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Search Results: 1 - 10 of 144 matches for " tar "
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Chemical Analysis on Mongolia’s Natural Bitumen  [PDF]
Erdenetsogt Bat-Erdene, Batdelger Byambagar, Erdenee Enkhtsetseg, Budeebazar Avid
Advances in Chemical Engineering and Science (ACES) , 2014, DOI: 10.4236/aces.2014.42021
Abstract:

To extract pure bitumen, the bitumen from Bayan-Erkhet, Zuunbayan and Ukhaa was prepared into small particles of 0.2 - 0.5 cm and then it was infused with chloroform in the Soxhlet apparatus [1] [2]. The physical-mechanical properties were identified after the solvent was extracted from the chloroform infused bitumen through the vacuum evaporation method. The characteristics of the debris without bitumen or the remains after the infusion were examined in details. The hydrocarbon content of the bitumen was identified with the device: Agilent 7890-5975c Gas chromatography mass spectrometer.

Corrosion Study of AISI 304, AISI 321 and AISI 430 Stainless Steels in a Tar Sand Digester  [PDF]
L.E. Umoru, A.A. Afonja, B. Ademodi
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2008, DOI: 10.4236/jmmce.2008.74022
Abstract: This work has investigated the corrosion properties of three types of stainless steels in a tar sand digester environment with the aim of establishing their relative resistances in the environment. The corrosion experiments for the stainless steels were conducted by the non-electrochemical immersion technique with corrosion rates expressed in mils per year (mpy). The spectroscopy analysis of the Nigerian tar sand was done by the energy dispersive x-ray analysis. The surface study of the corroded stainless steels was accomplished via a scanning electron microscopy (SEM) to reveal the form of corrosion. The results of the corrosion experiments show that all the stainless steels have a relatively low corrosion rates (<5mpy). The SEM analyses of their corroded surfaces however revealed great tendency in them to exhibit crevice and pitting corrosions. On the basis of resistance to the two forms of corrosion the AISI 321 stainless steel exhibited the best resistance in the environment.
Use of olive oil for cleaning of hot tar burn
Murat ERSEL,Ersin AKSAY,Murat OZSARAC,Bulent YUKSEL
Turkish Journal of Emergency Medicine , 2009,
Abstract: Hot tar burns and removal of tar are unusual emergencies seen in the emergency departments. Because of the dense structure, cleaning difficulties and high temperature of the tar, tar burns requires a different management than the other burns. We present a 32 year old man who presents to our emergency department with hot tar burn.
Numerical Simulation of Partial Combustion for Biomass Tar Elimination in Two-Stage Gasifier  [PDF]
Shanhui Zhao, Yi Su, Wenguang Wu, Yunliang Zhang, Yun Wang, Yonghao Luo
Journal of Sustainable Bioenergy Systems (JSBS) , 2013, DOI: 10.4236/jsbs.2013.31012
Abstract:

Biomass tar is an obstacle in biomass gasification. Partial combustion is a potential method for tar elimination. To better study the tar conversion conditions and design reasonable partial combustion reactor, 2D/3D throat models are establish to calculate the tar reduction during partial combustion using numerical method. Different number of nozzles, injection directions and injection velocities were investigated. SIMPLE algorithm was used in this calculation. The results indicated that the best performance of partial combustion was obtained when ER (equivalent ratio) = 0.34. A performance of 3 nozzles, perpendicular injection and 20 m/s injection velocity could reach lowest tar content of 3.09 wt%.

Physicochemical Characterisation of Soils at the Gold Exploitation Sites of Bétaré-Oya District in Cameroon and Pollution Evaluation  [PDF]
Nchare Mominou, Yaya Al Issah, Bahodock Sarki, Elvis Kah
Open Journal of Inorganic Chemistry (OJIC) , 2018, DOI: 10.4236/ojic.2018.83007
Abstract: Physicochemical characterization and pollution evaluation were performed on six gold mining sites at the locality of Bétaré-Oya in Cameroon. Twelve samples of twenty two sampled show contamination with arsenic, nickel and lead. Granulometric analysis performed on all samples show a predominance of coarse particle (>250 μm) and PH varying from 5.4 to 7. The pollution index and pollution load index show that primary gold exploitation site of Mbal, Nakayo and Kpawara are contaminated. The highest pollution index is recorded on releases from the primary gold mining sites of Mbal, Kpawara and Nyondéré, which means that one must have a watchful eye to the discharges produced by primary gold mining. Sorting the samples in descending order of pollution index yields: Mb3 > Kp1 > Kp2 > Mb2 > Mb1 > Mb4 > Kp3 > Na5; meaning that special emphasis should be placed on the monitoring of wash sludge such as those from the Mbal site (Mb3), where pollution index is equal to 36.29, as well as washed and waste rock.
Contribución al reconocimiento taxonómico y distribución geográfica de las tarántulas de la familia Theraphosidae (Aranae: Mygalomorphae) en Colombia
Jiménez Juan Jacobo,Flórez Eduardo,Bertani Rogerio
Acta Biológica Colombiana , 2004,
Abstract: Las tarántulas son un grupo importante en los ecosistemas tropicales, entre otras, por ser reguladores de poblaciones de otros organismos. Su vistosidad ha generado en Colombia un gran comercio ilegal de especies debido a su gran demanda en el exterior. Debido a la extracción indiscriminada de ejemplares de su medio natural, es probable que algunas especies se encuentren en algún grado de amenaza. Para Colombia se han reportado en la literatura mundial, un total de 18 especies distribuidas en 13 géneros de tarántulas de la Familia Theraphosidae, aunque el conocimiento de su taxonomía y distribución geográfica en el país es aún incipiente. Estos listados de especies se basan en registros esporádicos de determinaciones efectuadas en los siglos XIX y XX, varios de ellos problemáticos por falta de claridad taxonómica. El objetivo de este trabajo fué la realización de un estudio taxonómico de las tarántulas de la Familia Theraphosidae de Colombia, que permita su identificación a nivel de género y especie incluyendo datos de su distribución geográfica. El estudio se efectuó con base en los ejemplares depositados en la Colección Aracnológica del Instituto de Ciencias Naturales de la Universidad Nacional de Colombia, por ser la muestra más representativa de terafósidos en el país. El trabajo taxonómico se realizó en el Instituto Butantan, Brasil, mediante la revisión de caracteres morfológicos y comparaciones con material depositado en la Colección de este Instituto. Los resultados consignados en este estudio arrojan un listado de 20 especies distribuidas en 12 géneros, incluyendo tres posibles especies nuevas para la ciencia al igual que dos especies registradas por primera vez para Colombia. De igual forma, se presentan mapas de distribución geográfica para las especies determinadas y una clave taxonómica interactiva en formato CD-ROM, para la determinación de las especies consignadas. Esta información se constituye como herramienta básica para facilitar el desarrollo de estudios futuros de sus poblaciones y la delineación de medidas para su conservación, que eventualmente conduzcan al uso racional del recurso.
Eski Mezopotamya nan Sisteminin Yunanl lara Etkisi ( star- Aphrodite rne i)/// Impact of the Ancient Mesopotamian Belief System on Greeks ( star- Aphrodite Cases)
Yusuf KILI?,Ebru UNCU
History Studies : International Journal of History , 2011,
Abstract: Important interactions in the area of culture and religion among ancient societies are known to have existed with the increase of transportation and communication. Such interactions sometimes took place directly and sometimes by means of neighbor communities. In fact, every kind of interaction that took place among the societies of Ancient East and Ancient West had followed the same path. The similarity between goddesses tar-Aphrodite as the subject of our study reveals itself as an example to this issue and it also supports the view how much the Ancient Mesopotamian religious system had affected the Greek system. The main point here, within the current conditions of the age, is to reveal the cultural interaction network clearly between these quiet distant societies. At that point, the Hurrians and Phoenicians come to scene.
Topical coal tar alone and in combination with oral methotrexate in management of psoriasis : a retrospective analysis
Prasad PVS,John Felix
Indian Journal of Dermatology, Venereology and Leprology , 1997,
Abstract: Thirty five patients admitted with psoriasis were analysed. 16 patients received 20% crude coal tar and 19 patients received 20% crude coal tar along with methotrexate in a weekly oral schedule (15mg/wk). After 4 weeks of therapy there was total clearence in 52.6% of the patients with combination therapy, whereas only 12.5% of the patients with conventional therapy achieved this.
Genotoxicity Assessment of Birch-Bark Tar—A Most Versatile Prehistoric Adhesive  [PDF]
A. Baumgartner, M. Sampol-Lopez, E. Cemeli, T. E. Schmid, A. A. Evans, R. E. Donahue, D. Anderson
Advances in Anthropology (AA) , 2012, DOI: 10.4236/aa.2012.22006
Abstract: In the Mesolithic, birch-bark tar was commonly utilized across Europe and much of Asia as an adhesive to bind, seal and coat surfaces, but also quite frequently it was found to be chewed. The tar is known to contain biomarker triterpenoid compounds like betulin, crucial in preserving food and for medical applications. Aqueous, ethanolic and DMSO extracts were prepared from solid birch-bark tar and evaluated in vitro for the induction of DNA damage using Comet, micronucleus and sister-chromatid-exchange assays. Additionally, apoptosis induction was assessed. For the ethanolic extract, only the Comet assay showed a significant increase of DNA damage. All three extracts were able to significantly induce apoptosis. Thus, birch-bark tar seems capable of inducing genotoxic damage as well as apoptotic effects possibly originating from the triterpenoids’ antimicrobial properties. We examine why prehistoric tar is found with tooth marks, the beneficial effects of birch-bark tar, and evidence for increased genotoxic risk upon exposure.
Development of a Raoult’s Law-Based Screening-Level Risk Assessment Methodology for Coal Tar and Its Application to Ten Tars Obtained from Former Manufactured Gas Plants in the Eastern United States  [PDF]
Derick G. Brown
Journal of Environmental Protection (JEP) , 2013, DOI: 10.4236/jep.2013.46A001
Abstract:

A Raoult’s law-based screening-level assessment methodology was developed to calculate the carcinogenic and non-carcinogenic risks from ingestion of coal tar-contaminated water and it was applied to ten coal tars obtained from sites in the eastern United States. This approach provides a simple risk screening based on the conservative assumptions of Tier 1 in both the ASTM RBCA methodology and the USEPA Soil Screening Guidance. Results across the ten tars exhibited similar patterns, even though the coal tars had significantly different chemical compositions, and in all cases the screening-level risks were above the USEPA thresholds. There was no appreciable difference in the total risks when using either the current USEPA 1993 PAH risk assessment guidance or the proposed 2010 guidance. Benzene, while present at low concentrations within the coal tars, posed the dominant risk and strong correlations were observed with the benzene mole fraction.

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