Littérature scientifique sur le sujet « Maximal oxigen consumption »

The paper suggests a mechanism of simultaneous oxide reduction from multicomponent copper-smelting slags during their bubbling with CO–CO2 reducing mixtures and provides a numerical algorithm developed to implement this mechanism as a mathematical model. The first feature of the suggested mechanism is a statement that the total speed of the overall reduction process is determined by CO consumption during its interaction with oxygen ions formed in slag oxide dissociation. The second feature is a statement about equilibrium achieved between slag, alloy and gaseous phase according to the system oxidizing potential reached at every instant. The paper demonstrates a satisfactory agreement between calculated and experimental data obtained when reducing industrial coppersmelting slags at 1300 °С and СО/СО2 = 4, 6, 156, and using the first-degree kinetic equation regarding the difference between initial and equilibrium CO contents in the gaseous phase. A generalized kinetic constant of the multicomponent slag reduction reaction rate is calculated as k = 2.6·10–7, moles CO /(cm2 · sec·%) at 1300 °С. It is shown that during industrial multicomponent slag reduction, reduction speed of copper (I) oxide and magnetite are high and close to maximal ones as early as at the first minutes of slag bubbling with reducing gas. At the same time, for Fe(II), lead and zinc oxides they are low at the first minutes of the process, and increase gradually to reach their maximum, and then decrease again up to near-zero values as the supplied gas and melt come to equilibrium. Generally, oxide reduction speed naturally decreases with approaching to equilibrium between the initial gas and liquid phases, and this should be taken into account when designing continuous slag depletion processes.

The 2018 IPCC (The Intergovernmental Panel on Climate Change’s) report defined the goal to limit global warming to 1.5 °C by 2050. This will require “rapid and far-reaching transitions in land, energy, industry, buildings, transport, and cities”. The challenge falls on all sectors, especially energy production and industry. In this regard, the recent progress and future challenges of greenhouse gas emissions and energy supply are first briefly introduced. Then, the current situation of the steel industry is presented. Steel production is predicted to grow by 25–30% by 2050. The dominant iron-making route, blast furnace (BF), especially, is an energy-intensive process based on fossil fuel consumption; the steel sector is thus responsible for about 7% of all anthropogenic CO2 emissions. In order to take up the 2050 challenge, emissions should see significant cuts. Correspondingly, specific emissions (t CO2/t steel) should be radically decreased. Several large research programs in big steelmaking countries and the EU have been carried out over the last 10–15 years or are ongoing. All plausible measures to decrease CO2 emissions were explored here based on the published literature. The essential results are discussed and concluded. The specific emissions of “world steel” are currently at 1.8 t CO2/t steel. Improved energy efficiency by modernizing plants and adopting best available technologies in all process stages could decrease the emissions by 15–20%. Further reductions towards 1.0 t CO2/t steel level are achievable via novel technologies like top gas recycling in BF, oxygen BF, and maximal replacement of coke by biomass. These processes are, however, waiting for substantive industrialization. Generally, substituting hydrogen for carbon in reductants and fuels like natural gas and coke gas can decrease CO2 emissions remarkably. The same holds for direct reduction processes (DR), which have spread recently, exceeding 100 Mt annual capacity. More radical cut is possible via CO2 capture and storage (CCS). The technology is well-known in the oil industry; and potential applications in other sectors, including the steel industry, are being explored. While this might be a real solution in propitious circumstances, it is hardly universally applicable in the long run. More auspicious is the concept that aims at utilizing captured carbon in the production of chemicals, food, or fuels e.g., methanol (CCU, CCUS). The basic idea is smart, but in the early phase of its application, the high energy-consumption and costs are disincentives. The potential of hydrogen as a fuel and reductant is well-known, but it has a supporting role in iron metallurgy. In the current fight against climate warming, H2 has come into the “limelight” as a reductant, fuel, and energy storage. The hydrogen economy concept contains both production, storage, distribution, and uses. In ironmaking, several research programs have been launched for hydrogen production and reduction of iron oxides. Another global trend is the transfer from fossil fuel to electricity. “Green” electricity generation and hydrogen will be firmly linked together. The electrification of steel production is emphasized upon in this paper as the recycled scrap is estimated to grow from the 30% level to 50% by 2050. Finally, in this review, all means to reduce specific CO2 emissions have been summarized. By thorough modernization of production facilities and energy systems and by adopting new pioneering methods, “world steel” could reach the level of 0.4–0.5 t CO2/t steel and thus reduce two-thirds of current annual emissions.

Summary Oils that are potential candidates for in situ combustion recovery processes are often screened by means of their oxidation characteristics: in particular, the kinetics of the ignition process and the transition from low-temperature to high-temperature oxidation through what is known as the "negative temperature gradient region." These characteristics are readily studied in ramped-temperature oxidation tests, which involve the controlled heating of recombined, oil-saturated cores in a one-dimensional plug flow reactor under a flowing stream of air (or oxygen-containing gas). The purpose of these tests is to study the global oxidation behavior and reaction kinetics under controlled conditions, with the end purpose of providing realistic data for incorporation into a numerical simulator which can be used to predict field performance. A ramped-temperature oxidation apparatus was used to conduct a detailed, two-year parametric study of the oxidation characteristics of Athabasca Oil Sands bitumen. The text matrix involved various levels of pressure, gas injection rate, oxygen content of the injected gas, and maximum ramptemperature. This paper details the principal findings for the 45-test study;especially the need to maintain high reaction temperatures >380°C) in order to mobilize and produce heavy oils under conditions of dry in situ combustion. Design considerations and operational guidelines for successful field projectsarising from the results of this study are also discussed. Introduction In order to successfully exploit the vast potential of processes based on the injection of air or an oxygen-containing gas for the recovery of conventional and heavy oils, it is necessary to understand the nature of the oxidation reactions which are involved. The traditional definition of in situ combustion, which is based on the high-temperature combustion of a coke-like fuel, does not explain the combustion behavior which is observed in many field projects or even in laboratory combustion tube experiments. For this reason, a number of experiments have been developed which concentrate on the global oxidation kinetics. These studies normally involve exposing the crude oil to a programmed rate of heating while in contact with the oxidizing gas. The oxidation kinetics are then observed using effluent gas analysis techniques,1–7 and differential thermal techniques such as the differential thermal analysis (DTA) work of Vossoughi et al.,8 the pressurized differential scanning calorimetry (PDSC) studies of Phillips et al.9 and Belkharchouche and Hughes,10 and the accelerating rate calorimetry (ARC) technique of Yannimaras et al.11 Previous investigations of the oxidation reactions which occur during in situ combustion processes have shown the existence of at least two temperature ranges over which the oxygen uptake rates are significant. 2,4-7While Kisler and Shallcross have reported that the light (40.2°API) Australian oil which they studied exhibited at least three temperature ranges over which localized maxima in the oxygen uptake rate were observed, the majority of heavy oils for which oxidation data have been reported show only two distinct local maxima in the oxidation rates. For convenience, the two temperature ranges where elevated oxygen uptake or energy generation rates are observed are denoted as the low-temperature oxidation (LTO) and high-temperature combustion(HTC) regions. For heavy oils, the range of temperatures associated with the low-temperature oxidation region is roughly from 150 to 300°C, while the high-temperature combustion region generally corresponds to reaction temperatures in the range from 380 to 800°C. The transition temperature range which falls between the low-temperature oxidation and high-temperature combustion regions is characterized by reduced oxygen uptake and energy generation rates. The lower temperature portion of this transition range in which the oxygen uptake and energy generation rates decrease with increasing temperature is the "negative temperature gradient region" (NTGR). This behavior is illustrated in Fig. 1, which is the temperature history for a test involving a heater temperature of 350°C (near the upper end of the NTGR). This test, which was previously described by Moore et al.,12 shows that a distinct low-temperature reaction zone formed when the temperature was approximately 140°C and it propagated through the core for a short period of time as the heater continued its ramp towards the setpoint maximum temperature of 350°C At the end of the propagation period, the centerline temperatures remained very close to the heater temperature as the latter was increased over the temperature interval from 280 to 330°C It is apparent from the small temperature differences between all of the centerline locations and the heater that energy generation over this temperature interval was very low. A high-temperature reaction zone started to form when the temperature at the first thermocouple location attained 355°C. Fig. 2 provides the oxygen uptake history for the same test, and the data show that there were also two distinct periods of high oxygen uptake rates. The first period corresponds to the time that the lower-temperature reaction zone propagated through the core, and it is apparent that the prime mode of oxygen uptake is by reactions which do not result in the formation of carbon oxides. These reactions have been denoted as LTO reactions, although it should be noted that hydrogen conversion to water (which is normally classified as a combustion reaction) is included as a LTO reaction. Oxygen uptake rates associated with the second period correspond to the propagation of the high-temperature reaction zone. At these higher temperatures, oxygen consumption is primarily associated with the formation of carbon oxides. Oxygen uptake by LTO reactions is also significant, but this reflects the inclusion of hydrogen conversion to water as a LTO reaction. In essence, the oxidation reactions associated with the high-temperature propagating reaction zone are those which are normally designated as high-temperature combustion, in that the primary products are carbon oxides and water.

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The relation between metabolic demand and maximal oxygen consumption during exercise have been investigated in different areas of knowledge. In the health field, the determination of maximal oxygen consumption (VO2max) is considered a method to classify the level of physical fitness or the risk of cardiocirculatory diseases. The accuracy to obtain data provides a better evaluation of functional responses and allows a reduction in the error margin at the moment of risk classification, as well as, at the moment of determination of aerobic exercise work load. In Brasil, the use of respirometry associated to ergometric test became an opition in the cardiorespiratory evaluation. This equipment allows predictions concerning the oxyredutase process, making it possible to identify physiological responses to physical effort as the respiratory threshold. This thesis focused in the development of mathematical models developed by multiple regression validated by the stepwise method, aiming to predict the VO2max based on respiratory responses to physical effort. The sample was composed of a ramdom sample of 181 healthy individuals, men and women, that were randomized to two groups: regression group and cross validation group (GV). The voluntiars were submitted to a incremental treadmill test; objetiving to determinate of the second respiratory threshold (LVII) and the Peak VO2max. Using the m?todo forward addition method 11 models of VO2max prediction in trendmill were developded. No significative differences were found between the VO2max meansured and the predicted by models when they were compared using ANOVA One-Way and the Post Hoc test of Turkey. We concluded that the developed mathematical models allow a prediction of the VO2max of healthy young individuals based on the LVII
A rela??o entre a demanda metab?lica e o consumo de oxig?nio durante a pr?tica de exerc?cios f?sicos ? alvo de investiga??o em distintas ?reas do conhecimento. No campo da sa?de, a determina??o do consumo m?ximo de oxig?nio (VO2m?x) ? considerada um m?todo para classificar o n?vel de aptid?o f?sica ou risco de doen?as cardiocirculat?rias. A obten??o de dados de forma acurada possibilita uma melhor avalia??o das respostas funcionais, o que permite reduzir a margem de erros tanto no momento da classifica??o dos riscos, como tamb?m no momento da determina??o das cargas de treinamento aer?bico. No Brasil a utiliza??o da ventilometria conjugado ao teste de ergom?trico passou a ser uma op??o na avalia??o cardiorrespirat?ria. O emprego deste equipamento possibilita inferir sobre o processo de oxidorredutase, permitindo identificar respostas fisiol?gicas ao esfor?o como o limiar ventilat?rio. A presente tese centrou-se no desenvolvimento de modelos matem?ticos desenvolvidos por meio de regress?o m?ltipla com valida??o pelo m?todo stepwise com o objetivo de predi??o do VO2m?x tomando como base, as respostas ventilat?rias ao esfor?o. Para tanto, o estudo contou com uma amostra aleat?ria de 181 indiv?duos saud?veis, de ambos os sexos, que foram randomizados em dois grupos: grupo de regress?o e o grupo de valida??o cruzada (GV). Os volunt?rios foram submetidos a teste cardiopulmonar em esteira rolante em protocolo incremental; onde se visou a determina??o do limiar ventilat?rio II (LVII) e o VO2m?x de pico. Atrav?s da aplica??o do m?todo adi??o forward foram desenvolvidos 11 modelos de predi??o do VO2m?x em esteira rolante. N?o foram encontradas diferen?as significativa entre o VO2m?x mensurado com os preditos pelos modelos quando comparados pelo teste t pareado. Os resultados possibilitam-nos concluir que os modelos matem?ticos desenvolvidos permitem estimar o VO2m?x de indiv?duos jovens e h?gidos, tendo como ponto de refer?ncia o LVII

O orientador do trabalho n?o mencionado na lista da folha de aprova??o.
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O Incremental Shuttle Walking Test (ISWT) vem sendo utilizado na avalia??o da aptid?o cardiorrespirat?ria (ACR) de crian?as e adolescentes com diferentes condi??es de sa?de. N?o se sabe se a resposta cardiorrespirat?ria apresentada por adolescentes saud?veis no ISWT ir? se assemelhar aquela induzida pelo teste de esfor?o cardiopulmonar (TECP). Os objetivos deste estudo foram: (1) Avaliar se o ISWT ? um teste m?ximo para adolescentes assintom?ticos do sexo masculino. (2) Propor uma equa??o matem?tica para predizer o pico do consumo de oxig?nio (VO2 pico) e, (3) testar a confiabilidade dessa equa??o para essa popula??o. M?todos: No primeiro est?gio do estudo, 26 participantes realizaram o ISWT e o TECP. No segundo est?gio 50 participantes realizaram o ISWT duas vezes. Em ambos os est?gios foram avaliados VO2 pico, a frequ?ncia card?aca m?xima (FC m?x.) e o pico da raz?o de troca respirat?ria (R pico). No terceiro est?gio foram comparados os valores do VO2 pico preditos pela equa??o criada e obtidos de forma direta no ISWT. Resultados: N?o houve diferen?a significativa no VO2 pico, R pico e FC m?x. obtidos no ISWT e TECP. Os valores encontrados para o VO2 pico (r = 0,44. p = 0,002) e R pico (r = -0,53, p< 0,01) obtidos no ISWT e TECP apresentaram correla??o moderada e significativa, al?m de concord?ncia na an?lise de Bland-Altman. A velocidade da marcha foi a vari?vel que explicou 48% (R2 = 0,48, p = 0,000) da varia??o no VO2 pico no ISWT. Foi criada a equa??o VO2 previsto = 5,490 + (17,093 x Velocidade da Marcha). Os resultados obtidos pela equa??o foram comparados com os valores obtidos pelo analisador de gases e nenhuma diferen?a significativa foi encontrada entre eles. Conclus?es: Em crian?as e adolescentes do sexo masculino o ISWT ? um teste de esfor?o m?ximo com repercuss?es cardiorrespirat?rias similares ao TECP. A equa??o preditiva proposta ? uma estimativa vi?vel para predi??o do VO2 pico para essa popula??o.
Disserta??o (Mestrado Profissional) ? Programa de P?s-Gradua??o em Reabilita??o e Desempenho Funcional, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017.
The Incremental Shuttle Walking Test (ISWT) has been used to evaluate the Cardiorespiratory Fitness (CRF) of children and adolescents with different pathological conditions. It is unknown whether the cardiorespiratory response presented by asymptomatic adolescents in ISWT will be similar to that induced by CardiopulmonaryExerciseStress Test (CEPT). The aims of this study were: (1) To evaluate whether ISWT is a maximum test for asymptomatic male adolescents. (2) To propose a mathematical equation to predict peak oxygen consumption (VO2 peak) and (3) Totest the reliability of this equation on this population. Methods: In the first stage of the study, 26 participants performed the ISWT and the CEPT. In the second stage 33 participants performed the ISWT twice. In both stages, peak VO2, maximal heart rate (HR max) and peak respiratory rate (peak R) were evaluated. In the third stage, the peak VO2 values predicted by the equation created and obtained directly in the ISWT were compared. Results: There was no significant difference in the peak VO2 (p> 0.05), peak R (p> 0.05) and maximum HR obtained in ISWT and CEPT. The values found for the VO2 peak (r = 0.44, p = 0.002) and peak R (r = -0.53, p <0.01) obtained in the ISWT and CEPT presented a moderate correlation and anagreement in the analysis of Bland-Altman analysis. The gait speed was the variable that explained 48% (R2 = 0.48, p = 0.000) of the variation in the peak VO2. The VO2 peak equation = 5.490 + (17.093 x Gait Speed) was created. The results obtained by the equation were compared with the values obtained by the gas analyzer and no significant differences were found between them (p> 0.05). Conclusion: ISWT produced a cardiorespiratory response comparable to CEPT in asymptomatic male adolescents, and the developed equation presented viability to predict peak VO2 in adolescents.

La valutazione funzionale è quel processo che fornisce una valutazione delle risposte integrative che coinvolgono il sistema cardiovascolare, polmonare e muscolo-scheletrico. Essa è utile per determinare lo stato di salute e il livello di fitness individuale, per prescrivere la corretta intensità di esercizio e per monitorare i possibili cambiamenti nel tempo. I più importanti parametri fisiologici per una corretta valutazione funzionale e prescrizione dell’esercizio sono il massimo consumo di ossigeno (VO2max) e la soglia anaerobica (AT). L’obiettivo del mio precorso di dottorato è stato quello di sviluppare e validare alcuni metodi indiretti per determinare il massimo consumo di ossigeno (VO2max) e la soglia anaerobica (AT) in persone adulte ed anziane. I principali risultati della mia ricerca sono i seguenti: 1) lo sviluppo e validazione di una versione "su misura" dell’Astrand-Rhyming step test e una nuova equazione per la stima del VO2max negli anziani; protocollo e nuova equazione risultano essere adatti per una rapida (5-min), sicura (submassimale), accurata e precisa stima del VO2max in anziani sani. 2) l'AT può essere accuratamente determinata in soggetti sani sulla base della quantità di emoglobina deossigenata, indice di estrazione di ossigeno, presente a livello del muscolo vasto laterale e misurata in modo non invasivo attraverso la near infrared spectroscopy (NIRS). I principali vantaggi dell’utilizzo della NIRS per determinare AT, rispetto alle altre tecniche basate sui prelievi di lattato sono la non invasività e l’efficienza in termini di tempo e costi. 3) dal confronto di AT basata sulla tecnica NIRS con il surrogato più comunemente usato per la determinazione di AT in maniera indiretta, vale a dire le soglie ventilatorie di Wasserman (VT1 e VT2) si è visto che AT basata sulla NIRS è altamente correlata e sostanzialmente coincidente con VT1. Al contrario VT2 viene sottostimata dalla tecnica NIRS. Rispetto ad altri metodi, la NIRS offre il vantaggio dell'indipendenza dalla irregolarità della respirazione che può influire pesantemente sui metodi basati sulle tecniche ventilatorie.
The functional evaluation is the process that provides assessment of the integrative responses involving the pulmonary cardiovascular and skeletal muscle system; it is useful to determine the health status and the individual fitness level, to prescribe correct exercise intensity and to monitor the possible changes over time. The most important physiological parameters for the functional evaluation and a correct exercise prescription are the maximum oxygen uptake (VO2max) and the anaerobic threshold (AT). The aim of my PhD project was to develop and validate some indirect methods for the maximum oxygen uptake and the anaerobic threshold determination in groups of young and older adults. The main goal is the feasibility and accuracy of these new "field" methods. The main results of my research are: 1) It is developed and validated a “tailored” version of the Åstrand-Rhyming step test and a new equation for VO2max prediction in older adults; they appear suitable for a rapid (5-min), safe (submaximal), accurate and precise VO2max prediction in healthy older adults. 2) It is verified that the AT can be accurately determined in healthy subjects based on measures of deoxygenated hemoglobin, index of oxygen extraction measured non-invasively by near infrared spectroscopy (NIRS). The main advantages of NIRS-based measures of AT over lactate-based techniques are the non invasiveness and the time/cost efficiency. 3) It is compared NIRS-based measures of AT to the most commonly used surrogate of AT i.e. the ventilatory thresholds of Wasserman (VT1 and VT2); NIRS-based measures of AT was highly correlated and substantially coincident with VT1. On the contrary NIRS-based measures of AT underestimated VT2. Compared to other methods, NIRS-based measures of AT offers the advantage of the independence from irregularity of breathing pattern that can heavily affect ventilatory based techniques.

The objective of this analysis is to determine optimum parameters for maximum performance and minimum emission for biodiesel-fueled diesel engine. The experiments were designed using Taguchi L25 orthogonal array. Five parameters—fuel blend, load, speed, injection timing, and injection pressure—each with five levels were selected. Cylinder pressure, exhaust temperature, brake thermal efficiency, brake specific fuel consumption, carbon monoxide, unburned hydrocarbons, nitric oxide, and smoke were response parameters. Optimum combination of parameters was determined by grey relational analysis. The confirmatory test was performed at optimum combination. The grey relational grade and signal-to-noise ratio was determined. The contribution of individual parameter was determined by ANOVA analysis. Optimum performance was obtained at 80% load and 1900 rpm speed with B50 fuel at injection timing of 15.50 BTDC with 225 bar injection pressure. Finally, grey relational grade was improved by 3.7%.

Abstract In this paper effect of on reduction a Cu-ZSM-5 catalyst of nitrogen oxides is investigated in a diesel engine. This research focuses to solve a problem that there is not enough THC to reduce nitrogen oxides in exhaust gas from a diesel engine. When diesel oil is directly supplied into the exhaust gas, the THC concentration sharply rises and the NOx conversion rate increases. The maximum NOx conversion rate reaches to 63% when the flow rate of diesel oil is 30 ml/min at a catalyst temperature 450 °C. The NOx reduction with less sacrifice of the specific fuel consumption is possible when the fuel is supplied into the exhaust pipe.

Exhaust gas recirculation (EGR) combined with particulate trap technology has proven to reduce nitrogen oxides (NOx) and smoke emissions simultaneously at relatively low cost compared to other reduction strategies. An experimental study was conducted on a single cylinder, direct injection (DI) diesel engine to study the effect of EGR on engine performance and emissions under constant speed of 1500 rpm at various loads. In the present work hot and cool EGR were used to control the formation of NOx in a D.I diesel engine. The findings of both hot and cool EGR are discussed and compared at full load condition corresponding to the maximum allowable EGR proportion of 15%. It is found that cool EGR has a substantial reduction in NOx and smoke emissions compared to hot EGR. Based on the above result it is found that suitable particulate trap which is cost effective and high trapping efficiency is needed before the EGR cooler to reduce the smoke emissions to meet the emission standards. In the present study a substrate made of clay material was used in the particulate trap. They were made into spheres and coated with copper and zinc oxide catalyst material. The results have shown that EGR combined with particulate trap simultaneously reduces the NOx and smoke emissions by 63% and 42% respectively where as it increases brake specific fuel consumption by 10% compared to baseline mode.

In this experimental examination, an attempt was made to improve the performance and diminish the exhaust emissions by adding titanium oxide (TiO2) nanoparticles into J30D5H blend (5% by volume n-hexane, 30% by volume jojoba methyl ester, and 65% by volume diesel fuel) under various engine loads and a constant speed of 2000 rpm. The titanium oxide nanoparticles were added to J30D5H blend at two proportions, including 25 mg/l and 50 mg/l by using an ultrasonic technique. The addition of TiO2 into J30D5H led to a significant improvement in the engine performance, where the brake specific fuel consumption was reduced by 12%, while the brake thermal efficiency was increased by 15% compared to J30D5H blend. The combustion consequences for the J30D5H blend with nanoparticles addition exhibited that the peak pressure and maximum heat release rate were increased by approximately 4.5% and 2%, respectively. Moreover, the CO and UHC emissions were reduced by 20% and 50%, respectively. Nevertheless, the NOx emission was increased by about 15% with adding TiO2 into J30D5H blend.

Abstract The objective of this work is to discuss design considerations related to the development of a stand-alone photovoltaic driven hydrogen production and consumption system. The referred system is currently on the design-phase so this work describes in particular the associated design considerations, governing equations, schematics and the expected system efficiency. The system design requirements include the production of enough energy to power an average residence located in the Ica city, Peru. The system design has been divided in four subsystems, each one having its own design considerations and limitations, (i) power, hydrogen (ii) production, (iii) storage and (iv) consumption. Regarding the power subsystem, the required considerations to generate the maximum amount of solar energy in the minimum amount of space are presented. For hydrogen production, different electrolyzer related technologies have been accounted for; including proton exchange (PEM), alkaline (AEC) and polymer (PEC). Hydrogen and oxygen storages are a critical aspect in the full hydrogen chain production. Currently no single technology satisfies all of the criteria required. As such, present technologies and selection considerations are presented. For using the produced hydrogen, fuel cell stacks including PEM and solid oxide ones are assessed. Finally, the right the combination of current, voltage (including conversion from DC to a constant AC supply) and fuel utilization maximizing efficiency and power output is determined.

The retrofitting projects have been considered in many countries to convert simple gas turbine units into more advanced cycle units with higher efficiency and higher output. Among many proven technologies, such as inlet air cooling, intercooling, regeneration, reheat and steam injection gas turbine etc., pulse combustion is one of the promising technologies in boosting both the output capacity and thermal efficiency, and reducing carbon and nitrogen oxides emissions without additional pollution control equipment. This paper presents the analysis of potential and real benefits of pulse combistion technology applied in the combustion process of a simple gas turbine cycle under different operating conditions. In addition, this study investigates the utilization of converting part of chemical energy of fuel into pressure energy in the gas turbine pulse combustion chamber. The influence of the maximum pressure rise due to pulse combustion (pre-compression parameter), the ratio of combustion heat released in the isochoric process, maximum cycle temperature, and compressor pressure ratio on the performance paramenters such as net work output, cycle thermal efficiency, and fuel consumption were also investigated. Finally, the results of comparative analyses between a simple gas turbine cycle utilizing a pulse combustor and a conventional cycle show the thermodynamic advantages of applying this technology in simple gas turbine power cycles.

This investigation focused on the combustion and performance of an indirect injection (IDI) diesel engine powered by a non-edible biodiesel blend, Brassica Carinata. This oilseed has become an attractive non-edible feedstock for biodiesel in the United States, given potential agronomical advantages. A small bore, single cylinder IDI engine was run at 2000 rpm and 5.5 bar indicated mean effective pressure (IMEP) using ultra-low sulfur diesel #2 (ULSD#2) and compared with C50, a 50% Carinata biodiesel-ULSD#2 blend (by mass). The apparent heat release for C50 reached a maximum of 22.04 J/deg which was 6.3 % lower and peaked 1.80 CAD before ULSD#2. The radiation and convection heat fluxes had similar maximum values of 0.62 MW/m2 and 1.34 MW/m2, respectively. The brake specific fuel consumption (BSFC) of C50 was 211.05 g/kWh, which was 9% higher than for ULSD#2. The mechanical efficiency was maintained relatively constant at 55% while the indicated thermal efficiency of the engine reached 59%. Both fuels produced similar nitrogen oxide (NOx) emissions with ULSD#2 and C50 producing 2.29 g/kWh and 2.23 g/kWh, respectively. The results indicate that the IDI engine can optimally work with concentrations up to 50% biodiesel.

A twin cylinder, constant speed, direct injection CI (diesel) engine was run on jatropha biodiesel and diesel fuel blends. The engine was directly coupled to a hydraulic dynamometer whose load was varied by adjusting load wheel on the top of the engine. The test results were recorded for pure diesel, pure biodiesel (B100) and different diesel/biodiesel blends. The performance characteristics shows that brake specific fuel consumption (BSFC) decreases rapidly with increase of load up to 4.0 to 4.5 kW (55% to 62% of full load) and then decreases slowly. This result also indicates that BSFC increases when the percentage of biodiesel in the blends is increased. Brake thermal efficiency also increases from high biodiesel blends to pure diesel fuel. Each fuel curve shows maximum efficiency reaches at the load range of 5.0 to 5.5 kW (68% to 75% of full load). Pure diesel has maximum efficiency 29.6%, where as pure biodiesel has maximum efficiency of 21.2%. The exhaust gas temperature increases with the load for all fuel blends. Pure biodiesel gives higher exhaust temperature (320°C) than pure diesel (260°C). The exhaust gas temperature increases with the higher percentage of biodiesel blends in different fuel blends. The probable reason for that is biodiesel contains oxygen atoms which make the combustion process complete and hence more energy is released. In respect of emission characteristics, carbon mono-oxide (CO) and hydrocarbon emissions are improved with the addition of biodiesel to diesel. But these emissions increase with the increase of load for all fuel blends. NOx emission increases with load as well as percentage of blending of biodiesel in the diesel fuel.

NASA Dryden Flight Research Center has completed a preliminary performance analysis of the SR-71 aircraft for use as a launch platform for high-speed research vehicles and for carrying captive experimental packages to high altitude and Mach number conditions. Externally mounted research platforms can significantly increase drag, limiting test time and, in extreme cases, prohibiting penetration through the high-drag, transonic flight regime. To provide supplemental SR-71 acceleration, methods have been developed that could increase the thrust of the J58 turbojet engines. These methods include temperature and speed increases and augmentor nitrous oxide injection. The thrust-enhanced engines would allow the SR-71 aircraft to carry higher drag research platforms than it could without enhancement. This paper presents predicted SR-71 performance with and without enhanced engines. A modified climb-dive technique is shown to reduce fuel consumption when flying through the transonic flight regime with a large external pay load. Estimates are included of the maximum platform drag profiles with which the aircraft could still complete a high-speed research mission. In this case, enhancement was found to increase the SR-71 payload drag capability by 25 percent. The thrust enhancement techniques and performance prediction methodology are described.

This paper focuses on quantifying emission reductions associated with various on-engine technologies applied to Electro-Motive Diesel two-cycle diesel engines, which are very popular in marine and locomotive applications in North America. This paper investigates the benefits of using exhaust gas recirculation (EGR), separate circuit aftercooler, and retarded injection timing on a EMD 12-645E7 marine engine. The EGR system alone provided up to a 32.9% reduction in brake specific Nitrogen Oxides (NOx) emissions while demonstrating less than one percent increase in cycle brake specific fuel consumption (BSFC). The brake specific particulate matter emissions increased somewhat, but at a modest rate based on the amount of NOx emission reduction. When the enhanced aftercooler system was combined with the addition of EGR, there was a 31.9% reduction in NOx and essentially no change to the BSFC when compared to the baseline test. The minimum manifold air temperature (MAT) was limited due to the size of the standard EMD aftercooler heat exchanger that is fitted on the engine. No efforts to modify the turbocharger to improve the turbo match to take advantage of the lower manifold air temperatures and the corresponding lower exhaust energy. Once 4° static injection timing retard was introduced, along with the EGR and the minimum MAT, a maximum NOx reduction of 49% was realized with only a 1.1% increase over the baseline BSFC.

The use of biodiesel substantially reduces particulate matter (PM), hydrocarbon (HC) and carbon monoxide (CO) emissions, slightly reduces power output; increases fuel consumption and marginally increases oxides of nitrogen (NOx) emission in an unmodified common rail direct injection (CRDI) diesel engine. Lower blends of biodiesel demonstrated lower emissions, while easing pressure on scarce petroleum resources, without significantly sacrificing engine power output and fuel economy. However due to adverse health effects of smaller size particulate matter (PM) emitted by internal combustion (IC) engines, most recent emission legislations restrict the PM mass emissions in addition to total particle numbers emitted. It is an overwhelming argument that usage of biodiesel leads to reduction in PM mass emissions. In this paper, experimental results of PM emissions using Karanja biodiesel blends (KB20 and KB40) in a modern CRDI transportation engine (maximum fuel injection pressure of 1600 bar) have been reported. This study also explores comparative effect of varying engine speed and load on PM emissions for biodiesel blends vis-à-vis baseline mineral diesel. Particulate size-number distribution, particle size-surface area distribution and total particulate number concentrations were experimentally determined under varying engine operating conditions and compared with baseline mineral diesel. KB20 showed highest particulate number concentration upto 80% rated engine loads, however at rated load, KB40 emitted highest number of particulates.