB)

Malony, Allen D.

2007-05-08

Large-scale, complex scientific applications are beginning to benefit from the use of component software design methodology and technology for software development. Integral to the success of component-based applications is the ability to achieve high-performing code solutions through the use of performance engineering tools for both intra-component and inter-component analysis and optimization. Our work on this project aimed to develop performance engineering technology for scientific component software in association with the DOE CCTTSS SciDAC project (active during the contract period) and the broader Common Component Architecture (CCA) community. Our specific implementation objectives were to extend the TAU performance system and Program Database Toolkit (PDT) to support performance instrumentation, measurement, and analysis of CCA components and frameworks, and to develop performance measurement and monitoring infrastructure that could be integrated in CCA applications. These objectives have been met in the completion of all project milestones and in the transfer of the technology into the continuing CCA activities as part of the DOE TASCS SciDAC2 effort. In addition to these achievements, over the past three years, we have been an active member of the CCA Forum, attending all meetings and serving in several working groups, such as the CCA Toolkit working group, the CQoS working group, and the Tutorial working group. We have contributed significantly to CCA tutorials since SC'04, hosted two CCA meetings, participated in the annual ACTS workshops, and were co-authors on the recent CCA journal paper [24]. There are four main areas where our project has delivered results: component performance instrumentation and measurement, component performance modeling and optimization, performance database and data mining, and online performance monitoring. This final report outlines the achievements in these areas for the entire project period. The submitted progress

PERFORMANCE EVALUATION OF EXTERNAL MIXTURE FORMATION STRATEGY IN HYDROGEN-FUELED ENGINE

OpenAIRE

Mohammed Kamil; M. M. Rahman; Rosli A. Bakar

2011-01-01

Mohammed Kamil1, M. M. Rahman2 and Rosli A. Bakar2Hydrogen induction strategy in an internal combustion engine plays a vital role in increasing the power density and prohibiting combustion anomalies. This paper inspects the performance characteristics of cylinder hydrogen-fueled engine with port injection feeding strategy. To that end, a one-dimensional gas dynamic model has been built to represent the flow and heat transfer in the components of the engine. The governing equations are introdu...

Analytical Modelling of the Effects of Different Gas Turbine Cooling Techniques on Engine Performance =

Science.gov (United States)

Uysal, Selcuk Can

In this research, MATLAB SimulinkRTM was used to develop a cooled engine model for industrial gas turbines and aero-engines. The model consists of uncooled on-design, mean-line turbomachinery design and a cooled off-design analysis in order to evaluate the engine performance parameters by using operating conditions, polytropic efficiencies, material information and cooling system details. The cooling analysis algorithm involves a 2nd law analysis to calculate losses from the cooling technique applied. The model is used in a sensitivity analysis that evaluates the impacts of variations in metal Biot number, thermal barrier coating Biot number, film cooling effectiveness, internal cooling effectiveness and maximum allowable blade temperature on main engine performance parameters of aero and industrial gas turbine engines. The model is subsequently used to analyze the relative performance impact of employing Anti-Vortex Film Cooling holes (AVH) by means of data obtained for these holes by Detached Eddy Simulation-CFD Techniques that are valid for engine-like turbulence intensity conditions. Cooled blade configurations with AVH and other different external cooling techniques were used in a performance comparison study. (Abstract shortened by ProQuest.).

Uprated OMS Engine Status-Sea Level Testing Results

Science.gov (United States)

Bertolino, J. D.; Boyd, W. C.

1990-01-01

The current Space Shuttle Orbital Maneuvering Engine (OME) is pressure fed, utilizing storable propellants. Performance uprating of this engine, through the use of a gas generator driven turbopump to increase operating pressure, is being pursued by the NASA Johnson Space Center (JSC). Component level design, fabrication, and test activities for this engine system have been on-going since 1984. More recently, a complete engine designated the Integrated Component Test Bed (ICTB), was tested at sea level conditions by Aerojet. A description of the test hardware and results of the sea level test program are presented. These results, which include the test condition operating envelope and projected performance at altitude conditions, confirm the capability of the selected Uprated OME (UOME) configuration to meet or exceed performance and operational requirements. Engine flexibility, demonstrated through testing at two different operational mixture ratios, along with a summary of projected Space Shuttle performance enhancements using the UOME, are discussed. Planned future activities, including ICTB tests at simulated altitude conditions, and recommendations for further engine development, are also discussed.

Systems Engineering Knowledge Asset (SEKA) Management for Higher Performing Engineering Teams: People, Process and Technology toward Effective Knowledge-Workers

Science.gov (United States)

Shelby, Kenneth R., Jr.

2013-01-01

Systems engineering teams' value-creation for enterprises is slower than possible due to inefficiencies in communication, learning, common knowledge collaboration and leadership conduct. This dissertation outlines the surrounding people, process and technology dimensions for higher performing engineering teams. It describes a true experiment…

Enhancing the light-driven production of D-lactate by engineering cyanobacterium using a combinational strategy

Science.gov (United States)

Li, Chao; Tao, Fei; Ni, Jun; Wang, Yu; Yao, Feng; Xu, Ping

2015-05-01

It is increasingly attractive to engineer cyanobacteria for bulk production of chemicals from CO2. However, cofactor bias of cyanobacteria is different from bacteria that prefer NADH, which hampers cyanobacterial strain engineering. In this study, the key enzyme D-lactate dehydrogenase (LdhD) from Lactobacillus bulgaricus ATCC11842 was engineered to reverse its favored cofactor from NADH to NADPH. Then, the engineered enzyme was introduced into Synechococcus elongatus PCC7942 to construct an efficient light-driven system that produces D-lactic acid from CO2. Mutation of LdhD drove a fundamental shift in cofactor preference towards NADPH, and increased D-lactate productivity by over 3.6-fold. We further demonstrated that introduction of a lactic acid transporter and bubbling CO2-enriched air also enhanced D-lactate productivity. Using this combinational strategy, increased D-lactate concentration and productivity were achieved. The present strategy may also be used to engineer cyanobacteria for producing other useful chemicals.

Performance evaluation of a diesel engine using biodiesel

International Nuclear Information System (INIS)

Shahid, E.M.; Jamal, Y.

2011-01-01

This article is a comparative study of use of mineral diesel and biodiesel derived from cotton seed oil of Pakistani origin. The main problems associated with biodiesel are, its very high viscosity and specific gravity, which are due to long chain triglyceride esters with free fatty acids. The esters are converted into simple structure mono-glycerides esters via transesterification process. The experiments were carried out using blends of diesel and biodiesel with different ratios, to investigate the performance characteristics of engine and exhaust emissions. The experimental results show that the engine using B100 resulting in about 10% higher brake specific fuel consumption and about 10% lower brake thermal efficiency as compared to the use of B0. The engine emissions were almost free from SO/sub x/, having reduced amount of CO, CO/sub 2/0, and THC, but having higher amount of NOx, when B100 was used as fuel. The fuel is becoming more popular due to the reduction in nasty pollutant emissions. (author)

Enhancing nuclear power plant performance through the use of artificial intelligence

International Nuclear Information System (INIS)

Maren, A.J.; Miller, L.F.; Tsoukalas, L.H.; Uhrig, R.E.; Upadhyaya, B.R.

1990-01-01

The objective of this research is to advance the state-of-the-art of applying artificial intelligence technology (both expert systems and neural networks) to enhancing the performance (safety, efficiency, control and management) of nuclear power plants. A second, but equally important, objective is to build a broadly based critical mass of expertise in the artificial intelligence field that can be brought to bear on the technology of nuclear power plants. This means the production of graduates at the B.S., M.S., and Ph.D. levels in Nuclear Engineering and related fields. The research undertaken for this program is particularly appropriate for the M.S. theses and Ph.D. dissertations. A third objective is to transfer the technology developed to the ''nuclear power community,'' as well as the ''scientific and technological community,'' through publications in appropriate journals and proceedings and through presentations at national and international meetings

Performance and emissions of an engine fuelled by biogas of palm oil mill effluent

Science.gov (United States)

Arjuna, J.; Sitorus, T. B.; Ambarita, H.; Abda, S.

2018-02-01

This research investigates the performance and emissions of an engine by biogas and gasoline. The experiments use biogas of palm oil mill effluent (POME) with turbocharger at engine loading conditions (100, 200, 300, 400, and 500 Watt). Specific fuel consumption and thermal efficiency are used to compare engine performance, and emission analysis is based on parameters such as carbon monoxide (CO), hydrocarbon (HC), carbon dioxide (CO2) and oxide (O2). The experimental data show that the maximum thermal efficiency when engine use biogas and gasoline is 20.44% and 22.22% respectively. However, there was CO emission reduction significantly when the engine using POME biogas.

Performance and heat release analysis of a pilot-ignited natural gas engine

Energy Technology Data Exchange (ETDEWEB)

Krishnan, S.R.; Biruduganti, M.; Mo, Y.; Bell, S.R.; Midkiff, K.C. [Alabama Univ., Dept. of Mechanical Engineering, Tuscaloosa, AL (United States)

2002-09-01

The influence of engine operating variables on the performance, emissions and heat release in a compression ignition engine operating in normal diesel and dual-fuel modes (with natural gas fuelling) was investigated. Substantial reductions in NO{sub x} emissions were obtained with dual-fuel engine operation. There was a corresponding increase in unburned hydrocarbon emissions as the substitution of natural gas was increased. Brake specific energy consumption decreased with natural gas substitution at high loads but increased at low loads. Experimental results at fixed pilot injection timing have also established the importance of intake manifold pressure and temperature in improving dual-fuel performance and emissions at part load. (Author)

Performance of a cycle diesel engine fed with biodiesel (B100)

Energy Technology Data Exchange (ETDEWEB)

Volpato, Carlos Eduardo Silva; Barbosa, Jackson Antonio; Salvador, Nilson [Universidade Federal de Lavras (UFLA), MG (Brazil). Dept. de Engenharia], E-mails: volpato@ufla.br, salvador@ufla.br; Conde, Alexon do Prado [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil)], E-mail: alconde@cemig.com.br

2008-07-01

The objective of this work was to evaluate the performance of a cycle diesel engine using soybean biodiesel (B100) in relation to mineral oil diesel. The work was performed at the Department of Engineering at the Federal University of Lavras (UFLA), in Lavras, in the State of Minas Gerais, Brazil, in May, 2007. The parameters analyzed were: effective and reduced power, torque, specific and energy consumption of fuel, efficiency term-mechanics and volumetric. The experiments were installed in an experimental delineation entirely randomized arranged in factorial scheme followed by ANOVA analysis and Tukey test at the level of 5% of probability. There were studied five rotation levels in four repetitions. The results showed the viability of operation of a cycle diesel engine with substitute fuels such as soybean B100. (author)

Design Principles and Concepts for Enhancing Long-Term Cap Performance and Confidence

International Nuclear Information System (INIS)

Steven J. Piet; Robert P. Breckenridge; Gregory J. White; Jacob J. Jacobson; Hilary I. Inyang

2005-01-01

The siting of new landfills is becoming increasing difficult as the public and stakeholders want more confidence of performance for longer times and landfill owners want to store more waste in the least area while knowing and limiting their long-term liabilities. These changes motivate re-examination of long-term performance mechanisms and their implications for cap and barrier designs. Accordingly, in this paper we first consider design principles from the standpoint of long-term performance and management, including the ability to monitor and repair barriers. We then consider some design concepts that may implement these principles, especially evapo-transpiration (ET) caps. We suggest five design principles based on experience in the cap and barrier field as well as other engineering disciplines. These principles are as follows: (1) Establish a clear and defendable design basis. (2) Design for ease of monitoring and repair. (3) Analyze the barrier as a dynamic system, not static. (4) Work with nature, not against. (5) Recognize that increased complexity can reduce, not enhance, net performance. ET caps are an excellent embodiment of these design principles. We apply the design principles to ET caps, as well as variants such as erosion armor, capillary breaks, bio-intrusion layers, and low permeability material layers

Thermal analysis of the effect of thick thermal barrier coatings on diesel engine performance

International Nuclear Information System (INIS)

Hoag, K.L.; Frisch, S.R.; Yonushonis, T.M.

1986-01-01

The reduction of heat rejection from the diesel engine combustion chamber has been the subject of a great deal of focus in recent years. In the pursuit of this goal, Cummins Engine Company has received a contract from the Department of Energy for the development of thick thermal barrier coatings for combustion chamber surfaces. This contract involves the analysis of the impact of coatings on diesel engine performance, bench test evaluation of various coating designs, and single cylinder engine tests. The efforts reported in this paper center on the analysis of the effects of coatings on engine performance and heat rejection. For this analysis the conventional water cooled engine was compared with an engine having limited oil cooling, and utilizing zirocnia coated cylinder had firedecks and piston crowns. The analysis showed little or no benefits of similarly coating the valves or cylinder liner

Development and Performance Verification of Fiber Optic Temperature Sensors in High Temperature Engine Environments

Science.gov (United States)

Adamovsky, Grigory; Mackey, Jeffrey R.; Kren, Lawrence A.; Floyd, Bertram M.; Elam, Kristie A.; Martinez, Martel

2014-01-01

A High Temperature Fiber Optic Sensor (HTFOS) has been developed at NASA Glenn Research Center for aircraft engine applications. After fabrication and preliminary in-house performance evaluation, the HTFOS was tested in an engine environment at NASA Armstrong Flight Research Center. The engine tests enabled the performance of the HTFOS in real engine environments to be evaluated along with the ability of the sensor to respond to changes in the engine's operating condition. Data were collected prior, during, and after each test in order to observe the change in temperature from ambient to each of the various test point levels. An adequate amount of data was collected and analyzed to satisfy the research team that HTFOS operates properly while the engine was running. Temperature measurements made by HTFOS while the engine was running agreed with those anticipated.

A Framework for Performing Verification and Validation in Reuse Based Software Engineering

Science.gov (United States)

Addy, Edward A.

1997-01-01

Verification and Validation (V&V) is currently performed during application development for many systems, especially safety-critical and mission- critical systems. The V&V process is intended to discover errors, especially errors related to critical processing, as early as possible during the development process. The system application provides the context under which the software artifacts are validated. This paper describes a framework that extends V&V from an individual application system to a product line of systems that are developed within an architecture-based software engineering environment. This framework includes the activities of traditional application-level V&V, and extends these activities into domain engineering and into the transition between domain engineering and application engineering. The framework includes descriptions of the types of activities to be performed during each of the life-cycle phases, and provides motivation for the activities.

Study on Fault Diagnostics of a Turboprop Engine Using Inverse Performance Model and Artificial Intelligent Methods

Science.gov (United States)

Kong, Changduk; Lim, Semyeong

2011-12-01

Recently, the health monitoring system of major gas path components of gas turbine uses mostly the model based method like the Gas Path Analysis (GPA). This method is to find quantity changes of component performance characteristic parameters such as isentropic efficiency and mass flow parameter by comparing between measured engine performance parameters such as temperatures, pressures, rotational speeds, fuel consumption, etc. and clean engine performance parameters without any engine faults which are calculated by the base engine performance model. Currently, the expert engine diagnostic systems using the artificial intelligent methods such as Neural Networks (NNs), Fuzzy Logic and Genetic Algorithms (GAs) have been studied to improve the model based method. Among them the NNs are mostly used to the engine fault diagnostic system due to its good learning performance, but it has a drawback due to low accuracy and long learning time to build learning data base if there are large amount of learning data. In addition, it has a very complex structure for finding effectively single type faults or multiple type faults of gas path components. This work builds inversely a base performance model of a turboprop engine to be used for a high altitude operation UAV using measured performance data, and proposes a fault diagnostic system using the base engine performance model and the artificial intelligent methods such as Fuzzy logic and Neural Network. The proposed diagnostic system isolates firstly the faulted components using Fuzzy Logic, then quantifies faults of the identified components using the NN leaned by fault learning data base, which are obtained from the developed base performance model. In leaning the NN, the Feed Forward Back Propagation (FFBP) method is used. Finally, it is verified through several test examples that the component faults implanted arbitrarily in the engine are well isolated and quantified by the proposed diagnostic system.

Impact of Fire Resistant Fuel Blends on Compression Ignition Engine Performance

Science.gov (United States)

2011-07-01

exhaust backpressure .  Emissions are sampled from an exhaust probe installed between the engine and exhaust system butterfly valve.  Crankcase...1  3.0  EFFECTS ON ENGINE PERFORMANCE...fuel as it is heated, effectively limiting oxygen available to combust with the fuel. The research program ended in 1987 without the FRF blend

Personal Vision: Enhancing Work Engagement and the Retention of Women in the Engineering Profession

Directory of Open Access Journals (Sweden)

Kathleen Relihan Buse

2014-12-01

Full Text Available This study examines how personal vision enhances work engagement and the retention of women in the engineering profession. Using a mixed method approach to understand the factors related to the retention of women in the engineering profession, we first interviewed women who persisted and women who opted out of the profession (Buse & Bilimoria, 2014. In these rich stories we found that women who persisted had a personal vision that included their profession, and that this personal vision enabled them to overcome the bias, barriers and discrimination in the engineering workplace. To validate this finding on a larger population, we developed a scale to measure one’s personal vision conceptualized as the ideal self (Boyatzis & Akrivou, 2006. The measure was tested in a pilot study and then used in a study of 495 women with engineering degrees. The findings validate that the ideal self is comprised of self efficacy, hope, optimism and core identity. For these women the ideal self directly impacts work engagement and work engagement directly impacts career commitment to engineering. The findings add to extant theory related to the role of personal vision and intentional change theory. From a practical perspective these findings will aid efforts to retain women in engineering and other STEM professions.

Personal vision: enhancing work engagement and the retention of women in the engineering profession.

Science.gov (United States)

Buse, Kathleen R; Bilimoria, Diana

2014-01-01

This study examines how personal vision enhances work engagement and the retention of women in the engineering profession. Using a mixed method approach to understand the factors related to the retention of women in the engineering profession, we first interviewed women who persisted and women who opted out of the profession (Buse and Bilimoria, 2014). In these rich stories, we found that women who persisted had a personal vision that included their profession, and that this personal vision enabled them to overcome the bias, barriers and discrimination in the engineering workplace. To validate this finding on a larger population, we developed a scale to measure one's personal vision conceptualized as the ideal self (Boyatzis and Akrivou, 2006). The measure was tested in a pilot study and then used in a study of 495 women with engineering degrees. The findings validate that the ideal self is comprised of self-efficacy, hope, optimism and core identity. For these women, the ideal self directly impacts work engagement and work engagement directly impacts career commitment to engineering. The findings add to extant theory related to the role of personal vision and intentional change theory. From a practical perspective, these findings will aid efforts to retain women in engineering and other STEM professions.

Personal vision: enhancing work engagement and the retention of women in the engineering profession

Science.gov (United States)

Buse, Kathleen R.; Bilimoria, Diana

2014-01-01

This study examines how personal vision enhances work engagement and the retention of women in the engineering profession. Using a mixed method approach to understand the factors related to the retention of women in the engineering profession, we first interviewed women who persisted and women who opted out of the profession (Buse and Bilimoria, 2014). In these rich stories, we found that women who persisted had a personal vision that included their profession, and that this personal vision enabled them to overcome the bias, barriers and discrimination in the engineering workplace. To validate this finding on a larger population, we developed a scale to measure one's personal vision conceptualized as the ideal self (Boyatzis and Akrivou, 2006). The measure was tested in a pilot study and then used in a study of 495 women with engineering degrees. The findings validate that the ideal self is comprised of self-efficacy, hope, optimism and core identity. For these women, the ideal self directly impacts work engagement and work engagement directly impacts career commitment to engineering. The findings add to extant theory related to the role of personal vision and intentional change theory. From a practical perspective, these findings will aid efforts to retain women in engineering and other STEM professions. PMID:25538652

Effects of bioethanol ultrasonic generated aerosols application on diesel engine performances

Directory of Open Access Journals (Sweden)

Mariasiu Florin

2015-01-01

Full Text Available In this paper the effects of an experimental bioethanol fumigation application using an experimental ultrasound device on performance and emissions of a single cylinder diesel engine have been experimentally investigated. Engine performance and pollutant emissions variations were considered for three different types of fuels (biodiesel, biodiesel-bioethanol blend and biodiesel and fumigated bioethanol. Reductions in brake specific fuel consumption and NOx pollutant emissions are correlated with the use of ultrasonic fumigation of bioethanol fuel, comparative to use of biodiesel-bioethanol blend. Considering the fuel consumption as diesel engine’s main performance parameter, the proposed bioethanol’s fumigation method, offers the possibility to use more efficient renewable biofuels (bioethanol, with immediate effects on environmental protection.

High-Performance Liquid Chromatography in the Undergraduate Chemical Engineering Laboratory

Science.gov (United States)

Frey, Douglas D.; Guo, Hui; Karnik, Nikhila

2013-01-01

This article describes the assembly of a simple, low-cost, high-performance liquid chromatography (HPLC) system and its use in the undergraduate chemical engineering laboratory course to perform simple experiments. By interpreting the results from these experiments students are able to gain significant experience in the general method of…

Enhancing team-sport athlete performance: is altitude training relevant?

Science.gov (United States)

Billaut, François; Gore, Christopher J; Aughey, Robert J

2012-09-01

Field-based team sport matches are composed of short, high-intensity efforts, interspersed with intervals of rest or submaximal exercise, repeated over a period of 60-120 minutes. Matches may also be played at moderate altitude where the lower oxygen partial pressure exerts a detrimental effect on performance. To enhance run-based performance, team-sport athletes use varied training strategies focusing on different aspects of team-sport physiology, including aerobic, sprint, repeated-sprint and resistance training. Interestingly, 'altitude' training (i.e. living and/or training in O(2)-reduced environments) has only been empirically employed by athletes and coaches to improve the basic characteristics of speed and endurance necessary to excel in team sports. Hypoxia, as an additional stimulus to training, is typically used by endurance athletes to enhance performance at sea level and to prepare for competition at altitude. Several approaches have evolved in the last few decades, which are known to enhance aerobic power and, thus, endurance performance. Altitude training can also promote an increased anaerobic fitness, and may enhance sprint capacity. Therefore, altitude training may confer potentially-beneficial adaptations to team-sport athletes, which have been overlooked in contemporary sport physiology research. Here, we review the current knowledge on the established benefits of altitude training on physiological systems relevant to team-sport performance, and conclude that current evidence supports implementation of altitude training modalities to enhance match physical performances at both sea level and altitude. We hope that this will guide the practice of many athletes and stimulate future research to better refine training programmes.

A new and efficient mechanism for spark ignition engines

International Nuclear Information System (INIS)

Shadloo, M.S.; Poultangari, R.; Abdollahzadeh Jamalabadi, M.Y.; Rashidi, M.M.

2015-01-01

Highlights: • A new slider–crank mechanism, with superior performance is presented. • Thermodynamic processes as well as vibration and internal forces have been modeled. • Comparison with the conventional four-stroke spark ignition engines is made. • Advantages and disadvantages of the proposed mechanism are discussed. - Abstract: In this paper a new symmetrical crank and slider mechanism is proposed and a zero dimensional model is utilized to study its combustion performance enhancement in a four-stroke spark ignition (SI) engine. The main features of this new mechanism are superior thermodynamic efficiency, lower internal frictions, and lower pollutants. Comparison is made between its performance and that of the conventional four-stroke SI engines. Presented mechanism is designed to provide better fuel consumption of internal combustion engines. These advantages over standard engine are achieved through synthesis of new mechanism. Numerical calculation have been performed for several cases of different mechanism parameters, compression ratio and engine speed. A comprehensive comparison between their thermodynamic processes as well as vibration and internal forces has been done. Calculated efficiency and power diagrams are plotted and compared with performance of a conventional SI engine. Advantages and disadvantages of the proposed mechanism are discussed in details

Evaluating the effect of methanol-unleaded gasoline blends on SI engine performance

Directory of Open Access Journals (Sweden)

B Sabahi

2015-09-01

Full Text Available Introduction: Today, all kinds of vehicle engines work with fossil fuels. The limited fossil fuel resources and the negative effects of their consumption on the environment have led researchers to focus on clean, renewable and sustainable energy systems. In all of the fuels being considered as an alternativefor gasoline, methanol is one of the more promising ones and it has experienced major research and development. Methanol can be obtained from many sources, both fossil and renewable; these include coal, natural gas, food industry and municipal waste, wood and agricultural waste. In this study, the effect of using methanol–unleaded gasoline blends on engine performance characteristics has been experimentally investigated. The main objective of the study was to determine engine performance parameters using unleaded gasoline and methanol-unleaded gasoline blends at various engine speeds and loads, and finally achieving an optimal blend of unleaded gasoline and methanol. Materials and Methods: The experimental apparatus consists of an engine test bed with a hydraulic dynamometer which is coupled with a four cylinder, four-stroke, spark ignition engine that is equipped with the carbureted fuel system. The engine has a cylinder bore of 81.5 mm, a stroke of 82.5 mm, and a compression ratio of 7.5:1 with maximum power output of 41.8 kW. The engine speed was monitored continuously by a tachometer, and the engine torque was measured with a hydraulic dynamometer. Fuel consumption was measured by using a calibrated burette (50cc and a stopwatch with an accuracy of 0.01s. In all tests, the cooling water temperature was kept at 82±3˚C. The test room temperature was kept at 29±3˚C during performing the tests. The experiments were performed with three replications. The factors in the experiments were four methanol- unleaded gasoline blends (M0, M10, M20 and M30 and six engine speeds (2000, 2500. 3000, 3500, 4000 and 4500 rpm. Methanol with a purity of

Vehicle driving cycle performance of the spark-less di-ji hydrogen engine

Energy Technology Data Exchange (ETDEWEB)

Boretti, Alberto A. [School of Science and Engineering, University of Ballarat, PO Box663, Ballarat, VIC 3353 (Australia)

2010-05-15

The paper describes coupled CFD combustion simulations and CAE engine performance computations to describe the operation over the full range of load and speed of an always lean burn, Direct Injection Jet Ignition (DI-JI) hydrogen engine. Jet ignition pre-chambers and direct injection are enablers of high efficiencies and load control by quantity of fuel injected. Towards the end of the compression stroke, a small quantity of hydrogen is injected within the spark-less pre-chamber of the DI-JI engine, where it mixes with the air entering from the main chamber and auto-ignites because of the high temperature of the hot glow plug. Then, jets of partially combusted hot gases enter the main chamber igniting there in the bulk, over multiple ignition points, lean stratified mixtures of air and fuel. Engine maps of brake specific fuel consumption vs. speed and brake mean effective pressure are computed first. CAE vehicle simulations are finally performed evaluating the fuel consumption over emission cycles of a vehicle equipped with this engine. (author)

Experimental investigation on performance and exhaust emissions of castor oil biodiesel from a diesel engine.

Science.gov (United States)

Shojaeefard, M H; Etgahni, M M; Meisami, F; Barari, A

2013-01-01

Biodiesel, produced from plant and animal oils, is an important alternative to fossil fuels because, apart from dwindling supply, the latter are a major source of air pollution. In this investigation, effects of castor oil biodiesel blends have been examined on diesel engine performance and emissions. After producing castor methyl ester by the transesterification method and measuring its characteristics, the experiments were performed on a four cylinder, turbocharged, direct injection, diesel engine. Engine performance (power, torque, brake specific fuel consumption and thermal efficiency) and exhaust emissions were analysed at various engine speeds. All the tests were done under 75% full load. Furthermore, the volumetric blending ratios of biodiesel with conventional diesel fuel were set at 5, 10, 15, 20 and 30%. The results indicate that lower blends of biodiesel provide acceptable engine performance and even improve it. Meanwhile, exhaust emissions are much decreased. Finally, a 15% blend of castor oil-biodiesel was picked as the optimized blend of biodiesel-diesel. It was found that lower blends of castor biodiesel are an acceptable fuel alternative for the engine.

Effect of intake swirl on the performance of single cylinder direct injection diesel engine

Science.gov (United States)

Sharma, Vinod Kumar; Mohan, Man; Mouli, Chandra

2017-11-01

In the present work, the effect of inlet manifold geometry and swirl intensity on the direct injection (DI) diesel engine performance was investigated experimentally. Modifications in inlet manifold geometry have been suggested to achieve optimized swirl for the better mixing of fuel with air. The intake swirl intensities of modified cylinder head were measured in swirl test rig at different valve lifts. Later, the overall performance of 435 CC DI diesel engine was measured using modified cylinder head. In addition, the performance of engine was compared for both modified and old cylinder head. For same operating conditions, the brake power and brake specific fuel consumption was improved by 6% and 7% respectively with modified cylinder head compared to old cylinder head. The maximum brake power of 9 HP was achieved for modified cylinder head. The results revealed that the intake swirl has great influence on engine performance.

Optimal Tuner Selection for Kalman Filter-Based Aircraft Engine Performance Estimation

Science.gov (United States)

Simon, Donald L.; Garg, Sanjay

2010-01-01

A linear point design methodology for minimizing the error in on-line Kalman filter-based aircraft engine performance estimation applications is presented. This technique specifically addresses the underdetermined estimation problem, where there are more unknown parameters than available sensor measurements. A systematic approach is applied to produce a model tuning parameter vector of appropriate dimension to enable estimation by a Kalman filter, while minimizing the estimation error in the parameters of interest. Tuning parameter selection is performed using a multi-variable iterative search routine which seeks to minimize the theoretical mean-squared estimation error. This paper derives theoretical Kalman filter estimation error bias and variance values at steady-state operating conditions, and presents the tuner selection routine applied to minimize these values. Results from the application of the technique to an aircraft engine simulation are presented and compared to the conventional approach of tuner selection. Experimental simulation results are found to be in agreement with theoretical predictions. The new methodology is shown to yield a significant improvement in on-line engine performance estimation accuracy

Enhancing Organizational Performance: A Toolbox for Self ...

International Development Research Centre (IDRC) Digital Library (Canada)

Do you know if your organization is performing efficiently? If it isn't, do you know why? This guidebook presents an innovative and thoroughly tested model for organizational self-assessment. The tools and tips in Enhancing Organizational Performance go beyond measuring the impact of programs, products, and services.

Spanish language generation engine to enhance the syntactic quality of AAC systems

Science.gov (United States)

Narváez A., Cristian; Sastoque H., Sebastián.; Iregui G., Marcela

2015-12-01

People with Complex Communication Needs (CCN) face difficulties to communicate their ideas, feelings and needs. Augmentative and Alternative Communication (AAC) approaches aim to provide support to enhance socialization of these individuals. However, there are many limitations in current applications related with systems operation, target scenarios and language consistency. This work presents an AAC approach to enhance produced messages by applying elements of Natural Language Generation. Specifically, a Spanish language engine, composed of a grammar ontology and a set of linguistic rules, is proposed to improve the naturalness in the communication process, when persons with CCN tell stories about their daily activities to non-disabled receivers. The assessment of the proposed method confirms the validity of the model to improve messages quality.

Engineering Strategies to Decode and Enhance the Genomes of Coral Symbionts

KAUST Repository

Levin, Rachel A.; Voolstra, Christian R.; Agrawal, Shobhit; Steinberg, Peter D.; Suggett, David J.; van Oppen, Madeleine J. H.

2017-01-01

Elevated sea surface temperatures from a severe and prolonged El Niño event (2014–2016) fueled by climate change have resulted in mass coral bleaching (loss of dinoflagellate photosymbionts, Symbiodinium spp., from coral tissues) and subsequent coral mortality, devastating reefs worldwide. Genetic variation within and between Symbiodinium species strongly influences the bleaching tolerance of corals, thus recent papers have called for genetic engineering of Symbiodinium to elucidate the genetic basis of bleaching-relevant Symbiodinium traits. However, while Symbiodinium has been intensively studied for over 50 years, genetic transformation of Symbiodinium has seen little success likely due to the large evolutionary divergence between Symbiodinium and other model eukaryotes rendering standard transformation systems incompatible. Here, we integrate the growing wealth of Symbiodinium next-generation sequencing data to design tailored genetic engineering strategies. Specifically, we develop a testable expression construct model that incorporates endogenous Symbiodinium promoters, terminators, and genes of interest, as well as an internal ribosomal entry site from a Symbiodinium virus. Furthermore, we assess the potential for CRISPR/Cas9 genome editing through new analyses of the three currently available Symbiodinium genomes. Finally, we discuss how genetic engineering could be applied to enhance the stress tolerance of Symbiodinium, and in turn, coral reefs.

Carbon storage in the Mississippi River delta enhanced by environmental engineering

Science.gov (United States)

Shields, Michael R.; Bianchi, Thomas S.; Mohrig, David; Hutchings, Jack A.; Kenney, William F.; Kolker, Alexander S.; Curtis, Jason H.

2017-11-01

River deltas have contributed to atmospheric carbon regulation throughout Earth history, but functioning in the modern era has been impaired by reduced sediment loads, altered hydrologic regimes, increased global sea-level rise and accelerated subsidence. Delta restoration involves environmental engineering via river diversions, which utilize self-organizing processes to create prograding deltas. Here we analyse sediment cores from Wax Lake delta, a product of environmental engineering, to quantify the burial of organic carbon. We find that, despite relatively low concentrations of organic carbon measured in the cores (about 0.4%), the accumulation of about 3 T m-2 of sediment over the approximate 60 years of delta building resulted in the burial of a significant amount of organic carbon (16 kg m-2). This equates to an apparent organic carbon accumulation rate of 250 +/- 23 g m-2 yr-1, which implicitly includes losses by carbon emissions and erosion. Our estimated accumulation rate for Wax Lake delta is substantially greater than previous estimates based on the top metre of delta sediments and comparable to those of coastal mangrove and marsh habitats. The sedimentation of carbon at the Wax Lake delta demonstrates the capacity of engineered river diversions to enhance both coastal accretion and carbon burial.

Engineering Strategies to Decode and Enhance the Genomes of Coral Symbionts

KAUST Repository

Levin, Rachel A.

2017-06-30

Elevated sea surface temperatures from a severe and prolonged El Niño event (2014–2016) fueled by climate change have resulted in mass coral bleaching (loss of dinoflagellate photosymbionts, Symbiodinium spp., from coral tissues) and subsequent coral mortality, devastating reefs worldwide. Genetic variation within and between Symbiodinium species strongly influences the bleaching tolerance of corals, thus recent papers have called for genetic engineering of Symbiodinium to elucidate the genetic basis of bleaching-relevant Symbiodinium traits. However, while Symbiodinium has been intensively studied for over 50 years, genetic transformation of Symbiodinium has seen little success likely due to the large evolutionary divergence between Symbiodinium and other model eukaryotes rendering standard transformation systems incompatible. Here, we integrate the growing wealth of Symbiodinium next-generation sequencing data to design tailored genetic engineering strategies. Specifically, we develop a testable expression construct model that incorporates endogenous Symbiodinium promoters, terminators, and genes of interest, as well as an internal ribosomal entry site from a Symbiodinium virus. Furthermore, we assess the potential for CRISPR/Cas9 genome editing through new analyses of the three currently available Symbiodinium genomes. Finally, we discuss how genetic engineering could be applied to enhance the stress tolerance of Symbiodinium, and in turn, coral reefs.

Engineering Strategies to Decode and Enhance the Genomes of Coral Symbionts

Directory of Open Access Journals (Sweden)

Rachel A. Levin

2017-06-01

Full Text Available Elevated sea surface temperatures from a severe and prolonged El Niño event (2014–2016 fueled by climate change have resulted in mass coral bleaching (loss of dinoflagellate photosymbionts, Symbiodinium spp., from coral tissues and subsequent coral mortality, devastating reefs worldwide. Genetic variation within and between Symbiodinium species strongly influences the bleaching tolerance of corals, thus recent papers have called for genetic engineering of Symbiodinium to elucidate the genetic basis of bleaching-relevant Symbiodinium traits. However, while Symbiodinium has been intensively studied for over 50 years, genetic transformation of Symbiodinium has seen little success likely due to the large evolutionary divergence between Symbiodinium and other model eukaryotes rendering standard transformation systems incompatible. Here, we integrate the growing wealth of Symbiodinium next-generation sequencing data to design tailored genetic engineering strategies. Specifically, we develop a testable expression construct model that incorporates endogenous Symbiodinium promoters, terminators, and genes of interest, as well as an internal ribosomal entry site from a Symbiodinium virus. Furthermore, we assess the potential for CRISPR/Cas9 genome editing through new analyses of the three currently available Symbiodinium genomes. Finally, we discuss how genetic engineering could be applied to enhance the stress tolerance of Symbiodinium, and in turn, coral reefs.

Engineering Strategies to Decode and Enhance the Genomes of Coral Symbionts.

Science.gov (United States)

Levin, Rachel A; Voolstra, Christian R; Agrawal, Shobhit; Steinberg, Peter D; Suggett, David J; van Oppen, Madeleine J H

2017-01-01

Elevated sea surface temperatures from a severe and prolonged El Niño event (2014-2016) fueled by climate change have resulted in mass coral bleaching (loss of dinoflagellate photosymbionts, Symbiodinium spp., from coral tissues) and subsequent coral mortality, devastating reefs worldwide. Genetic variation within and between Symbiodinium species strongly influences the bleaching tolerance of corals, thus recent papers have called for genetic engineering of Symbiodinium to elucidate the genetic basis of bleaching-relevant Symbiodinium traits. However, while Symbiodinium has been intensively studied for over 50 years, genetic transformation of Symbiodinium has seen little success likely due to the large evolutionary divergence between Symbiodinium and other model eukaryotes rendering standard transformation systems incompatible. Here, we integrate the growing wealth of Symbiodinium next-generation sequencing data to design tailored genetic engineering strategies. Specifically, we develop a testable expression construct model that incorporates endogenous Symbiodinium promoters, terminators, and genes of interest, as well as an internal ribosomal entry site from a Symbiodinium virus. Furthermore, we assess the potential for CRISPR/Cas9 genome editing through new analyses of the three currently available Symbiodinium genomes. Finally, we discuss how genetic engineering could be applied to enhance the stress tolerance of Symbiodinium , and in turn, coral reefs.

High Temperature Smart Structures for Engine Noise Reduction and Performance Enhancement, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Noise mitigation for subsonic transports is a continuing high priority, and recent work has identified successful exhaust mixing enhancement devices (chevrons) that...

High Temperature Smart Structures for Engine Noise Reduction and Performance Enhancement, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Noise mitigation for subsonic transports is a continuing high priority, and recent work has identified successful exhaust mixing enhancement devices that have...

Evaluation of the performance of a dual fuel engine

Energy Technology Data Exchange (ETDEWEB)

Sato, Toshiharu [The Japan Gas Association, Tokyo (Japan). NGV Project Dept.; Daisho, Yasuhiro; Saito, Takeshi [Waseda Univ., Tokyo (Japan)

1998-12-31

Dual fuel operation, in which natural gas is mixed with the diesel engine intake air and ignition is by diesel fuel spray, has the advantage that engine conversion is simple. Under high load it has the same high efficiency as a diesel engine and it can be switched to normal diesel operation for long distance running. Also, NO{sub x} and black smoke emissions can also be reduced. However, the disadvantages are to increase HC and CO emissions, to reduce efficiency under low load, and to emit the large amount of NO{sub x} under high load. Waseda University was commissioned by Tokyo Gas Co., Ltd. to conduct research program involving experimentation ragarding a dual fuel engine. It was then discovered that the most effective means of solving the problems mentioned above is Exhaust Gas Recirculation (EGR) and that the effect can be increased by heating the intake air. An old engine before the current emission standard was converted to dual fuel operation. It was found that these measures enables NO{sub x}, black smoke and CO{sub 2} to be reduced while high thermal efficiency was maintained. They did not reach the point of satisfying latest Japanese emission standard. But it seemed that good results would have been obtained, if a base engine with good emissions had been converted for dual fuel operation. The results of assessing the performance of the dual fuel engine at this time are reported here, centered on the effect of EGR and intake heating. (orig.)

The Effect of Ethanol-Diesel Blends on The Performance of A Direct Injection Diesel Engine

OpenAIRE

Arifin Nur; Yanuandri Putrasari; Iman Kartolaksono Reksowardojo

2012-01-01

The experiment was conducted on a conventional direct injection diesel engine. Performance test was carried out to evaluate the performance and emission characteristics of a conventional diesel engine that operates on ethanol-diesel blends. The test procedure was performed by coupling the diesel engine on the eddy current dynamometer. Fuel consumption was measured using the AVL Fuel Balance, and a hotwire anemometer was used to measure the air consumption. Some of the emission test devices we...

Improving the performance of a compression ignition engine by directing flow of inlet air

Science.gov (United States)

Kemper, Carlton

1946-01-01

The object of this report is to present the results of tests performed by the National Advisory Committee for Aeronautics to determine the effect on engine performance of directing the flow of the inlet air to a 5-inch by 7-inch cylinder, solid injection, compression ignition engine, After a few preliminary tests, comparative runs were made at a speed of 1500 r.p.m. with and without directed air flow. It was found that directing the flow of the inlet air toward the fuel injection valve gave steadier engine operation, and an appreciable increase in power, and decreased fuel consumption. The results indicate the possibility of improving the performance of a given type of combustion chamber without changing its shape and with no change in valve timing. They would also seem to prove that directional turbulence, set up before the inlet valve of a four-stroke cycle engine, continues in the engine cylinder throughout the compression stroke.

Engineering of complex systems: The impact of systems engineering at NASA

Science.gov (United States)

Kludze, Ave-Klutse Kodzo Paaku

The "true" impact or value of systems engineering to an organization unfortunately appears not to have been well-studied and understood. The principles of systems engineering are highly encouraged by NASA at all levels, and most practitioners, both internal and external to NASA, intuitively "believe" it adds some value to the development of complex systems by producing them faster, better and cheaper. This research, in trying to fill a gap that exists in the systems engineering literature, analyzes data collected within NASA and other sources external to NASA (INCOSE) for comparisons. Analyses involving a number of case studies performed on selected NASA projects are presented to draw attention to the impact systems engineering had or could have had on these projects. This research clearly shows that systems engineering does add value to projects within and outside NASA. The research results further demonstrate that systems engineering has been beneficial not only to NASA but also to organizations within which INCOSE members work. It was determined, however, that systems engineering does not operate in a vacuum and may not always guarantee success through mere application. During this research, it was discovered that the lack of or inadequate application of systems engineering in the development of complex systems may result in cost overruns, poor technical performance, project delays, and in some cases unmitigated risk with disastrous consequences including the loss of life and property. How much is saved (in terms of cost, schedule) or improved (in terms of technical performance) as a result of its implementation may never be known precisely, but by indirectly measuring its value or impact on a project, percentages of project budget spent on systems engineering activities and any schedule reductions or performance enhancements realized could be determined. According to this research, systems engineering is not a waste of time and resources; in most cases, it is

A study experiment of auto idle application in the excavator engine performance

Energy Technology Data Exchange (ETDEWEB)

Purwanto, Wawan, E-mail: wawan5527@gmail.com; Maksum, Hasan; Putra, Dwi Sudarno, E-mail: dwisudarnoputra@ft.unp.ac.id; Wahyudi, Retno [State University of Padang, West Sumatera (Indonesia); Azmi, Meri, E-mail: meriazmi@gmail.com [State Polytechnic of Padang, West Sumatera (Indonesia)

2016-03-29

The purpose of this study was to analyze the effect of applying auto idle to excavator engine performance, such as machine unitization and fuel consumption in Excavator. Steps to be done are to modify the system JA 44 and 67 in Vehicle Electronic Control Unit (V-ECU). The modifications will be obtained from the pattern of the engine speed. If the excavator attachment is not operated, the engine speed will return to the idle speed automatically. From the experiment results the auto idle reduces fuel consumption in excavator engine.

Performance evaluation and experiment system for waste heat recovery of diesel engine

International Nuclear Information System (INIS)

Wenzhi, Gao; Junmeng, Zhai; Guanghua, Li; Qiang, Bian; Liming, Feng

2013-01-01

In this paper, a waste heat recovery system is proposed where a high speed turbocharged diesel engine acts as the topper of a combined cycle with exhaust gases used for a bottoming Rankine cycle. The paper describes a mathematical model to evaluate the performance of Rankine cycle system with a reciprocating piston expander. The paper focuses on the performance evaluation and parameter selection of the heat exchanger and reciprocating piston expander that are suitable to waste heat recovery of ICE (internal combustion engine). The paper also describes the experimental setup and the preliminary results. The simulation results show that a proper intake pressure should be 4–5 MPa at its given mass flow rate of 0.015–0.021 kg/s depending on the waste heat recovery of a turbocharged diesel engine (80 kW/2590 rpm). The net power and net power rise rate at various ICE rotation speeds are calculated. The result shows that introducing heat recovery system can increase the engine power output by 12%, when diesel engine operates at 80 kW/2590 rpm. The preliminary experimental results indirectly prove the simulation model by two negative work loops in the P–V curve, under a low intake pressure and steam flow rate condition. - Highlights: • We investigate waste heat recovery through secondary fluid power cycle. • We establish a thermodynamic model of reciprocating steam engine. • We conduct the performance evaluation and experimental system development. • Primary parameters of the heat exchangers and expander are determined

Enhanced thermophysical properties via PAO superstructure

Science.gov (United States)

Pournorouz, Zahra; Mostafavi, Amirhossein; Pinto, Aditya; Bokka, Apparao; Jeon, Junha; Shin, Donghyun

2017-01-01

For the last few years, molten salt nanomaterials have attracted many scientists for their enhanced specific heat by doping a minute concentration of nanoparticles (up to 1% by weight). Likewise, enhancing the specific heat of liquid media is important in many aspects of engineering such as engine oil, coolant, and lubricant. However, such enhancement in specific heat was only observed for molten salts, yet other engineering fluids such as water, ethylene glycol, and oil have shown a decrease of specific heat with doped nanoparticles. Recent studies have shown that the observed specific heat enhancement resulted from unique nanostructures that were formed by molten salt molecules when interacting with nanoparticles. Thus, such enhancement in specific heat is only possible for molten salts because other fluids may not naturally form such nanostructures. In this study, we hypothesized such nanostructures can be mimicked through in situ formation of fabricated nano-additives, which are putative nanoparticles coated with useful organic materials (e.g., polar-group-ended organic molecules) leading to superstructures, and thus can be directly used for other engineering fluids. We first applied this approach to polyalphaolefin (PAO). A differential scanning calorimeter (DSC), a rheometer, and a customized setup were employed to characterize the heat capacity, viscosity, and thermal conductivity of PAO and PAO with fabricated nano-additives. Results showed 44.5% enhanced heat capacity and 19.8 and 22.98% enhancement for thermal conductivity and viscosity, respectively, by an addition of only 2% of fabricated nanostructures in comparison with pure PAO. Moreover, a partial melting of the polar-group-ended organic molecules was observed in the first thermal cycle and the peak disappeared in the following cycles. This indicates that the in situ formation of fabricated nano-additives spontaneously occurs in the thermal cycle to form nanostructures. Figure of merit analyses have

Enhanced thermophysical properties via PAO superstructure.

Science.gov (United States)

Pournorouz, Zahra; Mostafavi, Amirhossein; Pinto, Aditya; Bokka, Apparao; Jeon, Junha; Shin, Donghyun

2017-12-01

For the last few years, molten salt nanomaterials have attracted many scientists for their enhanced specific heat by doping a minute concentration of nanoparticles (up to 1% by weight). Likewise, enhancing the specific heat of liquid media is important in many aspects of engineering such as engine oil, coolant, and lubricant. However, such enhancement in specific heat was only observed for molten salts, yet other engineering fluids such as water, ethylene glycol, and oil have shown a decrease of specific heat with doped nanoparticles. Recent studies have shown that the observed specific heat enhancement resulted from unique nanostructures that were formed by molten salt molecules when interacting with nanoparticles. Thus, such enhancement in specific heat is only possible for molten salts because other fluids may not naturally form such nanostructures. In this study, we hypothesized such nanostructures can be mimicked through in situ formation of fabricated nano-additives, which are putative nanoparticles coated with useful organic materials (e.g., polar-group-ended organic molecules) leading to superstructures, and thus can be directly used for other engineering fluids. We first applied this approach to polyalphaolefin (PAO). A differential scanning calorimeter (DSC), a rheometer, and a customized setup were employed to characterize the heat capacity, viscosity, and thermal conductivity of PAO and PAO with fabricated nano-additives. Results showed 44.5% enhanced heat capacity and 19.8 and 22.98% enhancement for thermal conductivity and viscosity, respectively, by an addition of only 2% of fabricated nanostructures in comparison with pure PAO. Moreover, a partial melting of the polar-group-ended organic molecules was observed in the first thermal cycle and the peak disappeared in the following cycles. This indicates that the in situ formation of fabricated nano-additives spontaneously occurs in the thermal cycle to form nanostructures. Figure of merit analyses have

Effect of hydroxy (HHO) gas addition on gasoline engine performance and emiss

OpenAIRE

Mohamed M. EL-Kassaby; Yehia A. Eldrainy; Mohamed E. Khidr; Kareem I. Khidr

2016-01-01

The objective of this work was to construct a simple innovative HHO generation system and evaluate the effect of hydroxyl gas HHO addition, as an engine performance improver, into gasoline fuel on engine performance and emissions. HHO cell was designed, fabricated and optimized for maximum HHO gas productivity per input power. The optimized parameters were the number of neutral plates, distance between them and type and quantity of two catalysts of Potassium Hydroxide (KOH) and sodium hydroxi...

Effect of hydroxy (HHO gas addition on gasoline engine performance and emiss

Directory of Open Access Journals (Sweden)

Mohamed M. EL-Kassaby

2016-03-01

Full Text Available The objective of this work was to construct a simple innovative HHO generation system and evaluate the effect of hydroxyl gas HHO addition, as an engine performance improver, into gasoline fuel on engine performance and emissions. HHO cell was designed, fabricated and optimized for maximum HHO gas productivity per input power. The optimized parameters were the number of neutral plates, distance between them and type and quantity of two catalysts of Potassium Hydroxide (KOH and sodium hydroxide (NaOH. The performance of a Skoda Felicia 1.3 GLXi gasoline engine was evaluated with and without the optimized HHO cell. In addition, the CO, HC and NOx emissions were measured using TECNO TEST exhaust gas analyzer TE488. The results showed that the HHO gas maximum productivity of the cell was 18 L/h when using 2 neutrals plates with 1 mm distance and 6 g/L of KOH. The results also showed 10% increment in the gasoline engine thermal efficiency, 34% reduction in fuel consumption, 18% reduction in CO, 14% reduction in HC and 15% reduction in NOx.

Exploring Advanced Technology Gas Turbine Engine Design and Performance for the Large Civil Tiltrotor (LCTR)

Science.gov (United States)

Snyder, Christopher A.

2014-01-01

A Large Civil Tiltrotor (LCTR) conceptual design was developed as part of the NASA Heavy Lift Rotorcraft Systems Investigation in order to establish a consistent basis for evaluating the benefits of advanced technology for large tiltrotors. The concept has since evolved into the second-generation LCTR2, designed to carry 90 passengers for 1,000 nautical miles at 300 knots, with vertical takeoff and landing capability. This paper explores gas turbine component performance and cycle parameters to quantify performance gains possible for additional improvements in component and material performance beyond those identified in previous LCTR2 propulsion studies and to identify additional research areas. The vehicle-level characteristics from this advanced technology generation 2 propulsion architecture will help set performance levels as additional propulsion and power systems are conceived to meet ever-increasing requirements for mobility and comfort, while reducing energy use, cost, noise and emissions. The Large Civil Tiltrotor vehicle and mission will be discussed as a starting point for this effort. A few, relevant engine and component technology studies, including previous LCTR2 engine study results will be summarized to help orient the reader on gas turbine engine architecture, performance and limitations. Study assumptions and methodology used to explore engine design and performance, as well as assess vehicle sizing and mission performance will then be discussed. Individual performance for present and advanced engines, as well as engine performance effects on overall vehicle size and mission fuel usage, will be given. All results will be summarized to facilitate understanding the importance and interaction of various component and system performance on overall vehicle characteristics.

Effect of water-containing acetone–butanol–ethanol gasoline blends on combustion, performance, and emissions characteristics of a spark-ignition engine

International Nuclear Information System (INIS)

Li, Yuqiang; Nithyanandan, Karthik; Lee, Timothy H.; Donahue, Robert Michael; Lin, Yilu; Lee, Chia-Fon; Liao, Shengming

2016-01-01

Highlights: • Water-containing ABE (acetone–butanol–ethanol) was used an alternative fuel. • Water-containing ABE and gasoline blends were investigated in an SI engine. • Water-containing ABE and gasoline blends can enhance engine torque. • Water-containing ABE and gasoline blends can reduce CO, UHC and NO_x emissions. - Abstract: Bio-butanol has proved to be a promising alternative fuel in recent years; it is typically produced from ABE (acetone–butanol–ethanol) fermentation from non-edible biomass feedstock. The high costs for dehydration and recovery from dilute fermentation broth have so far prohibited bio-butanol’s use in internal combustion engines. There is an interesting in studying the intermediate fermentation product, i.e. water-containing ABE as a potential fuel. However, most previous studies covered the use of water-containing ABE–diesel blends. In addition, previous studies on SI engines fueled with ABE did not consider the effect of water. Therefore, the evaluation of water-containing ABE gasoline blends in a port fuel-injected spark-ignition (SI) engine was carried out in this study. Effect of adding ABE and water into gasoline on combustion, performance and emissions characteristics was investigated by testing gasoline, ABE30, ABE85, ABE29.5W0.5 and ABE29W1 (29 vol.% ABE, 1 vol.% water and 70 vol.% gasoline). In addition, ABE29W1 was compared with gasoline under various equivalence ratios (Φ = 0.83–1.25) and engine loads (3 and 5 bar BMEP). It was found that ABE29W1 generally had higher engine toque (3.1–8.2%) and lower CO (9.8–35.1%), UHC (27.4–78.2%) and NO_x (4.1–39.4%) than those of gasoline. The study indicated that water-containing ABE could be used in SI engines as an alternative fuel with good engine performance and low emissions.

Design and manufacture of high performance hollow engine valves by Additive Layer Manufacturing

International Nuclear Information System (INIS)

Cooper, D.; Thornby, J.; Blundell, N.; Henrys, R.; Williams, M.A.; Gibbons, G.

2015-01-01

Highlights: • High performance engine valve has been redesigned and optimised for and using ALM. • FEA was utilised to optimise and select a design for manufacture and testing. • Micro computed tomography was used in design and validation as an NDT technique. • Real world test of components was conducted to evaluate their performance. • Has demonstrated the potential for ALM in a high performance engineering context. - Abstract: Additive Layer Manufacture (ALM) of metallic components provides significant opportunities for the reduction of component weight, in order to realise improvements in vehicle fuel efficiency or performance. This paper examines the potential benefits of ALM with regard to reducing the weight of Internal Combustion Engine inlet or exhaust valves. A case study component is presented, for which an improved ALM design has been created, manufactured and evaluated. Micro-Computed Tomography (μ-CT) scanning was utilised to reverse engineer an original component, and to assess the ALM component’s internal geometry and material integrity. The case study valve was re-designed using Finite Element Analysis (FEA) to select a light weighted design which provides a conservative 9.4 g, (20%) weight saving on the Original Equipment Manufacturer (OEM) component. An engine test of over 175,000 cycles at between 2000 and 9500 rpm was conducted, after which μ-CT scanning confirmed no evidence of internal cracking, failure or significant deformation

Performance Assessment and Scooter Verification of Nano-Alumina Engine Oil

Directory of Open Access Journals (Sweden)

Yu-Feng Lue

2016-09-01

Full Text Available The performance assessment and vehicle verification of nano-alumina (Al2O3 engine oil (NAEO were conducted in this study. The NAEO was produced by mixing Al2O3 nanoparticles with engine oil using a two-step synthesis method. The weight fractions of the Al2O3 nanoparticles in the four test samples were 0 (base oil, 0.5, 1.5, and 2.5 wt. %. The measurement of basic properties included: (1 density; (2 viscosity at various sample temperatures (20–80 °C. A rotary tribology testing machine with a pin-on-disk apparatus was used for the wear test. The measurement of the before-and-after difference of specimen (disk weight (wear test indicates that the NAEO with 1.5 wt. % Al2O3 nanoparticles (1.5 wt. % NAEO was the chosen candidate for further study. For the scooter verification on an auto-pilot dynamometer, there were three tests, including: (1 the European Driving Cycle (ECE40 driving cycle; (2 constant speed (50 km/h; and (3 constant throttle positions (20%, 40%, 60%, and 90%. For the ECE40 driving cycle and the constant speed tests, the fuel consumption was decreased on average by 2.75%, while it was decreased by 3.57% for the constant throttle case. The experimental results prove that the engine oil with added Al2O3 nanoparticles significantly decreased the fuel consumption. In the future, experiments with property tests of other nano-engine oils and a performance assessment of the nano-engine-fuel will be conducted.

Experimental investigation on performance characteristics of a diesel engine using diesel-water emulsion with oxygen enriched air

Directory of Open Access Journals (Sweden)

P. Baskar

2017-03-01

Full Text Available Diesel engines occupy a crucial position in automobile industry due to their high thermal efficiency and high power to weight ratio. However, they lag behind in controlling air polluting components coming out of the engine exhaust. Therefore, diesel consumption should be analyzed for future energy consumption and this can be primarily controlled by the petroleum fuel substitution techniques for existing diesel engines, which include biodiesel, alcohol-diesel emulsions and diesel water emulsions. Among them the diesel water emulsion is found to be most suitable fuel due to reduction in particulate matter and NOx emission, besides that it also improves the brake thermal efficiency. But the major problem associated with emulsions is the ignition delay, since this is responsible for the power and torque loss. A reduction in NOx emission was observed due to reduction in combustion chamber temperature as the water concentration increases. However the side effect of emulsified diesel is a reduction in power which can be compensated by oxygen enrichment. The present study investigates the effects of oxygen concentration on the performance characteristics of a diesel engine when the intake air is enriched to 27% of oxygen and fueled by 10% of water diesel emulsion. It was found that the brake thermal efficiency was enhanced, combustion characteristics improved and there is also a reduction in HC emissions.

An extraordinary transmission analogue for enhancing microwave antenna performance

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Sarin V. Pushpakaran

2015-10-01

Full Text Available The theory of diffraction limit proposed by H.A Bethe limits the total power transfer through a subwavelength hole. Researchers all over the world have gone through different techniques for boosting the transmission through subwavelength holes resulting in the Extraordinary Transmission (EOT behavior. We examine computationally and experimentally the concept of EOT nature in the microwave range for enhancing radiation performance of a stacked dipole antenna working in the S band. It is shown that the front to back ratio of the antenna is considerably enhanced without affecting the impedance matching performance of the design. The computational analysis based on Finite Difference Time Domain (FDTD method reveals that the excitation of Fabry-Perot resonant modes on the slots is responsible for performance enhancement.

Engineering Encounters: Reverse Engineering

Science.gov (United States)

McGowan, Veronica Cassone; Ventura, Marcia; Bell, Philip

2017-01-01

This column presents ideas and techniques to enhance your science teaching. This month's issue shares information on how students' everyday experiences can support science learning through engineering design. In this article, the authors outline a reverse-engineering model of instruction and describe one example of how it looked in our fifth-grade…

Multimedia Search Engines : Concept, Performance, and Types

OpenAIRE

Sayed Rabeh Sayed

2005-01-01

A Research about multimedia search engines, it starts with definition of search engines at general and multimedia search engines, then explains how they work, and divided them into: Video search engines, Images search engines, and Audio search engines. Finally, it reviews a samples to multimedia search engines.

An Experimental Investigation of Ethanol-Diesel Blends on Performance and Exhaust Emissions of Diesel Engines

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Tarkan Sandalcı

2014-08-01

Full Text Available Ethanol is a promising alternative fuel, due to its renewable biobased origin. Also, it has lower carbon content than diesel fuel and it is oxygenated. For this reason, ethanol is providing remarkable potential to reduce particulate emulsions in compression-ignition engines. In this study, performance of ethanol-diesel blends has been investigated experimentally. Tested fuels were mineral diesel fuel (E0D100, 15% (v/v ethanol/diesel fuel blend (E15D85, and 30% (v/v ethanol/diesel fuel blend (E30D70. Firstly, the solubility of ethanol and diesel was experienced. Engine tests were carried out to reveal the performance and emissions of the engine fuelled with the blends. Full load operating conditions at various engine speeds were investigated. Engine brake torque, brake power, brake specific fuel consumption, brake thermal efficiency, exhaust gas temperature, and finally exhaust emissions were measured. Performance of the tested engine decreased substantially while improvement on smoke and gaseous emissions makes ethanol blend favorable.

Performance Characteristics Comparison of CNG Port and CNG Direct Injection in Spark Ignition Engine

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Rajesh Patel

2018-03-01

Full Text Available A comparative performance analysis is being carried out on a four cylinder, four stroke cycle, spark ignition engine having displacement volume 1297cc. The cylinder head of original gasoline based engine was modified by drilling holes from upper surfaces of head to individual combustion chamber to convert the engine in a CNG direct injection engine. The CNG port injection (CNG-PI system and CNG direct injection (CNG-DI system were incorporated with the single engine.  The engine was retrofitted to run on both CNG-PI and CNG-DI system alternately with common CNG tank and other engine loading and measurement system. The engine was equipped with electrical dynamometer having rheostat type loading. The CNG direct injection system was incorporated with various sensors and engine ECU. The operating parameters can be obtained on computer screen by loading the computer with engine through switch box. The engine was run over the speed range of 1000 rpm to 3000 rpm with incremental speed of 300 rpm. The performance parameters were calculated from observations and recorded for both CNG-PI and CNG-DI system. The experimental investigation exhibits that, the average 7-8% reduction in BSFC while the engine was running with CNG-DI system as compared to that of CNG-PI system. Also the engine produced 8-9% higher brake torque and hence higher brake power. The engine gives 6-7% higher brake thermal efficiency with CNG-DI system as compared to CNG-PI system.