The Great American Biotic Interchange is considered to be a punctuated process, primarily occurring during four major pulses that began approximately 2.5 Ma. Central America and southeastern Mexico have a poor fossil record of this dynamic faunal history due to tropical climates. Exploration of submerged caves in the Yucatán, particularly the natural trap Hoyo Negro, is exposing a rich and remarkably well-preserved late Pleistocene fauna. Radiometric dates on megafauna range from approximately 38 400-12 850 cal BP, and extinct species include the ursid Arctotherium wingei and canid Protocyon troglodytes. Both genera were previously thought to be indigenous to and confined to South America and appear to represent an instance of large placental mammals, descended from North American progenitors, migrating back north across the Panama Isthmus. This discovery expands the distribution of these carnivorans greater than 2000 km outside South America. Their presence along with a diverse sloth assemblage suggests a more complex history of these organisms in Middle America. We suggest that landscape and ecological changes caused by latest Pleistocene glaciation supported an interchange pulse that included A. wingei, P. troglodytes and Homo sapiens.

Šiame magistriniame darbe nagrinėjama gyvavimo ciklo metodika, kuri pritaikoma KU statomo Mokslinių tyrimo laivo korpuso suvirinimo metu išsiskiriančių emisijų skaičiavimui GaBi 6 programinės įrangos pagalba. Nagrinėjami du suvirinimo būdai, kurie buvo naudojami statant KU Mokslinių tyrimo laivą, t. y. lankinis suvirinimas po fliusu (SAW) ir lankinis suvirinimas lydžiuoju elektrodu apsauginėse dujose (MIG, MAG). / This master thesis examines the life cycle methodology that adjusts constructed KU research vessel shell weld calculation of emissions released from 6 GaBi software. Analyzed two welding techniques that have been used in the construction of KU research vessel - submerged arc welding (SAW) and arc welding electrode deposits for gas shielded (MIG, MAG).

The beginnings of metallurgical activity have intrigued scholars for decades. In this dissertation, I explore early metallurgical activity on the Iranian Plateau represented by the evidence at Tal-i Iblis in southern Iran, and Seh Gabi and Godin Tepe in central northern Iran. Together, these sites offer a diachronic view of metal production on the Plateau as well as a view of metallurgical activities practiced at different scales of production. The metallurgical materials from Tal-i Iblis are firmly dated to the late 6th to early 5th millennia BCE, and this corpus includes hundreds of crucible fragments excavated from multiple trash dumps. Seh Gabi and Godin Tepe offer a smaller range of production materials from the 4th through 2nd millennia BCE, but they also include a large collection of finished metal objects. These later materials differ in style and process from the Iblis debris.Thorough examination of these artifacts, combined with comparison to a series of carefully controlled casting experiments, has returned numerous significant results. The metallurgy of the Iranian Plateau does not fit the standard model of early metallurgical development. The Iblis crucibles do not reflect an early "experimental" stage in copper production. Rather, these artifacts represent a carefully controlled, production process with a narrow range of variability in both temperature and reducing atmosphere. Further, there is clear evidence for the preference of arsenical-copper alloys at Tal-i Iblis. These ancient craftspeople sought high-quality ores from a source (the Talmessi copper deposit) over 500 km from their production facility.Metallurgical production on the Iranian Plateau is also characterized by the long-term use of crucibles as the primary reaction vessel well into the 2nd millennium BCE. There are some production centers on the Iranian Plateau that see the use of furnaces during the 3rd millennium, but crucible use persists at many sites. At Godin Tepe--a site with significant evidence for contact with the Mesopotamian lowlands--variability in crucible form increases in later periods to include an Egyptian-style crucible during the 2nd millennium BCE. The presence of this crucible suggests that there was contact with foreign metallurgical processes, but the preference for small, portable reaction vessels persisted.

Biocomposites have gained increasing attention in recent years. The environmental impacts of common plastics have led researchers and industrials to develop alternatives to fully petro-sourced materials (Beigbeder et al., 2019). This paper presents the results obtained from the life cycle assessments conducted for polystyrene (PS) and biocomposite DuraSense® Pure S40 Impact D (DS40). The aim is for DS40 to serve as a more environmentally friendly option to fossil-based plastic in the manufacturing and recycling of hangers. By replacing 40% of the fossil-based PS with wood fibers, DS40 gains an advantage with regard to its environmental impact. Exercising an LCA on a product offers the opportunity to analyze its environmental impacts and sustainability performance based on a cradle to grave perspective. Thus, to determine which factors that could create an adverse effect in the multiple lifecycles of hangers when recycled, four potential environmental factors were used for modelling several scenarios: loss in quality, end-of-life, travel distance, and packaging. The Global Warming Potential (GWP) - kg CO2 equivalent/functional unit was calculated using the GaBi Envision LCA software for each scenario, which subsequently were compared between PS and DS40. After the modelling of multiple scenarios, this study concludes that a hanger recycling system can be a viable activity due to the improved environmental sustainability. However, to remain as the alternative with the lowest GWP, it is necessary to keep what could be detrimental throughout the lives of the hangers made with DS40 to remain out of the loop. Preventing that the incorrect EoL is chosen, abstaining from the use of PE film as packaging, creating products with competent mechanical properties to have good longevity, and reducing the wasted material in each conversion step, make altogether the replacement of PS with DS40 in the production of hangers a less polluting alternative. The result showed that except for travel distance, all other factors considered have the potential to affect the GWP account, and with this, showing that there is more to consider than just the raw materials needed in the manufacturing of goods.

Made available in DSpace on 2015-02-24T19:48:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-06-10 / This dissertation the results of a research developed in the area of S?o Bento do Norte and Cai?ara do Norte, northern coast of the State of Rio Grande do Norte, during the period of June of 2000 to August of 2001, in the ambit of the projects MAMBMAR? (CNPq/CTPETRO) and PROBRAL (CAPES/DAAD). The objective principal of this research was the characterization of the sedimentary dynamics of this coast, with base in data of coastal process (winds, currents, waves and tides), with topographical risings (beach profiles and dunes), satellite images and sedimentary analyses. The more specific objectives were accomplished the coastal monitoring of this coast, to verify the maintenance of an erosive tendency or progradacional after the groynes construction for contention of the erosion in the beach of Cai?ara do Norte, as well as to verify the influence of the features of bottom of the platform interns adjacent on the pole petroliferous of Guamar?. The executed monitoramento allowed to identify that the movement of the sediments, along the year, in that area, is cyclical, reaching the largest oscillations during the months of winter (deposition) and they will summer (erosion). The sedimentologic studies indicated a general tendency for sands quartzosas, with gravel presence, moderately to good selected, with asymmetry predominantly negative. In agreement with the parameter of Dean (1957), used in the identification of the state morfodin?mico of the beaches, monitored beaches, are basically reflectivas with tendency to middlemen, what frames that space of the coast norte-riograndense, as a space strongly vulnerable to erosive processes. The studies developed in the platform, it interns of this area, allowed to visualize for the first time, in large scale, the distribution of the features of the submarine bottom to the batom?trico coat of 25 meters. Being pointed out the presence of a high one topographical submerged, with about 5 meters of height, 1 km of width and more than 24 meters of extension, located in the platform it interns in front of S?o Bento do Norte; coincident with the trend of the system of flaws of Carnaubais. This feature relay an important paper on the control of the sedimentary processes and oceanographic, as well as in the coastal evolution of this area of the RN state, and they affect the area of the pole petroliferous of Guamar? directly. These results contribute to a better knowledge of the processes in the area, and consequently as subsidies implantation of measures of coastal and environmental protection for the cities of S?o Bento do Norte and Cai?ara do Norte, as well as to understand how the geological-sedimentary processes and oceanographic, in this area, are influencing the characteristics geoambientais of the pole petroliferous of Guamar? / Esta disserta??o apresenta os resultados de uma pesquisa desenvolvida na regi?o de S?o Bento do Norte e Cai?ara do Norte, litoral setentrional do Estado do Rio Grande do Norte, durante o per?odo de Junho de 2000 a Agosto de 2001, no ?mbito dos projetos MAMBMAR? (CNPq/CTPETRO) e PROBRAL (CAPES/DAAD). O objetivo principal da pesquisa foi a caracteriza??o da din?mica sedimentar do litoral em quest?o, com base em dados relativos ? din?mica costeira (ventos, correntes, ondas e mar?s), levantamentos topogr?ficos (perfis de praia e dunas), imagens de sat?lite e an?lises sedimentol?gicas. Como objetivos espec?ficos foram realizados o monitoramento deste litoral, com o fim de verificar a manuten??o de uma tend?ncia erosiva ou progradacional ap?s a constru??o de gabi?es para conten??o da eros?o na praia de Cai?ara do Norte, bem como verificar a influ?ncia das fei??es de fundo da plataforma interna adjacente sobre o p?lo petrol?fero de Guamar?. O monitoramento executado permitiu identificar que a movimenta??o dos sedimentos, ao longo do ano, nessa regi?o, exibe um padr?o c?clico, atingindo as maiores oscila??es durante os meses de inverno (deposi??o) e ver?o (eros?o). Os estudos sedimentol?gicos indicaram uma tend?ncia geral para areias quartzosas, com presen?a de cascalho, moderadamente a bem selecionadas, com assimetria predominantemente negativa. De acordo com o par?metro de Dean (1957), as praias monitoradas s?o basicamente reflectivas com tend?ncia a intermedi?rias, o que enquadra esse trecho da costa norte-riograndense como fortemente vulner?vel a processos erosivos. Os estudos desenvolvidos na plataforma interna desta regi?o permitiram visualizar pela primeira vez, em macroescala, a distribui??o das fei??es do fundo submarino at? a is?bata de 25 metros. Ressaltando-se a presen?a de um alto topogr?fico submerso, com cerca de 5 metros de altura, 1 km de largura e mais de 24 metros de extens?o, localizado na plataforma interna em frente a cidade de S?o Bento do Norte, coincidente com o trend do Sistema de Falhas de Carnaubais. Esta fei??o exerce um papel importante no controle dos processos sedimentares e oceanogr?ficos, bem como na evolu??o costeira desta regi?o do Estado do RN, que afetam diretamente a regi?o do p?lo petrol?fero de Guamar?. Estes resultados contribuem para um melhor conhecimento dos processos atuantes na regi?o e, conseq?entemente, fornece subs?dios para a implementa??o de medidas de prote??o costeira e ambiental para as cidades de S?o Bento do Norte e Cai?ara do Norte, bem como para o melhor entendimento de modo como os processos geol?gicos e oceanogr?ficos atuantes nesta ?rea, v?m influenciando nas caracter?sticas geoambientais do p?lo petrol?fero de Guamar?