Готові списки джерел за темами / Cetacea, Fossil

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Добірка наукової літератури з теми "Cetacea, Fossil"

Автор: Grafiati
Опубліковано: 4 червня 2021
Оновлено: 17 лютого 2022

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Статті в журналах з теми "Cetacea, Fossil"

1

O'Leary, Maureen A., and Mark D. Uhen. "The time of origin of whales and the role of behavioral changes in the terrestrial-aquatic transition." Paleobiology 25, no. 4 (1999): 534–56. http://dx.doi.org/10.1017/s0094837300020376.

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Addition of the recently discovered fossil Nalacetus to a phylogenetic analysis of basicranial, cranial, dental, postcranial, and soft morphological characters reveals that it is the most basal cetacean, and that mesonychians form the monophyletic sister group to Cetacea. The molars of Nalacetus elucidate transformations in dental morphology that occurred early in the cetacean radiation and clarify certain derived differences in molar cusp position between cetaceans and the extinct clade, Mesonychia, hypothesized to be their sister taxon. Nalacetus and other archaic cetaceans share derived vertically elongate shearing facets on the lower molars. Applying the Extant Phylogenetic Bracket, we advance the hypothesis that these facets are an osteological correlate of aquatic predation. Our functional interpretation of this character and its distribution within Cetacea indicates that a behavioral change in tooth use characterized the origin of the clade. Comparison of the transformation of this dental character with that of the cetacean pelvis indicates that a change in tooth use (feeding behavior) occurred before loss of the ability to engage in terrestrial locomotion.The most parsimonious phylogenetic hypothesis presented here has a significant fit with the stratigraphic record as determined by the Manhattan Stratigraphic Measure, which is corroborated by retention indices of stratigraphic data. Ghost lineages necessitated by the phylogenetic hypothesis extend the stratigraphic range of Cetacea into the middle Paleocene (Torrejonian), ten million years earlier than the oldest cetacean fossil currently known. Primitive features of Nalacetus, the large number of synapomorphies diagnosing Cetacea, and the implied ghost lineage suggest that the early cetacean radiation was much more extensive than has been previously recognized.
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2

Loch, Carolina, Jules A. Kieser, and R. Ewan Fordyce. "Enamel Ultrastructure in Fossil Cetaceans (Cetacea: Archaeoceti and Odontoceti)." PLOS ONE 10, no. 1 (January 28, 2015): e0116557. http://dx.doi.org/10.1371/journal.pone.0116557.

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3

Bianucci, Giovanni, Christian de Muizon, Mario Urbina, and Olivier Lambert. "Extensive Diversity and Disparity of the Early Miocene Platanistoids (Cetacea, Odontoceti) in the Southeastern Pacific (Chilcatay Formation, Peru)." Life 10, no. 3 (March 18, 2020): 27. http://dx.doi.org/10.3390/life10030027.

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Several aspects of the fascinating evolutionary history of toothed and baleen whales (Cetacea) are still to be clarified due to the fragmentation and discontinuity (in space and time) of the fossil record. Here we open a window on the past, describing a part of the extraordinary cetacean fossil assemblage deposited in a restricted interval of time (19–18 Ma) in the Chilcatay Formation (Peru). All the fossils here examined belong to the Platanistoidea clade as here redefined, a toothed whale group nowadays represented only by the Asian river dolphin Platanista gangetica. Two new genera and species, the hyper-longirostrine Ensidelphis riveroi and the squalodelphinid Furcacetus flexirostrum, are described together with new material referred to the squalodelphinid Notocetus vanbenedeni and fragmentary remains showing affinities with the platanistid Araeodelphis. Our cladistic analysis defines the new clade Platanidelphidi, sister-group to Allodelphinidae and including E. riveroi and the clade Squalodelphinidae + Platanistidae. The fossils here examined further confirm the high diversity and disparity of platanistoids during the early Miocene. Finally, morphofunctional considerations on the entire platanistoid assemblage of the Chilcatay Formation suggest a high trophic partitioning of this peculiar cetacean paleocommunity.
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4

Aguirre-Fernández, Gabriel, Jorge D. Carrillo-Briceño, Rodolfo Sánchez, Eli Amson, and Marcelo R. Sánchez-Villagra. "Fossil Cetaceans (Mammalia, Cetacea) from the Neogene of Colombia and Venezuela." Journal of Mammalian Evolution 24, no. 1 (August 31, 2016): 71–90. http://dx.doi.org/10.1007/s10914-016-9353-x.

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5

RAVIKANT, VADLAMANI, and S. BAJPAI. "Strontium isotope evidence for the age of Eocene fossil whales of Kutch, western India." Geological Magazine 147, no. 3 (February 8, 2010): 473–77. http://dx.doi.org/10.1017/s0016756810000099.

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AbstractThe Indian subcontinent is widely considered to be the birthplace of whales (Cetacea), and the middle Eocene Harudi Formation of Kutch has long been known to be a major source of early whales. The Kutch cetaceans are of critical importance in understanding the evolutionary transition of whales from land to sea. Strontium isotope analysis of marine biogenic carbonates from the Harudi Formation was conducted to obtain a numerical age of the whale-bearing strata. Although the measured 87Sr/86Sr ratios (0.707742 to 0.707764) correspond to two distinct age clusters of 46–47.5 Ma or 41–42.5 Ma, we prefer the latter, late Lutetian, age cluster.
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6

Etienne, Rampal S., Bart Haegeman, Tanja Stadler, Tracy Aze, Paul N. Pearson, Andy Purvis, and Albert B. Phillimore. "Diversity-dependence brings molecular phylogenies closer to agreement with the fossil record." Proceedings of the Royal Society B: Biological Sciences 279, no. 1732 (October 12, 2011): 1300–1309. http://dx.doi.org/10.1098/rspb.2011.1439.

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The branching times of molecular phylogenies allow us to infer speciation and extinction dynamics even when fossils are absent. Troublingly, phylogenetic approaches usually return estimates of zero extinction, conflicting with fossil evidence. Phylogenies and fossils do agree, however, that there are often limits to diversity. Here, we present a general approach to evaluate the likelihood of a phylogeny under a model that accommodates diversity-dependence and extinction. We find, by likelihood maximization, that extinction is estimated most precisely if the rate of increase in the number of lineages in the phylogeny saturates towards the present or first decreases and then increases. We demonstrate the utility and limits of our approach by applying it to the phylogenies for two cases where a fossil record exists (Cetacea and Cenozoic macroperforate planktonic foraminifera) and to three radiations lacking fossil evidence ( Dendroica , Plethodon and Heliconius ). We propose that the diversity-dependence model with extinction be used as the standard model for macro-evolutionary dynamics because of its biological realism and flexibility.
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7

Fitzgerald, Erich M. G. "A review of the Tertiary fossil Cetacea (Mammalia) localities in Australia." Memoirs of Museum Victoria 61, no. 2 (2004): 183–208. http://dx.doi.org/10.24199/j.mmv.2004.61.12.

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8

O'Leary, Maureen A., Biren A. Patel, and Mark N. Coleman. "Endocranial petrosal anatomy of Bothriogenys (Mammalia, Artiodactyla, Anthracotheriidae), and petrosal volume and density comparisons among aquatic and terrestrial artiodactyls and outgroups." Journal of Paleontology 86, no. 1 (January 2012): 44–50. http://dx.doi.org/10.1666/10-091.1.

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We provide the first detailed endocranial description of the petrosal bone of the ear region of the anthracotheriid artiodactyl Bothriogenys, based on two new specimens from the early Oligocene of the Jebel Qatrani Formation, Fayum, Egypt. The new fossils have petrosals with a hyperinflated (pachyostotic) tegmen tympani (the roof over the middle ear), resembling the condition in certain cetancodontans such as hippopotamids and basal cetaceamorphans (fossil stem taxa to extant Cetacea).The morphology of the petrosal, particularly its relative size and density, has been considered an important indicator of the ability of a marine mammal to localize sound transmitted in water, yet petrosal size (pachyostosis) and density (osteosclerosis) have not previously been quantified independent of each other. We examine the new fossils in the context of a preliminary CT-based study of petrosal density (extant taxa only) and petrosal volume (extant and extinct taxa) in a sample of artiodactyls and outgroups. In our extant comparative sample, the petrosals of cetaceans are both dense and voluminous as has been previously stated. We find, however, that the tegmen tympani is relatively voluminous (pachyostotic) without being particularly dense (osteosclerotic) in Hippopotamus amphibius, an extant taxon that has been documented to show some aquatic hearing behaviors, albeit less derived ones than those seen in cetaceans. A voluminous tegmen tympani, which is present in Bothriogenys, may have specific implications for behavior that are distinct from increases in petrosal density.
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9

Buchholtz, Emily A. "Vertebral osteology and swimming style in living and fossil whales (Order: Cetacea)." Journal of Zoology 253, no. 2 (February 2001): 175–90. http://dx.doi.org/10.1017/s0952836901000164.

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10

Tsai, Cheng-Hsiu, and Robert W. Boessenecker. "An Early Pleistocene gray whale (Cetacea: Eschrichtiidae) from the Rio Dell Formation of northern California." Journal of Paleontology 89, no. 1 (January 2015): 103–9. http://dx.doi.org/10.1017/jpa.2014.9.

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AbstractThe earliest fossil gray whale (Eschrichtius) from the eastern North Pacific is reported from the Lower Pleistocene Rio Dell Formation of Humboldt County, Northern California. This specimen, a tympanic bulla and posterior process, is identical in morphology to extantEschrichtius robustusand differs from PlioceneEschrichtiussp. from the western North Pacific (Japan). Thus, it suggests that the modern bulla morphology of the gray whale had been acquired by the Early Pleistocene. The absence of fossilEschrichtiusin the Pliocene of the eastern North Pacific may indicate that the extant gray whale lineage originated in the western North Pacific during the Pliocene before invading the eastern North Pacific during the Early Pleistocene. Further discoveries of Plio-Pleistocene gray whale fossils will help test this hypothesis and properly interpret the evolutionary history of eschrichtiid clade.
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Дисертації з теми "Cetacea, Fossil"

1

Jourdain, de Muizon Christian. "Les Odontocètes (Cetacea, Mammalia) du néogène de la formation Pisco (Pérou) phylogénie et taxonomie des odontocètes fossiles et actuels /." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37606294j.

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2

Muizon, Christian de. "Les odontocetes ( cetacea, mammalia) du neogene de la formation pisco (perou) : phylogenie et taxonomie des odontocetes fossiles et actuels." Paris 7, 1987. http://www.theses.fr/1987PA077255.

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On etudie les odontocetes de la formation pisco, perou. Les formes pliocenes proviennent en majeure partie du gisement de sud sacaco alors que les formes miocenes proviennent d'aguada de lomas, d'el jahuay, de cerro la bruja et de santa rossa. L'etude de detail permet la reconnaissance de nouveaux genres et de nouvelles especes et de reviser la phylogenie et la taxinomie de tous les groupes d'odontocetes fossiles et actuels, et de preciser le polyphyletisme des dauphins de riviere (platanistoidea). Toutes les donnees utiles concernant le genre considere, son espece-type et le specimen-type sur lequel elle est fondee sont repertoriees dans un catalogue des odontocetes fossiles
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3

Bouetel, Virginie. "Les “Cetotheriidae” (Mammalia, Cetacea, Mysticeti) de la Formation Pisco (Miocène inférieur – Pliocène inférieur) de la côte péruvienne : Relations phylogénétiques et affinités des “Cetotheriidae”." Paris, Muséum national d'histoire naturelle, 2005. http://www.theses.fr/2005MNHN0017.

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Анотація:
Les mysticètes à fanons comprennent généralement quatre familles actuelles et une famille fossile: les Cetotheriidae s. L. Dépourvus des synapomorphies des mysticètes actuels, ces fossiles sont un groupe paraphylétique peu étudié. La description de trois nouveaux taxons fossiles (Piscobalaena nana et deux nouveaux genres) de la Formation Pisco (Néogène, Pérou) a mis en évidence de nouveaux caractères morphologiques. Les Balaenopteridae ont une stratégie de nutrition très particulière à laquelle sont associés des caractères morphologiques du crâne et du dentaire. Six taxons fossiles présentent certains de ces caractères. Ils pourraient donc être phylogénétiquement proches des ces derniers et avoir utilisé la même stratégie nutritionnelle. L'analyse cladistique de 54 caractères (crâne, région auditive et dentaire) de 25 taxons suggère que huit des 15 taxons fossiles étudiés forment un clade : les Cetotheriidae s. S. Son groupe-frère comprend les taxons actuels et cinq fossiles
Baleen mysticetes traditionally comprise four living families and a fifth exclusively fossil family: the Cetotheriidae s. L. . New material (Piscobalaena nana and two new genera) from the Neogene Pisco Formation of Peru, yield new morphological data. Balaenopteridae have a peculiar feeding behaviour associated with some morphological characters of the skull and dentary. Six fossil taxa present similar morphologies. Thus they could be phylogenetically close to Balaenopteridae and could have used the same feeding behaviour. The cladistic analysis of 54 characters (skull, auditory area, dentary) of 25 taxa suggests that eight of the 15 studied Cetotheriidae s. L. Constitute a clade: the Cetotheriidae s. S. Its sister-group includes the extant taxa and five fossil taxa
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Книги з теми "Cetacea, Fossil"

1

Mchedlidze, G. A. Fossil Cetacea of the Caucasus. Edited by Whitmore Frank C. Washington, D.C: Smithsonian Institution Libraries and National Science Foundation, 1988.

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2

Mchedlidze, G. A. Fossil Cetacea of the Caucasus. Edited by Whitmore Frank C. Rotterdam: A.A. Balkema, 1988.

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3

Lo, Che-hsi. Terrestrial mesonychia to aquatic cetacea: Transformation of the basicranium and evolution of hearing in whales. Ann Arbor, Mich: Museum of Paleontology, University of Michigan, 1999.

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4

Mchedlidze, G. A. General features of the paleobiological evolution of Cetacea. Rotterdam: A. A. Balkema, 1986.

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5

Pilleri, Georg. Contributions to the paleontology of some Tethyan Cetacea and Sirenia (Mammalia). [Berne], Switzerland: Brain Anatomy Institute, University of Berne, Ostermundigen, 1988.

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6

Pilleri, Georg. The Oligo-Miocene Cetacea of the Italian waters with a bibliography of the fossil Cetacea of Italy, 1670-1986. Ostermundigen, Switzerland: Brain Anatomy Institute, 1986.

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7

Pilleri, Georg. The Oligo-Miocene Cetacea of the Italian waters with a bibliography of the fossil Cetacea of Italy, 1670-1986. Ostermundigen, Switzerland: Brain Anatomy Institute, 1986.

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8

Pilleri, Georg. The Miocene Cetacea of the Belluno sandstones (Eastern Southern Alps). Padova: Società cooperativa tip., 1985.

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9

M, Schoch Robert, ed. Horns, tusks, and flippers: The evolution of hoofed mammals. Baltimore: Johns Hopkins University Press, 2002.

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10

Uhen, Mark D. Form, function, and anatomy of Dorudon atrox (Mammalia, Cetacea): An archaeocete from the middle to late Eocene of Egypt. Ann Arbor, Mich: University of Michigan, 2004.

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Частини книг з теми "Cetacea, Fossil"

1

Noelle Cooper, Lisa, Tobin L. Hieronymus, Christopher J. Vinyard, Sunil Bajpai, and J. G. M. Thewissen. "New Applications for Constrained Ordination: Reconstructing Feeding Behaviors in Fossil Remingtonocetinae (Cetacea: Mammalia)." In Topics in Geobiology, 89–107. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-8721-5_5.

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2

Bianucci, Giovanni, and Walter Landini. "Fossil History." In Reproductive Biology and Phylogeny of Cetacea, 35–93. Science Publishers, 2007. http://dx.doi.org/10.1201/b11001-3.

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3

"Cetacean Fossil Record." In Cetacean Paleobiology, 19–43. Chichester, UK: John Wiley & Sons, Ltd, 2016. http://dx.doi.org/10.1002/9781118561546.ch2.

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4

Fordyce, R. Ewan. "Cetacean Fossil Record." In Encyclopedia of Marine Mammals, 207–15. Elsevier, 2009. http://dx.doi.org/10.1016/b978-0-12-373553-9.00054-7.

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5

"Fossil Evidence of Cetacean Biology." In Cetacean Paleobiology, 198–238. Chichester, UK: John Wiley & Sons, Ltd, 2016. http://dx.doi.org/10.1002/9781118561546.ch6.

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6

Peri, Emanuele, Alberto Collareta, Gianni Insacco, and Giovanni Bianucci. "An Inticetus-like (Cetacea, Odontoceti) cheek tooth from the Pietra Leccese (Miocene, Southern Italy)." In Fossilia - Reports in Palaeontology, 33–35. Saverio Bartolini Lucenti, 2018. http://dx.doi.org/10.32774/fosreppal.20.1810.113335.

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Pesci, Fabio, Alberto Collareta, Chiara Tinelli, and Giovanni Bianucci. "First record of Monodontidae (Cetacea, Odontoceti) in the Mediterranean Basin from the Pliocene sands of Arcille (Grosseto, Tuscany, Italy)." In Fossilia - Reports in Palaeontology, 37–39. Saverio Bartolini Lucenti, 2018. http://dx.doi.org/10.32774/fosreppal.20.1810.123739.

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8

M., Feroskhan, and Saleel Ismail. "Simultaneous Reduction of NOx and Smoke Emissions in Dual Fuel and HCCI Engines Operated on Biogas." In Recent Technologies for Enhancing Performance and Reducing Emissions in Diesel Engines, 105–37. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-2539-5.ch006.

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Biogas has emerged as a promising alternative to fossil fuels in internal combustion engines in recent times. It could be used as the primary fuel in Compression Ignition (CI) engines in combination with a small quantity of a high cetane fuel in two modes – dual fuel or Homogeneous Charge Compression Ignition (HCCI). This chapter compares the performance, combustion, and emission parameters of a CI engine operated with biogas in dual fuel and HCCI modes vis-à-vis conventional diesel operation. The effects of biogas composition (quantified in terms of the methane content), location of secondary fuel injection and engine load are investigated. It is observed that the use of biogas has the potential to reduce both NOx and smoke emissions simultaneously, with HCCI mode offering ultra-low emissions. Operating the engine in dual fuel mode can provide high thermal efficiency and significant diesel substitution.
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Dominici, Stefano, Simone Cau, and Alessandro Freschi. "Stratigraphic paleobiology of an evolutionary radiation: taphonomy and facies distribution of cetaceans in the last 23 million years." In Fossilia - Reports in Palaeontology, 15–17. Saverio Bartolini Lucenti, 2018. http://dx.doi.org/10.32774/fosreppal.20.1810.051517.

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Тези доповідей конференцій з теми "Cetacea, Fossil"

1

Polokoff, Hannah, and Samuel J. Hampton. "WAIMA FORMATION FOSSIL: A POSSIBLE AQUATINIAN CETACEAN." In GSA 2020 Connects Online. Geological Society of America, 2020. http://dx.doi.org/10.1130/abs/2020am-359481.

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2

Kessler, Travis, Thomas Schwartz, Hsi-Wu Wong, and J. Hunter Mack. "Screening Compounds for Fast Pyrolysis and Catalytic Biofuel Upgrading Using Artificial Neural Networks." In ASME 2019 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/icef2019-7170.

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Abstract There is significant interest among researchers in finding economically sustainable alternatives to fossil-derived drop-in fuels and fuel additives. Fast pyrolysis, a method for converting biomass into liquid hydrocarbons with the potential for use as fuels or fuel additives, is a promising technology that can be two to three times less expensive at scale when compared to alternative approaches such as gasification and fermentation. However, many bio-oils directly derived from fast pyrolysis have a high oxygen content and high acidity, indicating poor performance in diesel engines when used as fuels or fuel additives. Thus, a combination of selective fast pyrolysis and chemical catalysis could produce tuned bioblendstocks that perform optimally in diesel engines. The variance in performance for derived compounds introduces a feedback loop in researching acceptable fuels and fuel additives, as various combustion properties for these compounds must be determined after pyrolysis and catalytic upgrading occurs. The present work aims to reduce this feedback loop by utilizing artificial neural networks trained with quantitative structure-property relationship values to preemptively screen pure component compounds that will be produced from fast pyrolysis and catalytic upgrading. The quantitative structure-property relationship values selected as inputs for models are discussed, the cetane number and sooting propensity of compounds derived from the catalytic upgrading of phenol are predicted, and the viability of these compounds as fuels and fuel additives is analyzed. The model constructed to predict cetane number has a test set prediction root-mean-squared error of 9.874 cetane units, and the model constructed to predict yield sooting index has a test set prediction root-mean-squared error of 13.478 yield sooting index units (on the unified scale).
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3

Shahsavan, Martia, Mohammadrasool Morovatiyan, Mammadbaghir Baghirzade, and J. Hunter Mack. "Implementing Natural Gas in a Compression Ignition Cycle Using Noble Gas Addition." In ASME 2019 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/icef2019-7159.

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Abstract Natural gas is known as a relatively clean fossil fuel due to its low carbon to hydrogen ratio compared to other transportation fuels, which yields a reduction of carbon monoxide, carbon dioxide, and unburned hydrocarbons emissions. However, it has a low cetane number, which makes it a difficult fuel for use in compression ignition engines. A potential solution for this issue can be adding small amounts of argon, as a noble gas with a low specific heat to modify the intake conditions. In this numerical study, a commercial compression ignition engine has been modeled to evaluate the auto-ignition of natural gas with the modified intake conditions. Different amounts of argon added to the intake air are examined in order to attain the optimal operating conditions. A detailed chemistry solver is implemented on a 53-species chemical kinetics mechanism to calculate the rate constants. The results show that compression ignition of natural gas can be achieved by adding small amounts of argon to the intake air. It drastically increases the in-cylinder temperature and pressure near TDC, which enables the auto-ignition of the injected natural gas. Moreover, it leads to the reduction in ignition delay and heat release rate, and expands the combustion duration. Emissions analysis indicates that NOx and CO2 can be significantly diminished by increasing the amount of argon in the intake composition. This study introduces an efficient and clean compression ignition engine fueled with natural gas running in optimal operating conditions using argon addition to the intake.
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4

Ramírez, Anita I., Sibendu Som, Lisa A. LaRocco, Timothy P. Rutter, and Douglas E. Longman. "Investigating the Use of Heavy Alcohols as a Fuel Blending Agent for Compression Ignition Engine Applications." In ASME 2012 Internal Combustion Engine Division Spring Technical Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ices2012-81169.

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There has been an extensive worldwide search for alternate fuels that fit with the existing infrastructure and would thus displace fossil-based resources. In metabolic engineering work at Argonne National Laboratory, strains of fuel have been designed that can be produced in large quantities by photosynthetic bacteria, eventually producing a heavy alcohol called phytol (C20H40O). Phytol’s physical and chemical properties (cetane number, heat of combustion, heat of vaporization, density, surface tension, vapor pressure, etc.) correspond in magnitude to those of diesel fuel, suggesting that phytol might be a good blending agent in compression ignition (CI) engine applications. The main reason for this study was to investigate the feasibility of using phytol as a blending agent with diesel; this was done by comparing the performance and emission characteristics of different blends of phytol (5%, 10%, 20% by volume) with diesel. The experimental research was performed on a single-cylinder engine under conventional operating conditions. Since phytol’s viscosity is much higher than that of diesel, higher-injection-pressure cases were investigated to ensure the delivery of fuel into the combustion chamber was sufficient. The influence of the fuel’s chemical composition on performance and emission characteristics was captured by doing an injection timing sweep. Combustion characteristics as shown in the cylinder pressure trace were comparable for the diesel and all the blends of phytol at each of the injection timings. The 5% and 10% blends show lower CO and similar NOx values. However, the 20% blend shows higher NOx and CO emissions, indicating that the chemical and physical properties have been altered substantially at this higher percentage. The combustion event was depicted by performing high-speed natural luminosity imaging using endoscopy. This revealed that the higher in-cylinder temperatures for the 20% blend are the cause for its higher NOx emissions. In addition, three-dimensional simulations of transient, turbulent nozzle flow were performed to compare the injection and cavitation characteristics of phytol and its blends. Specifically, area and discharge coefficients and mass flow rates of diesel and phytol blends were compared under corresponding engine operating conditions. The conclusion is that phytol may be a suitable blending agent with diesel fuel for CI applications.
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Srinivasan, K. K., P. J. Mago, G. J. Zdaniuk, L. M. Chamra, and K. C. Midkiff. "Improving the Efficiency of the Advanced Injection Low Pilot Ignited Natural Gas Engine Using Organic Rankine Cycles." In ASME 2007 Energy Sustainability Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/es2007-36151.

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Intense energy security debates amidst the ever increasing demand for energy in the country have provided sufficient impetus to investigate alternative and sustainable energy sources to the current fossil fuel driven economy. This paper presents the Advanced injection Low Pilot Ignition Natural Gas (ALPING) engine as a viable, efficient and low emissions alternative to conventional diesel engines, and discusses further efficiency improvements to the base ALPING engine using Organic Rankine Cycles (ORC) as bottoming cycles. The ALPING engine uses very small diesel pilots, injected early in the compression stroke to compression-ignite a premixed natural gas–air mixture. It is believed that the advanced injection of the higher cetane diesel fuel leads to longer incylinder residence times for the diesel droplets, thereby resulting in distributed ignition at multiple spatial locations, followed by lean combustion of the higher octane natural gas fuel via localized flame propagation. The multiple ignition centers result in faster combustion rates and higher fuel conversion efficiencies. The lean combustion of natural gas leads to reduction in local temperatures and oxides of nitrogen (NOx) emissions, since NOx emissions scale with local temperatures. In addition, the lean combustion of natural gas is expected to produce very little particulate matter (PM) emissions (not measured). Representative baseline ALPING (60° BTDC pilot injection timing) (without the ORC) half load (1700 rev/min, 21 kW) operation efficiencies reported in this study are about 35 percent while the corresponding NOx emissions is about 0.02 g/kWh, which is much lower than EPA 2007 tier 4 heavy duty diesel engine statutes of 0.2 g/kWh. Furthermore, the possibility of improving fuel conversion efficiency at half load operation with Organic Rankine Cycles using “dry fluids” are discussed. Dry organic fluids, due to their lower critical points, make excellent choices for bottoming Rankine cycles. Moreover, previous studies indicate that “dry fluids” are more preferable compared to wet fluids because the need to superheat the fluid to extract work from the turbine is eliminated. It is estimated that ORC–turbocompounding results in fuel conversion efficiency improvements of the order of 10 percent while maintaining the essential low NOx characteristics of ALPING combustion.
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