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1
BOUSSADIA, AFEF. « Modelli di crescita di Orate in allevamenti marini ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2018. http://hdl.handle.net/10281/207341.
Texte intégralRésumé :
L’Orata (Sparus aurata) è una delle specie più allevate in gabbie nel mare Mediterraneo. Nelle gabbie, i pesci di allevamento sono esposti a variazioni stagionali della temperatura dell'acqua e queste variazioni possono differire da un luogo all'altro. Gestire il sistema di crescita richiede una buona conoscenza dei fattori che interessano la crescita del pesce, come lo stato del pesce, la disponibilità dell’alimentazione e la gestione del pesce dal momento in cui viene stoccato al momento in cui viene pescato. Questo studio è un tentativo di valutare questi fattori ed è stato svolto presso un vivaio per l’allevamento di orate, situato nella parte sud del Mar Mediterraneo, in Tunisia. Esso vuole mostrare l'interazione tra i tassi funzionale come il rapporto di conversione di alimentazione, il tasso di crescita specifico e il tasso di alimentazione specifico e dimostrare la loro dipendenza dalle fluttuazioni della temperatura dell'acqua.
Le variazioni della temperatura dell'acqua vengono misurate giornalmente e il monitoraggio dei parametri di crescita è stato applicato per ventuno gabbie di orate allevate per sei anni consecutivi, al fine di confrontare i risultati con e senza un andamento nella serie temporale.
Il presupposto da cui si è partiti è che la crescita dei pesci sia influenzata da tre fattori fondamentali: il peso, la temperatura dell'acqua e il tasso di alimentazione specifico. Questi fattori controllano il tasso di crescita specifico e di conseguenza il coefficiente di trasformazione del mangime.
Un modello basato sulla temperatura e sul tempo che preveda la crescita dei pesci potrebbe essere utilizzato per valutare gli effetti della quantità di alimentazione somministrata sulle prestazioni dei pesci e per dimostrare che il tasso di alimentazione può essere un vincolo per l'efficienza dei modelli di crescita, che combina diversi fattori.Gilthead sea bream (Sparus aurata) is one of the most cultured species in marine cages in the Mediterranean Sea. In sea cages, farming fish are exposed to seasonal variations of water temperature and these variations can differ from one location to another. Managing the growing system requires a good knowledge of factors affecting the growth of fish, as fish status, feed availability and fish handling from the stocking time to the harvesting time. This study is an attempt to assess these factors at a marine fish farm of Gilthead sea bream, located at the south part of the Mediterranean Sea, in Tunisia. The study aims to demonstrate the interaction between performance rates, as feed conversion rate, specific growth rate and specific feeding rate and demonstrating their dependency on water temperature fluctuations. Water temperature variations are measured daily, and the monitoring of growth parameters was applied for 21 marine cages of sea bream reared for six consecutive years, in order to compare results with and without a trend in the time series. We assume that fish growth is influenced by three fundamental factors: fish weight, water temperature and specific feeding rate. These factors control the specific growth rate and consequently the feed conversion rate. Model predicting the growth, based on temperature and time, is used to evaluate the effect of feeding rate on fish performance and to demonstrate that feeding rate could be a constraint for growth models efficiency, combining several factors.
2
Cox-Richard, Lillian. « Spark Gap ». VCU Scholars Compass, 2008. http://scholarscompass.vcu.edu/etd/698.
Texte intégralRésumé :
"Spark Gap" is an invisible electrical force made visible in spaces between things. This usually describes the space of air between two conductors; a non-conductive gap in an otherwise complete electric circuit, across which a quick luminous disruptive electrical discharge occurs. This interstitial space is the distance between two ideas, arced with a running leap. The arc can also be the difference between two things, a gap that becomes apparent only when the two are held in close proximity. In my thesis exhibition, "Spark Gap," a sea urchin shaped orb sits atop a tower of ladders. The orb is broken into five sections and reassembled, each fault line occurring along the perfect zigzag line of its cellular structure. On the floor, there is a linen shag rug, marked as if struck by lightning. This exhibition is named for an interstitial charge, arcing across distance or difference. But this charge is also found in intersections and similarities. Imagine the friction created by rubbing together the circles of a Venn diagram: the overlapping section would begin to spark. It is in these gaps and overlaps that I find the impetus for my work.
3
Monastyrsky, G. E., P. Ochin, A. V. Gilchuk et V. I. Kolomytsev. « Spark plasma sintering the spark-erosion powders of functional alloys ». Thesis, Sumy State University, 2011. http://essuir.sumdu.edu.ua/handle/123456789/20798.
Texte intégralRésumé :
Various shape memory alloys (Ti-Ni-Hf, Ni-Al and Cu-Al-Ni) were elaborated by
spark plasma sintering method from the micron, submicron and nano- sized particles
prepared by spark-erosion method in cryogenic liquid from preliminary melted master
alloys. These alloys are being developed as one of the alternatives for the intermediate
temperature applications (100-900oC). Spark plasma sintering method is express
method, which provides lower temperature and shorter holding time of sintering. It
makes possible to sinter materials from the pre-alloyed powders and eliminate the
intensive grains growth and precipitating processes influencing the mechanical and
functional properties of functional materials. The effects of processing parameters on the
martensitic transformation and microstructure of the sintered compacts were
investigated using XRD and SEM study. Temperatures of sintering were chosen
according to the assessed data of the decomposition, oxidation and others processes
carrying out in material. Although the precipitating processes were usually not
completely depressed, the intensive grain growth was also not found in most cases. Most
of the microstructure peculiarities of as processed powder were inherited by the sintered
material.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/20798
4
Boeckx, W. D. « Recycling spare parts ». Maastricht : Maastricht : Maastricht University ; University Library, Maastricht University [Host], 1999. http://arno.unimaas.nl/show.cgi?fid=13042.
Texte intégral
5
Kim, Kwanghoon. « Infrared luminescence from spark-processed silicon and erbium-doped spark-processed silicon ». [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0012860.
Texte intégral
6
Walls, Kate. « Muriel Spark and Catholicism ». Thesis, Queen's University Belfast, 2014. https://pure.qub.ac.uk/portal/en/theses/muriel-spark-and-catholicism(2d16b200-588b-4866-a1d6-dea6396b68cb).html.
Texte intégralRésumé :
My PhD thesis analyses Catholic themes in the novel,s of Scottish born writer Muriel Spark. Spark's career spanned five decades, and much of her work was influenced by her conversion to Catholicism. She is a sophisticated and enigmatic writer whose work defies categorisation. Part of this difficulty stems from her position as "other" within Catholicism· -a result of her conversion and her refusal to adhere to traditional Catholic gender roles. What does become clear upon examining Spark's fiction is that she uses subversive and paradoxical rhetoric to highlight the problems inherent in being unable to fully comprehend God's mystery. Spark appears to be obsessed with several religious concepts that appear constantly in her fiction. In the case of the Catholic convert and the Book of Job, these threads appear repeatedly and build to a climax-once Spark comprehensively addresses them in her fiction, the threads disappears from her work entirely. In exploring these Catholic themes, it becomes clear that, despite Spark's work being abundant with references to religion, there is very little narrative space devoted to the character's internal thoughts regarding God and religious thought. I argue that in Spark's fiction, creativity is a proxy for religious faith. Spark draws parallels to the personal and individual nature of both, but devotes more narrative space to explaining a sense of faith in the creative process. She also appears to grant narrative endorsement to characters who believe in and ate guided by their creativity, even when they clearly traverse the boundaries of acceptable "moral" behaviour.
7
Mahajan, Rohan. « Adaptive scheduling in Spark ». Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/105977.
Texte intégralRésumé :
Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (page 33).
Because most data processing systems are distributed in nature, data must be transferred between machines. Currently, Spark, a prominent such system, predetermines the strategies for shuffling this data, but in certain situations, different shuffle strategies would improve performance. We add functionality to track metrics about the data during the job and appropriately adapt the shuffle strategy. We show improvements in ShuffledRDD performance, joins using Spark's RDD interface, and joins in Spark SQL.
by Rohan Mahajan.
M. Eng.
8
Blom, Jonas. « Optimizing spare-parts management ». Thesis, Högskolan i Gävle, Industriell ekonomi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-28822.
Texte intégralRésumé :
Abstract Purpose: The purpose of the study is to develop a model that will facilitate the choice of maintenance strategy within the Swedish pulp and paper industry. Without compromising system availability, the model aims to reduce inventory holding costs. Methodology: At first, a literary research was conducted to create a holistic view over the chosen topic, in time it developed into a literature framework. Secondly, a case study was conducted in order to obtain empirical data. The data were obtained through interviews and archival records. The literature framework and the empirical data were then cross-analyzed with each other. Findings: In this thesis, a model has been developed based on previously applied and accepted methods. The methods have been identified and described in order to provide a strategy in which the inventory levels- and value could be lowered. The findings indicate that the organization must seek to assign ABC-classified and VED-analyzed components different maintenance actions in order to reduce the total cost. Theoretical contribution: This thesis contributes to a methodology development regarding spare parts management. It aims to add knowledge to the existing gap regarding spare parts order point and batch size. The thesis provides a procedure in which systems including critical and expensive components are evaluated in order to assign them the appropriate maintenance. Practical relevance: The model has only been exemplified by using a system position from Stora Enso Skutskär, the numerical values are examples. The model must be tested with real values and the risk analysis must be carried out with a group of employees with great insight regarding the selected component and system position. Limitations: This thesis is delimited to spare parts management and inventory management. The study only involves one Swedish organization, whereas the organization and its spare parts management illustrates the complexity concerning spares. The model will not be verified as the focus is to highlight the research gap and to develop the model.
9
Häusner, Eva-Maria. « Att spara eller inte spara ? : En kvantitativ enkätstudie av informationslagringssystem för vetenskapliga artiklar ». Thesis, Uppsala universitet, Institutionen för ABM, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-174967.
Texte intégralRésumé :
Abstract Purpose This thesis aims to focus on how master students administer scholarly articles after they have found them. The purpose of the study is to detect how and to what extent people administer their articles from a personal information management-perspective (PIM). Method To answer the research questions, a web-based questionnaire survey was distributed which was announced to around 2,000 master students from different universities in Sweden. Most of the items in the survey focused on individual storage methods. The respondents were asked to rate the frequency of their different information administration behaviors on a seven level Likert-type-scale. Subsequently, items concerning specific information administration behaviors were posed, followed by questions on the respondent's sociodemographic status. The results were based on overall 316 answers. Analysis The quantitative data was analyzed using non-parametric tests such as Friedmans-test, Kruskal-Wallis-analysis, Wilcoxon-Signed Rank-test, Mann-Whitney-U-test and Chi-square-test with the statistical computer program SPSS. Findings The findings generally confirm that the majority of the surveyed graduate students are using scholarly articles. Regarding their information management, it is as usual to store the whole article as it is to store the reference. Further it is more common to choose electronic storage methods for articles and references than to use physical methods. The results highlight that most of the students use several method types and use them to varying extent. Neither age, computer skills, duration of study or satisfaction with their way of information storage influenced the quantity of used methods. Regarding specific handling, the storing of article copies on the computer’s hard drive were most frequently used. The respondents preferred furthermore to read the articles on a screen rather than printed paper versions. The influencing factors of gender, age, computer skills, subject discipline were affecting the choice of methods. General conclusions about these influencing factors are, however, complicated by possible occurring confounders. Moreover, the method types were used to different extents depending of subject discipline. Originality/value Most previous PIM research is concentrating on how people store information in general. The dealing and administrating with specific types of information are, however, rarely discussed. In the context of scholarly articles did research predominantly focus on seeking structures and reading patterns. The step between finding and reading an article has so far not directly been addressed in academic research. The study therefore is unique in addressing information storage systems of scholarly articles on such a large scale. Knowledge about storage patterns will help journal publishers and librarians to design more targeted solutions for journal systems and improve services like courses in information seeking. Paper type Two years master’s thesis
10
Lau, Pik-yuk Cecilia, et 劉碧玉. « SPARC and SPARC-like 1 are associated with tumor angiogenesis in hepatocellular carcinoma ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B30284648.
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Harnesk, Malin. « Att spara eller inte att inte spara ? : En paneldatastudie över bestämningsfaktorer för hushållens sparkvot ». Thesis, Umeå universitet, Nationalekonomi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-118707.
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12
Karlsson, Robin. « Att spara eller inte spara : En jämförelsestudie i formmaterial vid gjutning av Prefab element ». Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-21667.
Texte intégralRésumé :
Syftet med denna studie är att undersöka för vilka byggen det är mer ekonomiskt lönsamt för leverantör av prefabelement att använda sig utav engångsskiva eller formplyfa som formmaterial. I uppdrag av UBAB har en undersökning gjorts om vilket formmaterial som är det lönsammare alternativet vid produktion av trappor. Detta har gjorts genom att analysera processernas tidåtgång, materialkostnad samt totalkostnad. Arbetssätten skiljer sig mellan de olika formmaterialen och därför har arbetsmomentet kartlagts genom tidsstudier för indata och observationer för ytterligare förståelse om processerna. Genom intervjuer har en materialåtgång framkommit som tillsammans med informationen från tidsstudierna använts för att ta fram totalkostnaden. Resultatet visar att totalkostnaden för engångsskivan är större än vid användandet av den traditionella formplyfan. Endast första gjutet visar sig vara lönsammare med engångsskivan. För att engångsskivan ska vara ett kostnadseffektivt alternativ vid flera gjut behövs materialåtgången sänkas då kostnaden för den snabbt blir dubbelt så dyr som med formplyfan. Även om kostnaden för engångsskivan är större finns fortfarande fördelar och möjligheter till förbättring. Att utveckla standardiserade arbetssätt även för engångsskivan kan göra det mer tidseffektivt och genom att få ner materialåtgången kan göra engångsskivan till ett mer lönsamt alternativ.The purpose of this study is to determent what type of build it’s more economic profitable for the supplier of prefab element to use single-use sheets or form plywood as mold material. Tasked by UBAB a survey was made to see which of the mold materials’ the most profitable alternative in production of stairs. This was made through analyzing the processes time consumption, material cost and total cost. Working procedure is different between the mold materials and that is why the operations been charted through time studies for input and observations for a greater understanding of the processes. A material consumption has emerged through interviews that together with the information from the time studies been used to determent the total cost. The result shows that the total cost for the single-use sheet is greater than when using the traditional form plywood. Only the first cast turns out to be more profitable with the single-use sheet. For the single-use sheet to be a cost efficient alternative at multiple casts the material consumption must be lowered since the cost quickly becomes twice as expensive as form plywood. Even though the cost of single-use sheets is greater there are still benefits and possibilities for improvement. To develop standardized working procedures for the single-use sheet as well could make it more time efficient and by decreasing the material consumption could make the single-use sheet a more profitable alternative.
13
Ni, Ze. « Comparative Evaluation of Spark andStratosphere ». Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-118226.
Texte intégralRésumé :
Nowadays, although MapReduce is applied to the parallel processing on big data, it has some limitations: for instance, lack of generic but efficient and richly functional primitive parallel methods, incapability of entering multiple input parameters on the entry of parallel methods, and inefficiency in the way of handling iterative algorithms. Spark and Stratosphere are developed to deal with (partly) the shortcoming of MapReduce. The goal of this thesis is to evaluate Spark and Stratosphere both from the point of view of theoretical programming model and practical execution on specified application algorithms. In the introductory section of comparative programming models, we mainly explore and compare the features of Spark and Stratosphere that overcome the limitation of MapReduce. After the comparison in theoretical programming model, we further evaluate their practical performance by running three different classes of applications and assessing usage of computing resources and execution time. It is concluded that Spark has promising features for iterative algorithms in theory but it may not achieve the expected performance improvement to run iterative applications if the amount of memory used for cached operations is close to the actual available memory in the cluster environment. In that case, the reason for the poor results in performance is because larger amount of memory participates in the caching operation and in turn, only a small amount memory is available for computing operations of actual algorithms. Stratosphere shows favorable characteristics as a general parallel computing framework, but it has no support for iterative algorithms and spends more computing resources than Spark for the same amount of work. In another aspect, applications based on Stratosphere can achieve benefits by manually setting compiler hints when developing the code, whereas Spark has no corresponding functionality.
14
Bútora, Matúš. « Modelem řízený vývoj Spark úloh ». Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2019. http://www.nusl.cz/ntk/nusl-403168.
Texte intégralRésumé :
The aim of the master thesis is to describe Apache Spark framework , its structure and the way how Spark works . Next goal is to present topic of Model- Driven Development and Model-Drive Architecture . Define their advantages , disadvantages and way of usage . However , the main part of this text is devoted to design a model for creating tasks in Apache Spark framework . Text desribes application , that allows user to create graph based on proposed modeling language . Final application allows user to generate source code from created model.
15
Kim, Jaecheol. « The role of radicals supplied directly and indirectly on ignition ». Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53001.
Texte intégralRésumé :
The ignition process is a critical consideration for combustion devices. External energy transfer to the combustor is required for ignition in common combustion systems. There are many ways to deposit energy into the flow but a standard method is a spark discharge because it is simple, compact, and reliable. Sparks can be categorized as either inductive or capacitive sparks that use a coil or an electrical resonance circuit with capacitor, respectively, to amplify the voltage. The creation of a successful ignition event depends on the spark energy deposited into the flow, the initial composition, pressure, temperature, turbulence level of flow etc. The deposited energy by the spark into the flow is critical for estimation of initial energy available for ignition of the mixture. Therefore, the electrical characteristics of the sparks were investigated under various flow conditions. Then measurements of deposited energy into the flow were conducted using a very accurate experimental procedure that was developed in this research. The results showed considerable electric energy losses to the electrodes for the relatively long, inductive sparks. However, the short, capacitive spark deposits electric energy into the flow with minimal loss (above 90% deposition efficiency). In addition, the characteristics of inductive spark are affected by flow velocity and by the existence of a flame. However, variations in the flow conditions do not affect the characteristics of the capacitive spark such as voltage-current time trace and energy deposition efficiency.
Two ignition systems using above mentioned two spark types were developed. First, the capacitive spark energy was directly deposited into the premixed flow. Most researchers have not concentrated on the early initiation process but on the flame growth. Therefore, the generated kernel formed by the energy deposition was observed and characterized using optical methods, immediately following the spark. In addition, the mixing effect for this ignition kernel with surrounding gas was simulated using a numerical method. Based on the time trace of the OH* chemiluminescence, the reaction starts with the discharge and it is continuous until combustion begins. This means that in the presence of a high density spark in premixed flow, there exists no traditional delay as defined by other researchers for auto ignition.
A simple Radical Jet Generator (RJG) was developed that is able to ignite and stabilize a flame in a high-speed flow. The inductive spark initiates the combustion in the RJG chamber. The RJG then injects the partially-burned products carrying large amounts of heat and radicals into a rapidly moving flammable main stream. Then it ignites and stabilizes a flame. The RJG requires low levels of electrical power as long as the flow velocity is relatively low since most of the radicals are produced by the incomplete combustion in its chamber. The importance of radicals was analyzed by RJG experiments and numerical methods. The reaction zone for RJG using a rich mixture was located both inside and outside of the RJG chamber. Therefore, the RJG using a rich mixture performed better in the ignition and stabilization of combustion in the main flow. According to an analysis using the CHEMKIM simulation software combined with the San Diego chemical mechanism, the RJG jet resulting from a rich mixture contains more radicals and intermediates than that produced by a lean mixture for the same sensible enthalpy. In addition, the burned gas contains less radicals and intermediates than the partially burned gas.
If the RJG is operating with a high speed main flow, the flow rate through the RJG chamber must be increased to allow the radical jet to penetrate well into the rapid flow due to their higher injection velocity. Unfortunately, this leads to unsteady combustion in the RJG, which results in the pulsation of the radical jet. This reduces the number of radicals injected into the main flow. To investigate this operating condition, special attention was focused on four possible factors: unburned reactant pockets caused by motion of the spark channel, spark frequency, flame propagation speed and ignition delay. It was shown that the unsteadiness is affected by the flame speed and ignition delay because the frequency of pulsation in the chamber is highly dependent on the equivalence ratio. In addition, the interaction between the RJG operation and the combustion dynamics in the main combustor was documented. The acoustic pressure oscillations in the main combustor were suppressed when the RJG jet was turned on because the reaction region is relocated by the operation of the RJG.
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Schäfer, Lukas [Verfasser]. « Modeling and Simulation of Spark Ignition in Turbocharged Direct Injection Spark Ignition Engines / Lukas Schäfer ». München : Verlag Dr. Hut, 2016. http://d-nb.info/1106593502/34.
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Parmenter, David Charles. « Spark Ignition and Spark Assisted Controlled-Auto Ignition in a Top Entry Direct-Injection Gasoline Engine ». Thesis, University of Brighton, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485951.
Texte intégralRésumé :
An experimental study of the mixture preparation and combustion characteristics of a direct injection gasoline (G-DI) engine operating in both spark ignition (SI) and controlled-auto ignition with spark assistance (SA-CAl) is presented. The air motion, fuel distribution and combustion performance in the engine are described by the application of advanced Laser-based experimental methods and high-speed data acquisition. Determining the correct operation of the engine for spark ignition and compression ignition formed an important part of the research study. The series of experimental studies were conducted on a Ricardo Hydra singlecylinder research engine modified for optical access through the top 20mm section of the cylinder bore, as well as via a 45° mirror and flat window inserted in the crown of the Bowditch piston arrangement. The cylinder head used was based on the Ricardo Flagship concept engine with reverse tumble geometry. Two different interchangeable camshaft sets permitted both high and low valve lift configurations to be utilised. Spark ignition (SI) and controlled-auto ignition with spark assistance (SA-CAl) were achieved in the test programme. Laser-induced fluorescence (L1F), combined with simultaneous flame imaging and Particle Image Velocity (PIV) enabled qualitative in-cylinder fuel concentration measurement during fired operation and quantitative motored air motion characteristics to be determined. Simultaneous acquisition of pressure-based data during the fired studies provided a record of the in-cylinder, intake and exhaust manifold pressures. The addition of K-type thermocouples provided additional temperature information in the engine. The results attained using the above techniques showed that rates of heat release in the SA-CAl combustion mode were considerably slower than those observed in a parallel SI combustion study. This suggested that a key indicator of controlled-auto ignition (CAl) was not present in this study; it is widely considered that CAl heat release rates are of the order of those encountered in SI, when considering 4stroke operation. This result implied that flame-front propagation was the governing mechanism of fuel oxidisation in the SA-CAl mode. However, the results of the PIV studies in the SA-CAl mode suggested that the turbulence intensity was too low to support flame-front propagation in spark-initiated combustion. High-speed photography (HSP) applied in addition to the previously mentioned techniques showed that a hybrid mode of combustion exists in the SA-CAl reaction where flame front propagation could be seen to develop alongside individual sites of autoignition within the cylinder, albeit at a considerably lower rate. Images of fuel distribution in the combustion chamber acquired from the previous studies were correlated to pressure-based combustion stability data. A statistical analysis was conducted of both the SI and SA-CAl sets of data in order to determine cyclic variability within the in-cylinder fuel concentration. The results indicated higher than expected cycle-to-cycle and in-cycle variations in fuel distribution for an early injection, homogeneous charge, combustion mode when compared to those based upon the coefficient of variation in the measured indicated mean effective pressure. The L1F data. from the SA-CAl studies was found to be of far lower intensity, suggesting that the presence of high levels of exhaust residuals acted to attenuate the fluorescence signal. These findings were of particular importance to the application of the L1F technique in this manner. From the findings of the experimental techniques applied it was possible to determine from the mode of combustion encountered, SA-CAl, that a hybrid mode of fuel oxidation was occurring. It was clear that flame-front propagation was taking place, albeit at a far slower rate than in the corresponding Sl mode, as both high EGR rates and lower turbulence intensity was found to attenuate flame propagation, with further heat release occurring through diffusion burning and numerous autoignition points throughout the cylinder through the thermal energy supplied from the resident internal EGR.
18
Ogboo, Adanma Nelo. « THE GEOGRAPHY OF AUTOMOBILE SPARE PARTS TRADE : ASPMDA AND LADIPO AUTOMOBILE SPARE PARTS MARKETS, LAGOS, NIGERIA ». Miami University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=miami1313490568.
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Lodi, Faisal Samad. « Reducing cold start fuel consumption through improved thermal management ». Connect to thesis, 2008. http://repository.unimelb.edu.au/10187/3601.
Texte intégralRésumé :
The thesis presents research in achieving faster warm-up of an SI engine, thereby affecting the fuel economy penalty. The faster warm-up relates to faster heating of the cylinder head and engine block, targeting reducing viscous friction in the cold oil as the most likely candidate to improve. The strategy applied was to reduce the coolant flow circulation rate to achieve a faster warm-up of the engine. A lumped parameter model for engine heat transfer, coolant flow and heat capacities, in a single cylinder, based on engine operating points like spark advance, engine speed and MAP was built in Modelica.The engine used for experimentation was a Ford in-line, 4 stroke, 6-cylinder engine, with a compression ratio of 10.3:1, in which 56 K-type thermocouples were installed at different locations to measure the temperature. The experiments were performed with varying coolant flow rate from normal down to zero, utilizing an electric water pump, over an approximation to the New European Drive Cycle (NEDC), at a speed of 1161 rev/min and load of 48 Nm. The selected speed and load were the average operating condition for 180 seconds of engine running over the urban part of a simulated NEDC. In addition, the coolant circuit was modified to a split cooling supply and the sets of results analyzed to find the reduction in engine warm-up time and fuel consumption.
It is shown from the results that the warm-up time of the engine and the fuel consumption were notably reduced, as the flow was reduced from maximum to minimum in steps. On average over an interval of engine running for 300 seconds from cold start, the cylinder head temperature was increased by about 2°C , the average engine block temperature was increased by about 6.5°C and the average cylinder head coolant temperature was increased by about 4°C . However, the bulk temperature of the oil in the oil sump showed marginal improvement and remained consistent, even at the lowest coolant flow rate. Nonetheless, the improvements in block temperature had significant effects on reducing the friction between the piston and cylinder walls.
Analysis of the results show that the coolant flow pattern changed with the use of an electric water pump. The flow is less evenly distributed around the cylinders with the use of an electric water pump, whilst retaining the mechanical water pump body, compared to the mechanical water pump operation.
The model was applied to simulate for two engine operating points, i.e., 1161 rev/min, 48 Nm load and 700 rev/min and 0 Nm load. The model was calibrated at 1161 rev/min, 48 Nm load and validated at 700 rev/min, 0 Nm load. The modeling results were in fair agreement with the experimental results. The model can be employed to investigate electric water pump control.
The important finding is that around 3% fuel consumption savings are possible over the NEDC by management strategies that lead to faster cylinder block warm up, even though this may result in little or no change in oil temperature as measured in the sump.
20
Gatto, Lorenzo. « Analisi e valutazione della piattaforma Spark ». Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8876/.
Texte intégralRésumé :
Negli ultimi anni i dati, la loro gestione e gli strumenti per la loro analisi hanno subito una trasformazione. Si è visto un notevole aumento dei dati raccolti dagli utenti, che si aggira tra il 40 e il 60 percento annuo, grazie ad applicazioni web, sensori, ecc.. Ciò ha fatto nascere il termine Big Data, con il quale ci si riferisce a dataset talmente grandi che non sono gestibili da sistemi tradizionali, come DBMS relazionali in esecuzione su una singola macchina. Infatti, quando la dimensione di un dataset supera pochi terabyte, si è obbligati ad utilizzare un sistema distribuito, in cui i dati sono partizionati su più macchine.
Per gestire i Big Data sono state create tecnologie che riescono ad usare la potenza computazionale e la capacità di memorizzazione di un cluster, con un incremento prestazionale proporzionale al numero di macchine presenti sullo stesso. Il più utilizzato di questi sistemi è Hadoop, che offre un sistema per la memorizzazione e l’analisi distribuita dei dati. Grazie alla ridondanza dei dati ed a sofisticati algoritmi, Hadoop riesce a funzionare anche in caso di fallimento di uno o più macchine del cluster, in modo trasparente all’utente.
Su Hadoop si possono eseguire diverse applicazioni, tra cui MapReduce, Hive e Apache Spark. É su quest’ultima applicazione, nata per il data processing, che è maggiormente incentrato il progetto di tesi. Un modulo di Spark, chiamato Spark SQL, verrà posto in confronto ad Hive nella velocità e nella flessibilità nell’eseguire interrogazioni su database memorizzati sul filesystem
distribuito di Hadoop.
21
Mohyedin, Kermani Ehsan. « Distributed linear programming with Apache Spark ». Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/59990.
Texte intégralRésumé :
For this thesis project, we have implemented Mehrotra's predictor-corrector interior point algorithm on top of Apache Spark for solving large-scale linear programming problems. Our large-scale solver (Spark-LP) is unique because it is open-source, fault-tolerant and can be used on commodity cluster of machines. As a result, Spark-LP provides an opportunity to solve large-scale problems at the lowest possible cost. We have assessed the performance and convergent results of our solver on self-generated, sparse and dense large-scale problems over small to medium-sized clusters, composed of 16 to 64 Amazon's Elastic Computing Cloud r3.xlarge instances.
In conclusions, we have made important suggestions for breaking the current structural limitations so that our solver can be used on heterogeneous clusters containing CPUs and GPUs on JVM environment without the usual numerical
limitations and overheads.Science, Faculty of
Computer Science, Department of
Graduate
22
Capuccini, Marco. « Structure-Based Virtual Screening in Spark ». Thesis, Uppsala universitet, Institutionen för farmaceutisk biovetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-257028.
Texte intégral
23
Fu, Xinye. « Building Evolutionary Clustering Algorithms on Spark ». Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-219608.
Texte intégralRésumé :
Evolutionary clustering (EC) is a kind of clustering algorithm to handle the noise of time-evolved data. It can track the truth drift of clustering across time by considering history. EC tries to make clustering result fit both current data and historical data/model well, so each EC algorithm defines snapshot cost (SC) and temporal cost (TC) to reflect both requests. EC algorithms minimize both SC and TC by different methods, and they have different ability to deal with a different number of cluster, adding/deleting nodes, etc.Until now, there are more than 10 EC algorithms, but no survey about that. Therefore, a survey of EC is written in the thesis. The survey first introduces the application scenario of EC, the definition of EC, and the history of EC algorithms. Then two categories of EC algorithms model-level algorithms and data-level algorithms are introduced oneby-one. What’s more, each algorithm is compared with each other. Finally, performance prediction of algorithms is given. Algorithms which optimize the whole problem (i.e., optimize change parameter or don’t use change parameter to control), accept a change of cluster number perform best in theory.EC algorithm always processes large datasets and includes many iterative data-intensive computations, so they are suitable for implementing on Spark. Until now, there is no implementation of EC algorithm on Spark. Hence, four EC algorithms are implemented on Spark in the project. In the thesis, three aspects of the implementation are introduced. Firstly, algorithms which can parallelize well and have a wide application are selected to be implemented. Secondly, program design details for each algorithm have been described. Finally, implementations are verified by correctness and efficiency experiments.Evolutionär clustering (EC) är en slags klustringsalgoritm för att hantera bruset av tidutvecklad data. Det kan spåra sanningshanteringen av klustring över tiden genom att beakta historien. EC försöker göra klustringsresultatet passar både aktuell data och historisk data / modell, så varje EC-algoritm definierar ögonblicks kostnad (SC) och tidsmässig kostnad (TC) för att reflektera båda förfrågningarna. EC-algoritmer minimerar både SC och TC med olika metoder, och de har olika möjligheter att hantera ett annat antal kluster, lägga till / radera noder etc.Hittills finns det mer än 10 EC-algoritmer, men ingen undersökning om det. Därför skrivs en undersökning av EC i avhandlingen. Undersökningen introducerar först applikationsscenariot för EC, definitionen av EC och historien om EC-algoritmer. Därefter introduceras två kategorier av EC-algoritmer algoritmer på algoritmer och algoritmer på datanivå en för en. Dessutom jämförs varje algoritm med varandra. Slutligen ges resultatprediktion av algoritmer. Algoritmer som optimerar hela problemet (det vill säga optimera förändringsparametern eller inte använda ändringsparametern för kontroll), acceptera en förändring av klusternummer som bäst utför i teorin.EC-algoritmen bearbetar alltid stora dataset och innehåller många iterativa datintensiva beräkningar, så de är lämpliga för implementering på Spark. Hittills finns det ingen implementering av EG-algoritmen på Spark. Därför implementeras fyra EC-algoritmer på Spark i projektet. I avhandlingen införs tre aspekter av genomförandet. För det första är algoritmer som kan parallellisera väl och ha en bred tillämpning valda att implementeras. För det andra har programdesigndetaljer för varje algoritm beskrivits. Slutligen verifieras implementeringarna av korrekthet och effektivitetsexperiment.
24
Hu, Zhengyun. « Turbulence enhancement in spark-ignition engines ». Thesis, Imperial College London, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340890.
Texte intégral
25
Posylkin, Michael. « Mixture preparation in spark-ignition engines ». Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243438.
Texte intégral
26
Wiseman, Marc William. « Spark ignition engine combustion process analysis ». Thesis, University of Nottingham, 1990. http://eprints.nottingham.ac.uk/11131/.
Texte intégralRésumé :
Cylinder pressure analysis is widely used in the experimental investigation of combustion processes within gasoline engines. A pressure record can be processed to reveal detail of charge burning, which is a good indicator of combustion quality. The thesis describes the evaluation of an approximate technique for calculating the mass fraction of the charge that has burnt; a novel approach for determining heat loss to the block; the development of a powerful system for combustion analysis; and the investigation of the correlation between the crank angle location of the 50% mass burnt and minimum timing advance necessary to obtain the maximum engine torque. A detailed examination has been carried out into the uncertainties in the determination of the mass fraction burnt as suggested by Rassweiler and Withrow. A revised procedure has been developed which does not require a priori identification of the combustion end point, and a new approach is suggested to calculate the polytropic indices necessary for the pressure processing. This particular implementation of the analysis is able to identify late burning and misfiring cycles, and then take appropriate steps to ensure their proper analysis. The problems associated with the assumption of uniform pressure; alignment of the pressure changes to the volume changes; pressure sampling rate; clearance volume estimation; and calibrating the acquired pressure to absolute are also evaluated. A novel method is developed to ascertain, directly from the pressure history, the heat loss to the cylinder block. Both experimental and simulated data are used to support the accuracy of the suggested heat loss evaluation, and the sensitivity of the method to its inputs is examined. The conversion of procedures for combustion analysis into a format suitable for undertaking high speed analysis is described. The analysis techniques were implemented so that the engine can be considered to be on-line to the analysis system. The system was entitled Quikburn. This system can process an unlimited number of cycles at a particular running condition, updating the screen every 1.5 seconds. The analysis system has been used to study the potentially beneficial correlation between the location of the 50% mass burnt and MBT. The correlation is examined in detail, and found to be valid except under lean fueling conditions, which is seen to be caused by slow flame initiation. It is suggested that the optimum location of the 50% mass burnt can be used as a reference setting for the ignition timing, and as an indicator of combustion chamber performance. An engine simulation was employed to verify that changes in bum shape account for the small variation seen in the optimum 50% bum locations at different operating conditions of the engine. The bum shape changes also account for the range of optimum locations of the 50% mass burnt encountered in different engines.
27
Abu-Shanab, H. « Spark ignition of methane-air mixtures ». Thesis, University of Leeds, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376990.
Texte intégral
28
NEVES, GUILHERME DE SOUSA. « STOCK FORECASTING FOR ELETRONICS SPARE PARTS ». PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2007. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=11330@1.
Texte intégralRésumé :
Existe consenso entre os pesquisadores de que o modelo de
séries
temporais não é adequado para previsão de peças de
reposição. Entretanto, a
maioria das ferramentas de previsão existentes no mercado
emprega o modelo de
séries temporais. Este trabalho apresenta a distribuição
de Poisson como
alternativa para a previsão de estoque de peças
eletrônicas de reposição. A partir
de noções básicas de gestão de estoques utilizando séries
temporais e dos
conceitos de confiabilidade, disponibilidade e do Processo
de Poisson é proposto
um modelo alternativo. Com o uso de exemplos reais são
apresentados os
resultados da aplicação do modelo proposto e a comparação
com o modelo SAGA,
que utiliza séries temporais. A principal característica
do modelo proposto é o uso
da distribuição de Poisson e a Taxa de Falhas real como
principais parâmetros de
cálculo. A análise dos resultados mostrou que é possível
reduzir os erros de
previsão, o custo de estoque e o número de pedidos não
atendidos, com
conseqüente aumento da Disponibilidade Operacional.There is a consensus that time series model is not appropriate in forecasting replacement parts. However most of market used forecasting tools are time series models. This work presents Poisson distribution as an alternative to forecast replacement parts on electronic equipments. From basic stock management notions, using time series and trust concepts of reliability, availability, and Poisson Process, an alternative model is proposed. Using real examples, the result from proposed model and its comparison to SAGA model, which is based on time series, is presented. The major characteristic of the proposed model is the application of Poisson distribution, and the real faults rate as the main calculus parameters. The analyses results have shown that is possible to reduce forecasting errors, therefore the stock cost, and the reduction of back orders amount, increasing the Operational availability.
29
Siegel, Kathryn I. (Kathryn Iris). « Incremental random forest classifiers in spark ». Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/106105.
Texte intégralRésumé :
Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (page 53).
The random forest is a machine learning algorithm that has gained popularity due to its resistance to noise, good performance, and training efficiency. Random forests are typically constructed using a static dataset; to accommodate new data, random forests are usually regrown. This thesis presents two main strategies for updating random forests incrementally, rather than entirely rebuilding the forests. I implement these two strategies-incrementally growing existing trees and replacing old trees-in Spark Machine Learning(ML), a commonly used library for running ML algorithms in Spark. My implementation draws from existing methods in online learning literature, but includes several novel refinements. I evaluate the two implementations, as well as a variety of hybrid strategies, by recording their error rates and training times on four different datasets. My benchmarks show that the optimal strategy for incremental growth depends on the batch size and the presence of concept drift in a data workload. I find that workloads with large batches should be classified using a strategy that favors tree regrowth, while workloads with small batches should be classified using a strategy that favors incremental growth of existing trees. Overall, the system demonstrates significant efficiency gains when compared to the standard method of regrowing the random forest.
by Kathryn I. Siegel.
M. Eng.
30
Yu, Lucy M. Eng Massachusetts Institute of Technology. « Work-sharing framework for Apache Spark ». Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/113441.
Texte intégralRésumé :
Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (page 39).
Apache Spark is a popular framework for distributed data processing that generalizes the MapReduce model and significantly improves the performance of many use cases. People can use Spark to query enormous data sets faster than before to gain insights for a competitive edge in industry. Often these ad-hoc queries perform similar work, and there is an opportunity to share the work of different queries. This can reduce the total computation time even more. We have developed a Wrapper class which performs such optimizations. In particular, its strategy of lazy evaluation allows duplicate computation to be avoided and multiple related Spark jobs to be executed at the same time, reducing the scheduling overhead. Overall, the system demonstrates significant efficiency gains when compared to default Spark.
by Lucy Yu.
M. Eng.
31
Lind, Simon. « Distributed Ensemble Learning With Apache Spark ». Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-274323.
Texte intégral
32
Brundin, Michelle. « Data Stream Queries to Apache SPARK ». Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-301326.
Texte intégralRésumé :
Many fields have a need to process and analyze data streams in real-time. In industrial applications the data can come from big sensor networks, where the processing of the data streams can be used for performance monitoring and fault detection in real time. Another example is in social media where data stream processing can be used to detect and prevent spam. A data stream management system (DSMS) is a system that can be used to manage and query continuously received data streams. The queries a DSMS executes are called continuous queries (CQs). In contrast to regular database queries they execute continuously until canceled. SCSQ is a DSMS developed at Uppsala university. Apache Spark is a large scale general data processing engine. It has, among other things, a component for data stream processing, Spark Streaming. In this project a system called SCSQ Spark Streaming Interface (SSI) was implemented that allows Spark Streaming applications to be called from CQs in SCSQ. It allows the Spark Streaming applications to receive input streams from SCSQ as well as emitting resulting stream elements back to SCSQ. To demonstrate SSI, two examples are shown where it is used for stream clustering in CQs using the streaming k-means implementation in Spark Streaming.
33
AL, Jorani Salam. « Performance assessment of Apache Spark applications ». Thesis, Linnéuniversitetet, Institutionen för datavetenskap och medieteknik (DM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-80181.
Texte intégralRésumé :
This thesis addresses the challenges of large software and data-intensive systems. We will discuss a Big Data software that consists of quite a bit of Linux configuration, some Scala coding and a set of frameworks that work together to achieve the smooth performance of the system. Moreover, the thesis focuses on the Apache Spark framework and the challenging of measuring the lazy evaluation of the transformation operations of Spark. Investigating the challenges are essential for the performance engineers to increase their ability to study how the system behaves and take decisions in early design iteration. Thus, we made some experiments and measurements to achieve this goal. In addition to that, and after analyzing the result we could create a formula that will be useful for the engineers to predict the performance of the system in production.
34
McIlroy, Colin William. « Muriel Spark and the Romantic ideal ». Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/6439/.
Texte intégralRésumé :
By narrowing the disparate and often contradictory trajectories of Romantic thought into a compressed framework, this thesis seeks to scrutinise the treatment of the Romantic ideal in the fiction of Muriel Spark. A number of recurring themes can be understood to collectively constitute this Romantic ideal. These include Coleridge’s theory of the power of the imagination to coalesce disparities into unity and harmony. The relationship between creativity and psychosis in The Comforters (1957) is considered within a wider discussion on the nature of creativity and the conception of the visionary Romantic artist. This leads to an investigation of the Romantic Movement’s emphasis on interiority and the self, and the influence of John Henry Newman in The Mandelbaum Gate (1965). The resulting discussion treats the concepts of transfiguration and the sublime as they relate to individual subjectivity in The Driver’s Seat (1970). The Romantic fascination with the reinvigoration of myth, legend and oral narrative cultures is examined in relation to The Ballad of Peckham Rye (1960), and the discussion returns to unity, harmony, vision, and the artist in The Finishing School (2004). The investigation of these elements of the Romantic ideal highlights a number of corollary questions. The emphasis on the self prompts the examination of Spark’s engagement with the themes of solipsism, ego, and performance, while Keats’ ‘Negative Capability’ is considered in the attempt to comprehend the other. The methodology will be comparative textual analysis with reference to relevant extant criticism, alongside consideration of literature from anthropology and folklore studies. By illuminating previously overlooked connections with Romanticism and Romantic literary methodologies, this interdisciplinary approach will assist in ascertaining whether Spark’s sustained engagement with these themes is evidence of a complex, multivalent relationship with the Romantic ideal, or whether recent criticism positing her rejection of Romanticism can be upheld.
35
Nates, Roy Jonathan. « Knock damage in spark-ignition engines ». Doctoral thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/11478.
Texte intégralRésumé :
The objectives of this thesis were to identify, explain and quantify the damage caused by knocking combustion in spark-ignition engines. A literature review indicated that, in general, research into knock has focused on the causes and avoidance of knock, rather than on the damage resulting from knock. The few published works concerning the effects of knock were mainly interested in the prevention of one specific form of damage, namely piston erosion. The review highlighted the need to investigate the relationship between knock and the various forms of damage. Using the evidence from knock-damaged engines, the sequence of events leading to failure were reconstructed. The manner in which knock damage manifests itself as surface erosion, piston-ring failure, piston-land cracking, piston blow-by and seizure were examined. From these observations it was deduced that two independent damage paths result from knock. Consequently, the research diverged into two studies, namely: Local pressure-temperature transients in the end-gas zone which cause localised erosion damage; Excessive heat flux associated with knocking combustion which results in global piston and ring problems.
36
Mutzke, Johannes Gerhard. « Abnormal combustion in spark ignition engines ». Thesis, University of Oxford, 2018. http://ora.ox.ac.uk/objects/uuid:0bba0e6c-a989-4791-a80a-8b39fe88f431.
Texte intégralRésumé :
Emissions from internal combustion engines are a major contributor to anthropogenic climate change. In order to decrease the amount of emissions, car manufacturers are investing in increasing the efficiency of spark ignition engines. Means for this include downsizing and turbocharging which come with an exacerbated risk of abnormal and harmful combustion phenomena, notably autoignition, knock and pre-ignition and thus pose a limit to the efficiency of the engines. Abnormal combustion depends on the engine geometry, the operating conditions and the fuel. Industrial standard classification systems are outlined to be insufficient, misleading or non-existent for modern engines and fuels. This thesis aims to improve the understanding of the abnormal combustion phenomena through an experimental project which can be utilised for improved classification systems. The vast majority of the experiments were conducted on a variable compression ratio engine which was fitted with modern control, measurement and data acquisition equipment to resemble an industrially-used test engine. In a first study, methods of finding the ideal engine operating point were investigated. Knock was induced in the engine, and knock indicators and limitations of knock are discussed here. Enhanced humidity was passed into the heated air-inlet stream by means of a custom-built humidifying unit. Results showed that both the power output of the engine and the severity of knock were reduced with increased humidity. This was explained by the exclusion of combustible air. A fuel-vaporization unit allowed for experiments with fully vaporized fuel. It could be shown that this had an adverse effect on knock as the cooling effect of the enthalpy of vaporization was removed. A second study employed a temperature-controlled glow plug to induce surface pre-ignition. A range of analysis techniques were tested and discussed which ranged from flame ionization detection to several in-cylinder pressure based methods. A cycle-by-cycle analysis with a maximum pressure method revealed an unexpected trend of surface pre-ignition tendency in sweeps of stoichiometry and fuels, with slightly weak of stoichiometric mixtures being the most susceptible to pre-ignition. Enhanced humidity had a negligible effect on surface pre-ignition under real world conditions. A third study concerned itself with the analysis of knock-induced heat flux, which is both a major cause for damage to the engine and trigger for surface pre-ignition. A heat flux probe was fitted to the engine and results linking heat flux to knock could be obtained on cycle-by-cycle basis and cycleaveraged basis. A linear trend between heat flux and knock intensity was found.
37
Wakefield, Corey Brion. « Latitudinal and temporal comparisons of the reproductive biology and growth of snapper, Pagrus auratus (Sparidae), in Western Australia ». Thesis, Wakefield, Corey Brion (2006) Latitudinal and temporal comparisons of the reproductive biology and growth of snapper, Pagrus auratus (Sparidae), in Western Australia. PhD thesis, Murdoch University, 2006. https://researchrepository.murdoch.edu.au/id/eprint/382/.
Texte intégralRésumé :
This study focused on obtaining sound quantitative data on the reproductive biology, length and age compositions and growth of the snapper Pagrus auratus in the waters off Carnarvon at ca 25oS and Perth at ca 32oS on the west coast of Australia and at ca 34oS on the south coast of Western Australia. Sampling thus encompassed both sub-tropical and temperate waters and the geographical range within which this species is abundant in Western Australia. The resultant data were used to explore the ways in which the biological characteristics of P. auratus differ with latitude and thus water temperature. An intensive sampling regime for eggs and spawning individuals of P. auratus was conducted in Cockburn Sound, a large marine embayment in the Perth region at ca 32oS. The resultant data were used to elucidate where and when spawning occurs in this large marine embayment and to determine more precisely the factors that influence the timing of spawning. The implications of the results presented in this thesis for the management of P. auratus, a species that has been subjected to very heavy fishing pressure in recent years, are discussed.
The time and duration of spawning of P. auratus in the subtropical waters of Carnarvon differed markedly from those recorded for this sparid in the temperate and cooler waters of the Perth and the south coast regions. Spawning at Carnarvon occurred predominantly in the five months between late autumn (May) and mid spring (September), whereas it took place mainly in the three months between mid spring (October) and early summer (December) in the Perth region. Spawning of P. auratus on the south coast occurred predominantly in October and November in 2003 and 2004 and scarcely at all in 2005. Gonadal recrudescence was thus initiated when water temperatures were close to their maximum but declining in Carnarvon, and close to their minima and rising in the Perth and south coast regions, respectively. The prevalence of fully mature and spawning females in all three regions was greatest in those months when water temperatures lay between 19 and 21oC. Collation of the data in this thesis and those provided in the literature for other populations showed that the spawning period was related to latitude, occurring far earlier in sub-tropical than temperate waters.
The females and males attained maturity at a far smaller total length (L50) in the Carnarvon region, i.e. 378 and 353 mm, respectively, than in the Perth region, 585 and 566 mm, respectively, and also the south coast region, i.e. 600 and 586 mm. The trends exhibited by the age at maturity parallel those for length, with the A50s for the two sexes increasing from ca 4 years in Carnarvon to ca 5.6 years in the Perth region and nearly 7 years in the south coast region. The L50 and A50 at maturity thus both increased with increasing latitude.
Marginal increment analysis demonstrated that, irrespective of the number of opaque zones in the otoliths of P. auratus, a single such opaque zone is laid down each year in these otoliths. Furthermore, the trends exhibited by the monthly marginal increments showed that the opaque zone is laid down predominantly in winter in the subtropical waters of Carnarvon, as opposed to mainly in spring in the temperate waters of the Perth and south coast regions. Thus, the timing of formation of the opaque zone in the otoliths of P. auratus along the Western Australian coast is not related to the trends exhibited by water temperature, but, in both the Carnvarvon and Perth regions, was coincident with the timing of spawning.
The maximum total lengths recorded for females and males in the Carnarvon region, i.e. 864 and 840 mm, respectively, were considerably less than the corresponding values of 1051 and 1056 mm in the Perth region, and 1083 and 1099 mm in the south coast region. Growth in the Perth and south coast regions was greater than in Carnarvon, as is reflected in, for example, the respective lengths of 820, 720 and 610 mm for females at 10 years of age, as determined from the von Bertalanffy growth equations.
The length and age compositions in the Carnarvon and south coast regions were essentially unimodal, whereas those in the Perth region were bimodal. However, the 'mode' in the length-frequency distribution for the south coast region was located well to the right of that in the Carnarvon region, reflecting relatively lower contributions by individuals of the age cohorts of 3 to 6 years. The marked bimodality in the length-frequency distribution for P. auratus in the Perth region was due to the presence of a group of mainly smaller individuals caught outside Cockburn Sound and another of mainly larger individuals that were caught in Cockburn Sound and which formed part of a spawning aggregation in that embayment.
The proportion of fish > 10 years old in the Carnarvon region declined markedly between 2003 and the following two years, presumably reflecting the effect of heavy fishing pressure. This contributed to the decision by fisheries managers to reduced the TAC in those waters after 2003. Age-frequency data demonstrated that annual recruitment success in Cockburn Sound varied greatly, with the 1991, 1992 and 1996 year classes being particularly strong, and recognizing that the relative numbers of the first two year classes did decline progressively between 2002 and 2004. Annual recruitment was particularly variable in the south coast region, with the catches of the 1996 year class dominating the samples.
The relative number of early stage P. auratus eggs in ichthyoplankton samples collected from Cockburn sound on each of four new moons during the spawning seasons of four consecutive years peaked in November in three of those years, i.e. 2001, 2003 and 2004, and in November/December in the remaining year, i.e. 2002. This showed that spawning in this embayment peaked during these months, at which times the mean sea surface temperatures ranged only from 19 to 20oC.
The prevalence of spawning fraction females in sequential samples demonstrated that spawning peaks at the new and, to a lesser extent, full moons. This helps account for the strong positive correlation between spawning fraction and tidal regime, with spawning being greatest when the tidal range is greatest.
Spawning times, back-calculated from the ages of the eggs collected during ichthyoplankton surveys in Cockburn Sound on each of 16 new moons within the spawning periods of four successive years, demonstrated that, in this embayment, P. auratus spawns at night and within the first three hours of the onset of the ebb tide. The distribution of egg concentrations on the 16 new moons showed that, each year, spawning occurred firstly in the north-eastern area of Cockburn Sound and then in the middle and finally north-western areas of this embayment.
In the Perth region, the marine embayments of Cockburn and Warnbro Sound act as nursery areas for P. auratus during the first two years of life. The majority of 2 to 5 year old fish and a large proportion of the 6 year old fish occupy the marine waters outside the embayments. The remaining 6 year old and almost all of the older fish begin to move in September into particularly Cockburn Sound, where they form relatively large spawning aggregations between October and December, before undergoing a massive emigration from this embayment in December/January. The limited returns from fish that were tagged in Cockburn Sound and were subsequently caught outside this embayment indicate that, following spawning, P. auratus does not tend to move in a particular direction.
Pagrus auratus stocks are heavily exploited in offshore, oceanic waters and in embayments, such as Cockburn Sound, where they are particularly susceptible to capture because of the tendency of this species to form spawning aggregations in these same easily accessible locations each year. The data obtained during this thesis show that the L50 at maturity of females and males in temperate waters, i.e. nearly 600 mm, is far greater than the current minimum legal length (MLL) of 410 mm TL. There is thus a need to increase the MLL and/or reduce fishing pressure on immature individuals in open waters. However, the effectiveness of an increase in the MLL may be limited because there is evidence that P. auratus suffers from fishing-induced barotrauma. Closures of specific areas during the spawning season of P. auratus, such as those that have been applied in Cockburn Sound and Shark Bay, are potentially a very effective method for reducing the effects of heavy fishing on spawning individuals.
38
Wakefield, Corey Brion. « Latitudinal and temporal comparisons of the reproductive biology and growth of snapper, Pagrus auratus (Sparidae), in Western Australia ». Wakefield, Corey Brion (2006) Latitudinal and temporal comparisons of the reproductive biology and growth of snapper, Pagrus auratus (Sparidae), in Western Australia. PhD thesis, Murdoch University, 2006. http://researchrepository.murdoch.edu.au/382/.
Texte intégralRésumé :
This study focused on obtaining sound quantitative data on the reproductive biology, length and age compositions and growth of the snapper Pagrus auratus in the waters off Carnarvon at ca 25oS and Perth at ca 32oS on the west coast of Australia and at ca 34oS on the south coast of Western Australia. Sampling thus encompassed both sub-tropical and temperate waters and the geographical range within which this species is abundant in Western Australia. The resultant data were used to explore the ways in which the biological characteristics of P. auratus differ with latitude and thus water temperature. An intensive sampling regime for eggs and spawning individuals of P. auratus was conducted in Cockburn Sound, a large marine embayment in the Perth region at ca 32oS. The resultant data were used to elucidate where and when spawning occurs in this large marine embayment and to determine more precisely the factors that influence the timing of spawning. The implications of the results presented in this thesis for the management of P. auratus, a species that has been subjected to very heavy fishing pressure in recent years, are discussed.
The time and duration of spawning of P. auratus in the subtropical waters of Carnarvon differed markedly from those recorded for this sparid in the temperate and cooler waters of the Perth and the south coast regions. Spawning at Carnarvon occurred predominantly in the five months between late autumn (May) and mid spring (September), whereas it took place mainly in the three months between mid spring (October) and early summer (December) in the Perth region. Spawning of P. auratus on the south coast occurred predominantly in October and November in 2003 and 2004 and scarcely at all in 2005. Gonadal recrudescence was thus initiated when water temperatures were close to their maximum but declining in Carnarvon, and close to their minima and rising in the Perth and south coast regions, respectively. The prevalence of fully mature and spawning females in all three regions was greatest in those months when water temperatures lay between 19 and 21oC. Collation of the data in this thesis and those provided in the literature for other populations showed that the spawning period was related to latitude, occurring far earlier in sub-tropical than temperate waters.
The females and males attained maturity at a far smaller total length (L50) in the Carnarvon region, i.e. 378 and 353 mm, respectively, than in the Perth region, 585 and 566 mm, respectively, and also the south coast region, i.e. 600 and 586 mm. The trends exhibited by the age at maturity parallel those for length, with the A50s for the two sexes increasing from ca 4 years in Carnarvon to ca 5.6 years in the Perth region and nearly 7 years in the south coast region. The L50 and A50 at maturity thus both increased with increasing latitude.
Marginal increment analysis demonstrated that, irrespective of the number of opaque zones in the otoliths of P. auratus, a single such opaque zone is laid down each year in these otoliths. Furthermore, the trends exhibited by the monthly marginal increments showed that the opaque zone is laid down predominantly in winter in the subtropical waters of Carnarvon, as opposed to mainly in spring in the temperate waters of the Perth and south coast regions. Thus, the timing of formation of the opaque zone in the otoliths of P. auratus along the Western Australian coast is not related to the trends exhibited by water temperature, but, in both the Carnvarvon and Perth regions, was coincident with the timing of spawning.
The maximum total lengths recorded for females and males in the Carnarvon region, i.e. 864 and 840 mm, respectively, were considerably less than the corresponding values of 1051 and 1056 mm in the Perth region, and 1083 and 1099 mm in the south coast region. Growth in the Perth and south coast regions was greater than in Carnarvon, as is reflected in, for example, the respective lengths of 820, 720 and 610 mm for females at 10 years of age, as determined from the von Bertalanffy growth equations.
The length and age compositions in the Carnarvon and south coast regions were essentially unimodal, whereas those in the Perth region were bimodal. However, the 'mode' in the length-frequency distribution for the south coast region was located well to the right of that in the Carnarvon region, reflecting relatively lower contributions by individuals of the age cohorts of 3 to 6 years. The marked bimodality in the length-frequency distribution for P. auratus in the Perth region was due to the presence of a group of mainly smaller individuals caught outside Cockburn Sound and another of mainly larger individuals that were caught in Cockburn Sound and which formed part of a spawning aggregation in that embayment.
The proportion of fish > 10 years old in the Carnarvon region declined markedly between 2003 and the following two years, presumably reflecting the effect of heavy fishing pressure. This contributed to the decision by fisheries managers to reduced the TAC in those waters after 2003. Age-frequency data demonstrated that annual recruitment success in Cockburn Sound varied greatly, with the 1991, 1992 and 1996 year classes being particularly strong, and recognizing that the relative numbers of the first two year classes did decline progressively between 2002 and 2004. Annual recruitment was particularly variable in the south coast region, with the catches of the 1996 year class dominating the samples.
The relative number of early stage P. auratus eggs in ichthyoplankton samples collected from Cockburn sound on each of four new moons during the spawning seasons of four consecutive years peaked in November in three of those years, i.e. 2001, 2003 and 2004, and in November/December in the remaining year, i.e. 2002. This showed that spawning in this embayment peaked during these months, at which times the mean sea surface temperatures ranged only from 19 to 20oC.
The prevalence of spawning fraction females in sequential samples demonstrated that spawning peaks at the new and, to a lesser extent, full moons. This helps account for the strong positive correlation between spawning fraction and tidal regime, with spawning being greatest when the tidal range is greatest.
Spawning times, back-calculated from the ages of the eggs collected during ichthyoplankton surveys in Cockburn Sound on each of 16 new moons within the spawning periods of four successive years, demonstrated that, in this embayment, P. auratus spawns at night and within the first three hours of the onset of the ebb tide. The distribution of egg concentrations on the 16 new moons showed that, each year, spawning occurred firstly in the north-eastern area of Cockburn Sound and then in the middle and finally north-western areas of this embayment.
In the Perth region, the marine embayments of Cockburn and Warnbro Sound act as nursery areas for P. auratus during the first two years of life. The majority of 2 to 5 year old fish and a large proportion of the 6 year old fish occupy the marine waters outside the embayments. The remaining 6 year old and almost all of the older fish begin to move in September into particularly Cockburn Sound, where they form relatively large spawning aggregations between October and December, before undergoing a massive emigration from this embayment in December/January. The limited returns from fish that were tagged in Cockburn Sound and were subsequently caught outside this embayment indicate that, following spawning, P. auratus does not tend to move in a particular direction.
Pagrus auratus stocks are heavily exploited in offshore, oceanic waters and in embayments, such as Cockburn Sound, where they are particularly susceptible to capture because of the tendency of this species to form spawning aggregations in these same easily accessible locations each year. The data obtained during this thesis show that the L50 at maturity of females and males in temperate waters, i.e. nearly 600 mm, is far greater than the current minimum legal length (MLL) of 410 mm TL. There is thus a need to increase the MLL and/or reduce fishing pressure on immature individuals in open waters. However, the effectiveness of an increase in the MLL may be limited because there is evidence that P. auratus suffers from fishing-induced barotrauma. Closures of specific areas during the spawning season of P. auratus, such as those that have been applied in Cockburn Sound and Shark Bay, are potentially a very effective method for reducing the effects of heavy fishing on spawning individuals.
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Schild, Ilissa Brooke. « Influence of Spark Energy, Spark Number, and Flow Velocity on Detonation Initiation in a Hydrocarbon-fueled PDE ». Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7527.
Texte intégralRésumé :
Pulsed Detonation Engines (PDEs) have the potential to revolutionize fight by better utilizing the chemical energy content of reactive fuel/air mixtures over conventional combustion processes. Combustion by a super-sonic detonation wave results in a significant increase in pressure in addition to an increase in temperature. In order to harness this pressure increase and achieve a high power density, it is desirable to operate PDEs at high frequency. The process of detonation initiation impacts operating frequency by dictating the length of the chamber and contributing to the overall cycle time. Therefore a key challenge in the development of a practical PDEs is the requirement to rapidly initiate a detonation in hydrocarbon-air mixtures. This thesis evaluates the influence of spark energy and airflow velocity on this challenging initiation process. The influence of spark energy, number of sparks and airflow velocity on Deflagration-to-Detonation Transition (DDT) was studied during cyclic operation of a small-scale PDE at the General Electric Global Research Center. Experiments were conducted in a 50 mm square transitioning to cylindrical channel PDE with optical access operating with stoichiometric ethylene-air mixture. Total spark energy was varied from 250 mJ to 4 J and was distributed between one and four spark plugs located in the same axial location. Initial flame acceleration was imaged using high-speed shadowgraph and was characterized by the time to reach 20 cm from the spark plug. Measurements of detonation wave velocity and emergence time, the time it takes the detonation wave to exit the tube, was measured using dynamic pressure transducers and ionization probes. It was found that the flame front spread was faster at higher spark energies and with more spark locations. Initial flame acceleration was 16% faster for the 4-spark, 4 J case when compared to the baseline 1-spark, 1 J case. When looking at the effect of airflow on the influence of spark energy, it was found that airflow had a larger effect on emergence time at high energies, versus energies less than 1 J. Finally, for a selected case of 0.25 J spark energy and 4 sparks, the velocity of the fuel-air mixture during fill was found to have a varying influence on detonation initiation and emergence time.
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Mohamad, Taib Iskandar. « Development of a spark plug fuel injector for direct injection of natural gas in spark ignition engine ». Thesis, Cranfield University, 2006. http://dspace.lib.cranfield.ac.uk/handle/1826/4436.
Texte intégralRésumé :
The use of methane in spark ignition engines is mainly due to its cleaner emissions and relatively low price. However, when methane replaces gasoline in the externally mixing carburettor or port injection engine, power is reduced and upper speed is limited. These are because the burning velocity of methane is slower than of gasoline, and some air is displaced in the intake manifold in order to compensate the low density methane. The problem can be mitigated when fuel is directly injected into the combustion chamber after the intake valve closes. This results in an increased volumetric efficiency, a higher absolute heating value of mixture and a faster burning rate. The work presented in this thesis aims to develop a conversion system that enables methane to be directly injected into the combustion chamber of a spark ignition engine without modifying the original structure of the engine. The system, named as Spark Plug Fuel Injector (SPFI) combines a fuel injector with a spark plug. A fuel path is drawn along the periphery of the spark plug body to deliver the injected fuel to the combustion chamber. The system was installed and tested on a Ricardo E6 single cylinder engine with compression ratio of 10.5: 1. Cylinder pressures were taken as the main indicator of the engine performance and selected indicated performance were presented. A set of port injected data for the engine running on methane was also taken in order to provide a comparison of performance with SPFI direct injection. Results show that the indicated performance of the SPFI methane direct injection at the tested speed was lower than the optimised methane port injection operation. This was mainly due to the quality of air-fuel mixing, which is a result of spatial and temporal limitation of direct injection operation. Flow visualization using the PLIF method shows that even though sufficient gas jet penetration from SPFI injection nozzle was achieved, the cone angle was very narrow. The conclusion from imaging experiments implies poor mixing, hence the performance suffers drawback. However, with direct injection, volumetric efficiency is increased ands combustion duration is faster. These two factors are desirable for engine performance improvement. SPFI has proven to be a practical and low cost conversion to methane. Even though the performance is lower than port injection, its benefits are significant. As the SPFI design is simple and requires no modification to the original structure of the converted engine.
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Mohamad, Taib Iskandar. « Development of a spark plug fuel injector for direct injection of natural ags in spark ignition engine ». Thesis, Cranfield University, 2006. http://hdl.handle.net/1826/4436.
Texte intégralRésumé :
In the name of God, The Most Gracious, The Most Merciful. By His will, this thesis has
been completed as another episode of knowledge seeking and contribution.
The author wishes to express a greatest gratitude to the academic supervisor for this project,
Dr. Matthew Harrison and Professor Douglas Greenhalgh for their warmth, continuous
guidance and support, priceless knowledge and expertise, and kindly understanding.
Secondly, author's deepest appreciation to Dr. Mark Jermy, the initial supervisor for this
project, for his ideas, understanding, support, availability and generosity for providing
assistance both in author's academic and private life.
To my mother and father whose supplications and encouragements have given me strength
to complete this work. To my family whose support during this course of studies has given
me comfort. To my parents in-law and siblings in-law, thank you for your support.
My dearest gratitude to the beloved wife, Ira for standing by my side and giving me
continuous support throughout this course of study and the hardship of life due to it. Your
sacrifice is priceless. To my children, Balgis, Naufal, Nadiyah and Safiyah, you are my source
of inspirations.
A special thank to Dr. Glenn Sherwood, Tim Lee, Brian Scully, Richard Kennewell, Alan
Hutching, and all others for providing technical supports during the experiment works.
To Andreas, Eudoxios, Anni, Edouard, Fatiha, Alessio, Andy and Adam, I thank you all for
the friendship and helps during my studies.
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Kaul, Brian Christopher. « Addressing nonlinear combustion instabilities in highly dilute spark ignition engine operation ». Diss., Rolla, Mo. : Missouri University of Science and Technology, 2008. http://scholarsmine.mst.edu/thesis/pdf/Kaul_09007dcc804ea67e.pdf.
Texte intégralRésumé :
Thesis (Ph. D.)--Missouri University of Science and Technology, 2008.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed April 28, 2008) Includes bibliographical references (p. 170-176).
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Kapil, Anil. « Cycle-to-cycle variations in spark-ignition engines ». Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28392.
Texte intégralRésumé :
Pressure data measurements have been made in a single-cylinder, spark-ignition engine over 100 consecutive cycles. The engine was operated on natural gas at a wide range of engine speed and equivalence ratios. The effects of spark electrode geometry, combustion chamber geometry, spark gap and throttling have also been examined. From these pressure measurements standard deviations in burning times in mass-fraction-burned values were determined. Because of the existing evidence that the origin of cyclic variations is in the early combustion period, the standard deviations of cyclic variation in time required for a small (almost zero) mass-fraction-burned is estimated by extrapolation. These extrapolated values of standard deviation are compared with the implication of a hypothesis that cyclic variations in combustion in spark-ignition engines originate in the small-scale structure of turbulence (after ignition).
The nature of turbulence structure during combustion is deduced
from existing knowledge of mixture motion within the combustion chamber
of the engine. This research determines the turbulent parameters, such
as turbulence intensity, turbulent length scales and laminar burning
velocity. The standard deviation in burning times in the early stages
of combustion is estimated, within experimental uncertainty, by the
parameter ⋋/4uℓ where ⋋ is the Taylor microscale and uℓ is the laminar
burning velocity of the unburned mixture. This parameter is the
consequence of the Tennekes model of small-scale structure of
turbulence and Chomiak's explanation of the high flame propagation
rate in regions of concentrated vorticity and the assumption that theignition behaves as though it were from a point source.
The general conclusion reached is that the standard deviation in the burning time for small mass-fraction-burned is associated with the early stages of burning-predictable from the knowledge of the Taylor microscale and the laminar burning velocity.Applied Science, Faculty of
Mechanical Engineering, Department of
Graduate
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Torres, Núñez Eva. « Sparc (Osteonectin) : new insight into the function and regulation = Sparc (Osteonectin) : nuevos conocimientos sobre sus funciones y regulación ». Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/133023.
Texte intégralRésumé :
The Extracellular Matrix (ECM) is a complex network secreted by cells that serves as a structural element in tissues and also influences their development and physiology. More specifically, the extracellular matrix helps cells to bind together and regulates several cellular functions such as adhesion, migration, proliferation and differentiation. It is composed of growth factors, proteoglycans, structural proteins and matricellular proteins.
Osteonectin, also named Sparc (Secreted Protein Acidic and Rich in Cysteine) or BM-40 (Membrane Protein-40), is a multifunctional glycoprotein that belongs to the matricellular protein family. This group modulates matrix-cellular interactions and takes part in several cell functions, rather than playing a role in the cell structure. Sparc is known to have high affinity with calcium ions and was first discovered as the major component of ECM in mineral tissues, although it has since been located in many other tissues. Sparc expression is high during early development but remains low in adult life. However, it is expressed in tissues under renewal, tissue repair or tumorigenesis. Since Sparc is able to interact with multiple molecules, many important functions have been attributed to this protein, including counteradhesion, the regulation of cell proliferation and angiogenic activity.
Analysis of the results obtained during this PhD Thesis leads to the following conclusions:
• Sparc is as an important regulator of embryonic haematopoiesis during early development in zebrafish. Specifically, it mediates erythroid progenitor cell development regulating gata1 and βe3globin expression.
• Similar defects in blood phenotypes of sparc and fgfs knockdowns and the capacity to partially rescue the fgf21 blood phenotype places sparc downstream of fgf21 signaling genetic network.
• UV exposure induces an increase in the p53 and sparc expression
• According with the conclusion 3, a possible molecular mechanism induced by sparc after UV-radiation is suggested to be the responsible in part of the increment in developmental abnormalities.
• 5’UTR-intron is key transcriptional regulatory region of sparc gene since gene-construct containing simply this region predominantly displayed GFP expression in notochord, intermediate cell mass, otic vesicle, olfactory epithelium and muscle fibers in injected zebrafish embryos.
• sparc is transcriptionally regulated by DNA methylation through the CpG island detected immediately upstream the 5’ translation start site which is located within the intron sequence.
• Turbot Sparc protein keeps the same protein structure exhibited by all vertebrate Sparc proteins. The predicted turbot Sparc protein sequence shares high similarity to the Sparc proteins of other vertebrates. Phylogenetic analysis also indicated that turbot Sparc clusters together with its vertebrate orthologs. Additionally, we found that the expression pattern of Turbot sparc is comparable to other teleost species. Therefore, these results suggest a strong evolutionary pressure to conserve this protein and indicate that there should be an evident conservation of function.
• sparc mRNA expression showed a dynamic stage-specific expression during post-embryonic turbot development with high levels at metamorphic climax, indicating that it might be necessary for turbot metamorphosis.Osteonectina, también llamada Sparc o BM-40, es una glicoproteína multifuncional que pertenece a la familia de las proteínas matricelulares de la matriz extracelular. Este grupo modula las interacciones entre la matriz y las células e interviene en múltiples funciones más que jugar un papel en la estructura celular. Se sabe que Sparc tiene una alta afinidad por los iones calcio y fue descubierta por primera vez como el componente mayoritario de la matriz extracelular de tejidos mineralizados. Más tarde, se localizó Sparc en muchos otros tejidos. La expresión de Sparc es alta durante el desarrollo temprano y disminuye durante la edad adulta. Sin embargo, su expresión aumenta en tejidos que requieren cierto grado de renovación, reparación o en tumorigénesis. Debido a que Sparc es capaz de interactuar con múltiples moléculas, se le han atribuido importantes funciones como antiadhesión, regulación del ciclo celular y actividad angiogénica. Debido al poco conocimiento respecto a la regulación de Sparc y los papeles contradictorios en diferentes tejidos, el objetivo principal de esta tesis es contribuir a un mayor entendimiento de este gen en peces teleósteos. En esta tesis demostramos: 1. Sparc es un regulador importante en hematopoyesis embriogénica durante el desarrollo temprano del pez cebra. 2. Localizamos sparc corriente abajo de fgf21 en esta cascada de regulación. 3. La radiación ultravioleta es capaz de inducir un incremento en la expresión de p53 y Sparc. 4. Dado que sparc está altamente expresada en embriones expuestos a radiación ultravioleta, este gen puede estar implicado en el incremento de malformaciones durante el desarrollo. Así, se sugiere que posiblemente sparc sea capa de inducir un mecanismo molecular en respuesta a la exposición de UV. 5. El intrón localizado entre las dos regiones 5’UTR es clave para regulación transcripcional de sparc ya que el vector conteniendo únicamente esta secuencia asociada a GFP es capaz de expresar fluorescencia en notocorda, ICM, vesícula ótica, bulbo olfatorio y fibras musculares, lugares donde se sabe que sparc está presente tanto en pez cebra como en otras especies de teleósteos. 6. Sparc está regulada a nivel de la transcripción por metilación del ADN. Concretamente, la isla CpG detectada en el intrón es susceptible a procesos de metilación. 7. Tanto la secuencia aminoacídica de Sparc como los lugares de expresión en larvas de rodaballo (Scophthalmus maximus) están altamente conservados cuando se comparan con las secuencias existentes en otras especies. 8. Sparc tiene un papel durante la metamorfosis de rodaballo por su alta expresión en etapas premetamórficas.
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Almesjö, Fredrik. « Regression modeling of cyclotron spare parts consumption ». Thesis, Uppsala universitet, Matematisk statistik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-179484.
Texte intégral
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Persson, Robin, et Andreas Ahlin. « Hemautomation : Spara energi genom att automatisera hemmet ». Thesis, Karlstads universitet, Institutionen för matematik och datavetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-36284.
Texte intégralRésumé :
In today's society there is a significant focus on energy efficiency. Despite this, people leave lamps, televisions and computer screens etc. powered on unnecessarily. The goal of this project is to build a simple prototype for home automation where a user, via an application on a mobile phone, can switch on and off the power of an electrical products in the home and as well as being able to check whether such products are switched on or off. The prototype will also collect data on power consumption for these electrical products. This thesis describes the development of the prototype and addresses the choices made during the project. The project resulted in a prototype which after tests showed that there is potential to save energy by using home automation.Sammanfattning I dagens samhälle är det stor fokus på energieffektivisering. Trots detta låter många människor lampor, tv-apparater och datorskärmar med mera, stå påslagna helt i onödan. Målet med detta projekt är att bygga en enkel prototyp för hemautomation där en användare via en applikation på en mobiltelefon kan slå på och av strömmen för elektriska produkter i hemmet, samt se om dessa produkter är på eller avslagna. Prototypen ska också samla in data om strömförbrukningen för dessa elektriska produkter. Denna uppsats beskriver utvecklingen av prototypen och tar upp de val som har gjorts under projektets gång. Projektet resulterade i en prototyp som efter test visade att det finns potential att använda hemautomation till att spara ström.
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Safari, Arash. « Matrix Multiplications on Apache Spark through GPUs ». Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-210891.
Texte intégralRésumé :
In this report, we consider the distribution of large scale matrix multiplications across a group of systems through Apache Spark, where each individual system utilizes Graphical Processor Units (GPUs) in order to perform the matrix multiplication. The purpose of this thesis is to research whether the GPU's advantage in performing parallel work can be applied to a distributed environment, and whether it scales noticeably better than a CPU implementation in a distributed environment. This question was resolved by benchmarking the different implementations at their peak. Based on these benchmarks, it was concluded that GPUs indeed do perform better as long as single precision support is available in the distributed environment. When single precision operations are not supported, GPUs perform much worse due to the low double precision performance of most GPU devices.I denna rapport betraktar vi fördelningen av storskaliga matrismultiplikationeröver ett Apache Spark kluster, där varje system i klustret delegerar beräkningarnatill grafiska processorenheter (GPU). Syftet med denna avhandling är attundersöka huruvida GPU:s fördel vid parallellt arbete kan tillämpas på en distribuerad miljö, och om det skalar märkbart bättre än en CPU-implementationi en distribuerad miljö. Detta gjordes genom att testa de olika implementationerna i en miljö däroptimal prestanda kunde förväntas. Baserat på resultat ifrån dessa tester drogsslutsatsen att GPU-enheter preseterar bättre än CPU-enheter så länge ramverkethar stöd för single precision beräkningar. När detta inte är fallet så presterar deflesta GPU-enheterna betydligt sämre på grund av deras låga double-precisionprestanda.
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Aycock, John Daniel. « Practical Earley parsing and the SPARK toolkit ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ58556.pdf.
Texte intégral
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Sleightholme-Albanis, G. R. « Measurements of spark-ignition engine fuelling variations ». Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241120.
Texte intégral
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Sorrell, A. J. « Spark ignition engine performance during warm-up ». Thesis, Brunel University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234957.
Texte intégral