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Wyszukujesz frazę "Rodriguez, C. G." wg kryterium: Autor


Tytuł:
Numerical model to study the combustion process and emissions in the Wartsila 6L 46 four-stroke marine engine
Autorzy:
Lamas, M. I.
Rodriguez, C. G.
Powiązania:
https://bibliotekanauki.pl/articles/259746.pdf
Data publikacji:
2013
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
marine engine
emissions
combustion
CFD Computational Fluid Dynamics
Opis:
The aim of the present paper is to develop a computational fluid dynamics (CFD) analysis to study the combustion process in a four-stroke marine diesel engine, the Wärtsilä 6L 46. The motivation comes from the importance of emissions from marine engines in the global emissions, particularly for nitrogen oxides (NOx) and sulfur oxides (SOx). The pressure and temperature fields were obtained, as well as the exhaust gas composition. In order to validate this work, the numerical results were satisfactory compared with experimental ones, which indicates that this model is accurate enough to reproduce the fluid pattern inside the cylinder during the combustion process. Accordingly, the aim of future works is to use this numerical procedure to optimize the performance and reduce the emissions of the new marine engine designs.
Źródło:
Polish Maritime Research; 2013, 2; 61-66
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical model to study the valve overlap period in the Wärtsilä 6L 46 four-stroke marine engine
Autorzy:
Lamas, M. I.
Rodríguez, C. G.
Rebollido, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/259055.pdf
Data publikacji:
2012
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
four-stroke engine
computational fluid dynamics (CFD)
marine engine
Opis:
In this paper, a CFD (Computational Fluid Dynamics) analysis was carried out to study the Wärtsilä 6L 46 medium-speed, four-stroke marine engine. For the purpose, the commercial software ANSYS Fluent 6.3 was employed. The aim is to analyze the scavenging of gases, especially during the valve overlap period. Particularly, the pressure, velocity and mass fraction fields were numerically obtained. In order to validate the CFD results, the in-cylinder pressure was successfully compared to experimental measurements for the exhaust, intake and compression strokes of the cylinder operation. This model can be used in future works to improve the performance of these engines because the information provided is very useful to identify regions in which the pressure, velocity or distribution of gases are inadequate. Besides, to compute the quantity of burnt gases which remain inside the cylinder, fresh charge which is expelled through the exhaust valves and study the influence of parameters such as the exhaust and intake pressures, engine speed, cam profile design, etc.
Źródło:
Polish Maritime Research; 2012, 1; 31-37
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical model of so2 scrubbing with seawater applied to marine engines
Autorzy:
Lamas, M. I.
Rodríguez, C. G.
Rodríguez, J. D.
Telmo, J.
Powiązania:
https://bibliotekanauki.pl/articles/258856.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
sulphur dioxide
SO2
scrubbers
CFD
Opis:
The present paper proposes a CFD model to study sulphur dioxide (SO2) absorption in seawater. The focus is on the treatment of marine diesel engine exhaust gas. Both seawater and distilled water were compared to analyze the effect of seawater alkalinity. The results indicate that seawater is more appropriate than distilled water due to its alkalinity, obtaining almost 100% cleaning efficiency for the conditions analyzed. This SO2 reduction meets the limits of SOx emission control areas (SECA) when operating on heavy fuel oil. These numerical simulations were satisfactory validated with experimental tests. Such data are essential in designing seawater scrubbers and judging the operating cost of seawater scrubbing compared to alternative fuels.
Źródło:
Polish Maritime Research; 2016, 2; 42-47
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the pre-injection system of a marine diesel engine through multiple-criteria decision-making and artificial neural networks
Autorzy:
Rodriguez, C. G.
Lamas, M. I.
Rodriguez, J. D.
Abbas, A.
Powiązania:
https://bibliotekanauki.pl/articles/2033205.pdf
Data publikacji:
2021
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
marine engine
emissions
consumption
artificial neural networks
multi-criteria decision making
computational fluid dynamics
Opis:
The present work proposes several pre-injection patterns to reduce nitrogen oxides in the Wartsila 6L 46 marine engine. A numerical model was carried out to characterise the emissions and consumption of the engine. Several pre-injection quantities, durations, and starting instants were analysed. It was found that oxides of nitrogen can be noticeably reduced but at the expense of increasing consumption as well as other emissions such as carbon monoxide and hydrocarbons. According to this, a multiple-criteria decision-making (MCDM) model was established to select the most appropriate parameters. Besides, an artificial neural network (ANN) was developed to complement the results and analyse a huge quantity of alternatives. This hybrid MCDM-ANN methodology proposed in the present work constitutes a useful tool to design new marine engines.
Źródło:
Polish Maritime Research; 2021, 4; 88-96
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of emissions from marine engines using alternative fuels
Autorzy:
Lamas, M. I.
Rodriguez, C. G.
Telmo, J.
Rodriguez, J. D.
Powiązania:
https://bibliotekanauki.pl/articles/260425.pdf
Data publikacji:
2015
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
fuel
natural gas
hydrogen
marine engine
emissions
Opis:
The current restrictions on emissions from marine engines, particularly sulphur oxides (SOx ), nitrogen oxides (NOx ) and carbon dioxide (CO2 ), are compelling the shipping industry to a change of tendency. In the recent years, many primary and secondary reduction techniques have been proposed and employed in marine engines. Nevertheless, the increasingly restrictive legislation makes it very difficult to continue developing efficient reduction procedures at competitive prices. According to this, the paper presents the possibility to employ alternative fuels. A numerical model was developed to analyze the combustion process and emissions using oil fuel, natural gas and hydrogen. A commercial marine engine was studied, the Wartsila 6L 46. It was found, that hydrogen is the cleanest fuel regarding CO2 , hydrocarbons (HC) and carbon monoxide (CO). Nevertheless, it is very expensive for marine applications. Natural gas is cheaper and cleaner than fuel oil regarding CO2 and CO emissions. Still, natural gas emits more NOx and HC than oil fuel. SOx depends basically on the sulphur content of each particular fuel.
Źródło:
Polish Maritime Research; 2015, 4; 48-52
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Three-dimensional cfd analysis to study the thrust and efficiency of a biologicallyinspired marine propulsor
Autorzy:
Lamas, M. I.
Rodríguez, J. D.
Rodríguez, C. G.
González, P. B.
Powiązania:
https://bibliotekanauki.pl/articles/259319.pdf
Data publikacji:
2011
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
fish swimming
marine propulsion
undulating fin
biomimetic
computational fluid dynamics (CFD)
CFD
Opis:
Aquatic animals, which are the result of many millions of years of evolutionary optimization, are very quick, efficient, robust, and versatile. Accordingly, biologically-inspired mechanisms which emulate the movement of animals have recently become very popular. For the efficient design of a propulsion system it is very important to analyze the fluid flow in detail. CFD (Computational Fluid Dynamics) has become a powerful technique to understand the phenomena because it gives extensive information about the fluid flow characteristics. In the present work, a propulsion system consisting of an undulating fin which emulates the fish swimming was built. In order to optimize the mechanism, several undulating configurations were studied using a 3D turbulent CFD model. The thrust, drag, efficiency and hydrodynamic characteristics were analyzed. Furthermore, it was shown that the efficiency and thrust depend strongly on the oscillation frequency, amplitude and wavelength. In order to validate this CFD model, the numerically obtained thrust was successfully compared with experimental results from the laboratory mechanism.
Źródło:
Polish Maritime Research; 2011, 1; 10-16
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Eocene and not Cretaceous origin of spider wasps: fossil evidence from amber
Autorzy:
Rodriguez, J.
Waichert, C.
Von Dohlen, C.D.
Poinar,Jr., G.
Pitts, J.P.
Powiązania:
https://bibliotekanauki.pl/articles/20131.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Eocene
Cretaceous
spider wasp
pompilid wasp zob.spider wasp
fossil evidence
amber
Hymenoptera
Pompilidae
Opis:
Spider wasps had long been proposed to originate in the Late Cretaceous based on the Burmese amber fossil Bryopompilus interfector. We performed a morphological examination of this fossil and determined that it does not belong to Pompilidae or any other described hymenopteran family. Instead, we place it in the new family Bryopompilidae. The oldest verifiable member of the Pompilidae is from Baltic amber, which suggests that the crown group of the family probably originated in the Eocene, not in the Late Cretaceous as previously proposed. The origin of spider wasps appears to be correlated with an increase in spider familial diversity in the Cenozoic. We also add two genera to the extinct pompilid fauna: Tainopompilus Rodriguez and Pitts gen. nov. and Paleogenia Waichert and Pitts gen. nov., and describe three new species of fossil spider wasps: Anoplius planeta Rodriguez and Pitts sp. nov., from Dominican amber (Burdigalian to Langhian); Paleogenia wahisi Waichert and Pitts sp. nov., from Baltic amber (Lutetian to Priabonian); and Tainopompilus argentum Rodriguez and Pitts sp. nov., from Dominican amber (Chattian to Langhian).
Źródło:
Acta Palaeontologica Polonica; 2016, 61, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New association between Amblyomma parvitarsum (Acari: Ixodidae) and the endemic lizard Liolaemus eleodori (Iguania: Liolaemidae) in Argentina
Autorzy:
Castillo, G.N.
Acosta, J.C.
Rodríguez-Munoz, M.
Martínez, T.
Gonzalez-Rivas, C.
Nava, S.
Powiązania:
https://bibliotekanauki.pl/articles/5570.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Parazytologiczne
Źródło:
Annals of Parasitology; 2019, 65, 1
0043-5163
Pojawia się w:
Annals of Parasitology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on health risk factors as a basis to implement programs that promote a nutritional culture in students of the la Sabana University
Autorzy:
Rodriguez, S.
Martinez, M.
Segnini, F.
Cajiao, V.
Aivasovsky, I.
Celis, L.G.
Ayala, J.
Rozo, C.
Russi, A.
Girata, V.
Almonacid, C.C.
Powiązania:
https://bibliotekanauki.pl/articles/2087202.pdf
Data publikacji:
2021
Wydawca:
Narodowy Instytut Zdrowia Publicznego. Państwowy Zakład Higieny
Tematy:
health promotion
disease prevention
obesity
non-communicable diseases
healthy lifestyle
Opis:
Background. Nowadays the importance of lifestyles in the prevention of type 2 diabetes and the metabolic syndrome has been largely accertained. Objective. The purpose of our work is to implement programs that promote a nutritional culture in adolescents and young adults of the La Sabana University. Methods. The methodology entailed, after the corresponding informed consent, taking measures of the triceps and supraescapular skinfolds, waist circumference, body mass index (BMI), lean mass, and fat mass. Fasting blood samples were also taken to quantify cholesterol, triglycerides, high density lipoprotein (HDL) and low density lipoprotein (LDL). Results. The results obtained show that of the 165 students, 10.3% were underweight, 13.93% were overweight and 0.6% were obese. With regards to gender, 4.8% of the men and 9% of the women were overweight, 3% of the men and 7.2% of the women were underweight, and 0.6% of the women were obese. The blood chemistry showed that 30% had hypercholesterolemia, 18% hypertriglyceridemia, 17% reported low HDL levels and 67% reported high LDL levels. Of all the cases studied, 40% are at risk of a metabolic syndrome. 60% claimed not to practice any physical activity - especially women who reported 44.70%. Conclusions. These findings have allowed us at the institution to implement a culture of healthy habits. The have also allowed us to identify students with risk factors for type 2 diabetes and metabolic syndrome. This is why the cardio- metabolic monitoring and control based on healthy eating and physical activity are important.
Źródło:
Roczniki Państwowego Zakładu Higieny; 2021, 72, 1; 89-94
0035-7715
Pojawia się w:
Roczniki Państwowego Zakładu Higieny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical characteristics and yield of maize grain in rainfed conditions of high valleys of Mexico
Właściwości fizyczne i plony ziarna kukurydzy w warunkach deszczowego zasilania w wodę w wysokich dolinach Meksyku
Autorzy:
Benitez-Rodriguez, M.G.
Zepeda-Bautista, R.
Hernandez-Aguilar, C.
Virgen-Vergas, J.
Rojas-Martinez, I.
Dominguez-Pacheco, A.
Powiązania:
https://bibliotekanauki.pl/articles/35536.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Opis:
In the High Valleys of Mexico maize is produced with varied yield and quality which sometimes do not meet the parameters established by maize flour milling and nixtamalization industry for making tortilla. Therefore, an evaluation of the yields and quality of the grain of maize hybrids (Zea mays L.) and their relationship with the environment was performed. During the spring-summer cycle 2012, the hybrids HP-1, H-52, H-68, HP-2, H-70, Buho, HP-3, H-57E, H-64, Prospecto-1, H-72 and H-66 were evaluated in Texoloc and Benito Juárez (2240 and 2530 masl), Tlaxcala, Mexico in a design of completely randomised blocks with three replications. Grain yield (GY), thousand grain weight (TGW), hectolitric weight (HW), width (WG), length (LG) and thickness (TG) of grains were measured. The results showed highly significant differences (p = 0.01) between locations, hybrids and the interaction locality x hybrids for physical parameters. Among the localities, Texoloc had 86.59% and 24.32% higher GY and TGW compared to Benito Juarez, respectively, while the HW was slightly lower (73.68 kg hL-1). Average yields of the hybrids were 7.7 t ha-1; HP-2, HP-3, H-57E and H-66 hybrids had yields of more than 8 t ha-1 and the lowest yield was noted for H-70. The hybrids had an average HW of 74.30 kg hL-1; HP-1, H-68, H-70, Buho, HP-3 and H-72 had values > 74 kg hL-1, complying with the provisions of the quality standard NMX-FF034/1-SCFI- 2002 for maize destined for the nixtamalization process. The variation in agroclimatic conditions between the localities affected the yield and physical quality of maize grain.
W Wysokich Dolinach Meksyku produkowana jest kukurydza o zróżnicowanej jakości i poziomie plonowania, która nie zawsze spełnia wymagania przemysłu młynarskiego i nixtamalizacji mąki kukurydzianej do produkcji tortilli. Z tego powodu przeprowadzono badania, mające na celu ocenę plonowania i jakości ziarna hybryd kukurydzy (Zea mays L.) oraz ich zależności od warunków środowiskowych. W sezonie wiosenno-letnim roku 2012 przeprowadzono badania na hybrydach HP-1, H-52, H-68, HP-2, H-70, Buho, HP-3, H-57E, H-64, Prospecto-1, H-72 oraz H-66 w Texoloc i Benito Juárez (2240 i 2530 m n.p.m.), Tlaxcala w Meksyku. Badania przeprowadzono w systemie bloków losowych, w trzech powtórzeniach, dokonując pomiarów plonu ziarna, masy tysiąca ziaren, masy hektolitra ziarna oraz szerokości, długości i grubości ziarna. Stwierdzono istotne różnice (p = 0,01) pomiędzy lokalizacjami, hybrydami oraz interakcjami lokalizacja- hybryda w zakresie parametrów fizycznych ziarna. Wartości plonu i masy 1000 ziaren w Texoloc były wyższe odpowiednio o 86,59% i 24,32% w porównaniu do wartości otrzymanych w Benito Juarez, podczas gdy wartość masa hektolitra była nieznaczenie niższa (73,68 kg·hL-1). Średni plon ziarna hybryd wyniósł 7,7 t·ha-1; plony hybryd HP-2, HP-3, H-57E i H-66 były powyżej 8 t·ha-1, a najniższy plon uzyskano dla hybrydy H-70. Średnia wartość masy hektolitra dla hybryd kukurydzy wyniosła 74,30 kg·hL-1; dla hybryd HP-1, H-68, H-70, Buho, HP-3 i H-72 były > 74 kg·hL-1, spełniając wymagania jakościowe normy NMX-FF034/1-SCFI-2002 dla kukurydzy przeznaczonej do procesu nixtamalizacji. Zróżnicowanie warunków agroklimatycznych pomiędzy badanymi lokalizacjami miało wpływ na plonowanie i charakterystyki fizyczne ziarna kukurydzy.
Źródło:
Acta Agrophysica; 2014, 21, 4
1234-4125
Pojawia się w:
Acta Agrophysica
Dostawca treści:
Biblioteka Nauki
Artykuł

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