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Relevant bibliographies by topics / Invisible gold

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Academic literature on the topic 'Invisible gold'

Author: Grafiati

Published: 10 December 2022

Last updated: 28 January 2023

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Journal articles on the topic "Invisible gold"

1

Volkov, A. V., and A. A. Sidorov. "Invisible gold." Herald of the Russian Academy of Sciences 87, no. 1 (January 2017): 40–48. http://dx.doi.org/10.1134/s1019331617010051.

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Asadi, H. H., J. H. L. Voncken, and M. Hale. "Invisible gold at Zarshuran, Iran." Economic Geology 94, no. 8 (December 1, 1999): 1367–74. http://dx.doi.org/10.2113/gsecongeo.94.8.1367.

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Ciobanu, Cristiana L., Nigel J. Cook, Allan Pring, Joël Brugger, Leonid V. Danyushevsky, and Masaaki Shimizu. "‘Invisible gold’ in bismuth chalcogenides." Geochimica et Cosmochimica Acta 73, no. 7 (April 2009): 1970–99. http://dx.doi.org/10.1016/j.gca.2009.01.006.

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Large, Ross R., and Valeriy V. Maslennikov. "Invisible Gold Paragenesis and Geochemistry in Pyrite from Orogenic and Sediment-Hosted Gold Deposits." Minerals 10, no. 4 (April 9, 2020): 339. http://dx.doi.org/10.3390/min10040339.

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LA-ICPMS analysis of pyrite in ten gold deposits is used to determine the precise siting of invisible gold within pyrite, and thus the timing of gold introduction relative to the growth of pyrite and related orogenic events. A spectrum of invisible gold relationships in pyrite has been observed which suggests that, relative to orogenic pyrite growth, gold introduction in some deposits is early at the start of pyrite growth; in other deposits, it is late toward the end of pyrite growth and in a third case, it may be introduced at the intermediate stage of orogenic pyrite growth. In addition, we report a distinct chemical association of invisible gold in pyrite in the deposits studied. For example, in the Gold Quarry (Carlin type), Mt Olympus, Macraes and Konkera, the invisible gold is principally related to the arsenic content of pyrite. In contrast, in Kumtor and Geita Hill, the invisible gold is principally related to the tellurium content of pyrite. Other deposits (Golden Mile, Bendigo, Spanish Mountain, Witwatersrand Carbon Leader Reef (CLR)) exhibit both the Au-As and Au-Te association in pyrite. Some deposits of the Au-As association have late orogenic Au-As-rich rims on pyrite, which substantially increase the value of the ore. In contrast, deposits of the Au-Te association are not known to have Au-rich rims on pyrite but contain nano- to micro-inclusions of Au-Ag-(Pb-Bi) tellurides.

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MacKenzie, Doug, Dave Craw, and Craig Finnigan. "Lithologically controlled invisible gold, Yukon, Canada." Mineralium Deposita 50, no. 2 (June 12, 2014): 141–57. http://dx.doi.org/10.1007/s00126-014-0532-5.

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Bustos Rodriguez, H., D. Oyola Lozano, Y. A. Rojas Martínez, G. A. Pérez Alcázar, and A. G. Balogh. "Invisible gold in Colombian auriferous soils." Hyperfine Interactions 166, no. 1-4 (November 3, 2006): 605–11. http://dx.doi.org/10.1007/s10751-006-9327-0.

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Vikentyev, Ilya, Olga Vikent’eva, Eugenia Tyukova, Maximilian Nikolsky, Julia Ivanova, Nina Sidorova, Dmitry Tonkacheev, et al. "Noble Metal Speciations in Hydrothermal Sulphides." Minerals 11, no. 5 (May 3, 2021): 488. http://dx.doi.org/10.3390/min11050488.

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A significant part of the primary gold reserves in the world is contained in sulphide ores, many types of which are refractory in gold processing. The deposits of refractory sulphide ores will be the main potential source of gold production in the future. The refractory gold and silver in sulphide ores can be associated with micro- and nano-sized inclusions of Au and Ag minerals as well as isomorphous, adsorbed and other species of noble metals (NM) not thoroughly investigated. For gold and gold-bearing deposits of the Urals, distribution and forms of NM were studied in base metal sulphides by laser ablation-inductively coupled plasma mass spectrometry and by neutron activation analysis. Composition of arsenopyrite and As-pyrite, proper Au and Ag minerals were identified using electron probe microanalysis. The ratio of various forms of invisible gold—which includes nanoparticles and chemically bound gold—in sulphides is discussed. Observations were also performed on about 120 synthetic crystals of NM-doped sphalerite and greenockite. In VMS ores with increasing metamorphism, CAu and CAg in the major sulphides (sphalerite, chalcopyrite, pyrite) generally decrease. A portion of invisible gold also decreases —from ~65–85% to ~35–60% of the total Au. As a result of recrystallisation of ores, the invisible gold is enlarged and passes into the visible state as native gold, Au-Ag tellurides and sulphides. In the gold deposits of the Urals, the portion of invisible gold is usually <30% of the bulk Au.

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Spry, P. G., and S. E. Thieben. "The distribution and recovery of gold in the Golden Sunlight gold-silver telluride deposit, Montana, U.S.A." Mineralogical Magazine 64, no. 1 (February 2000): 31–42. http://dx.doi.org/10.1180/002646100549111.

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AbstractThe gold balance in an ore deposit where the ore is treated by cyanide is the sum of the ‘visible gold’ that is amenable to cyanidation and ‘visible gold’ and the ‘invisible gold’, which are not amenable to cyanidation. Petrographic analyses, electron and ion microprobe as well as scanning electron microscope studies of ore from the Golden Sunlight deposit, Montana, suggest that periods of relatively poor gold recoveries are primarily due to the presence of inclusions, <25 µm in size, of native gold, petzite, calaverite, buckhornite and krennerite. These are encapsulated in cyanide insoluble grains of pyrite, chalcopyrite and tennantite and are present in the tailings. This contribution probably accounts for 3–25% of the unrecoverable gold processed during the life of the mine. Minor amounts (6–7%) of ‘invisible gold’, as indicated by ion microprobe studies and the presence of up to 5% ‘visible gold’ in buckhornite, which is rare in nature, appears to account for the remainder of the gold budget.

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Li, Chang-Ping, Jun-Feng Shen, Sheng-Rong Li, Yuan Liu, and Fu-Xing Liu. "In–Situ LA-ICP-MS Trace Elements Analysis of Pyrite and the Physicochemical Conditions of Telluride Formation at the Baiyun Gold Deposit, North East China: Implications for Gold Distribution and Deposition." Minerals 9, no. 2 (February 22, 2019): 129. http://dx.doi.org/10.3390/min9020129.

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The Baiyun gold deposit is located in the northeastern North China Craton (NCC) where major ore types include Si-K altered rock and auriferous quartz veins. Sulfide minerals are dominated by pyrite, with minor amounts of chalcopyrite, sphalerite and galena. Combined petrological observations, backscattered electron image (BSE) and laser ablation analysis (LA-ICP-MS) have been conducted on pyrite to reveal its textural and compositional evolution. Three generations of pyrite can be identified—Py1, Py2 and Py3 from early to late. The coarse-grained, porous and euhedral to subhedral Py1 (mostly 200–500 μm) from the K-feldspar altered zone is the earliest. Compositionally, they are enriched in As (up to 11541 ppm) but depleted in Au (generally less than 10 ppm). The signal intensity of Au is higher than background values by two orders of magnitude and shows smooth spectra, indicating that invisible gold exists as homogeneously or nanoscale-inclusions in Py1. Anhedral to subhedral Py2 grains (generally ranging 500–1500 μm) coexist with other sulfides such as chalcopyrite, sphalerite and galena in the early silicification stage (gray quartz). They have many visible gold grains and contain little amounts of invisible Au. Notably, visible gold has an affinity with micro-fractures formed due to late deformation, implying that native gold may have resulted from mobilization of preexisting invisible gold in the structure of Py2 grains. Subsequently Py3 occurs as very fine-grained disseminations of euhedral crystals (0.05–1 mm) in late silicification stage (milky quartz) and coexists with tellurides (e.g. petzite, calaverite and hessite). They contain the highest level of invisible gold with positive correlations between Au-Ag-Te. In the depth profiles of Py3, the smooth Au spectra mirror those of Te with high intensities, revealing that gold occurred as homogeneously/nanoscale-inclusions and submicroscopic Au-bearing telluride inclusions in pyrite grains. The high Te and low As in Py3, combined with high Au content, imply that invisible gold can be efficiently scavenged by Te. Abundant tellurides (petzite, calaverite and hessite) have been recognized in auriferous quartz veins. Lack of symbiosis sulfides with the tellurium assemblages indicates crystallization under low fS2 and/or high fTe2 conditions and coincides with the result of thermodynamic calculations. High and markedly variable Co (from 0.24 to 2763 ppm, average 151.9 ppm) and Ni (from 1.16 to 4102 ppm, average 333.1 ppm) values suggest that ore-forming fluid may originate from a magmatically-derived hydrothermal system. Combined with previous geochronological data, the textural and compositional evolution of pyrite indicates that the Baiyun gold deposit has experienced a prolonged history of mineralization. In the late Triassic (220,230 Ma), the magmatic hydrothermal fluids, which had affinity with the post-collisional extensional tectonics on the NCC northern margin, caused initial gold enrichment. Then, as a result of deformation or the addition of new hydrothermal fluids, visible gold-rich Py2 was formed. The upwelling of mantle–derived magma brought in a lot of Te-rich ore-forming hydrothermal fluids during the peak of the destruction of the NCC (~120 Ma). Amount of visible/invisible gold and Au-Ag-Te mineral assemblages precipitated from these mineralized fluids when the physical and chemical conditions changed.

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Yang, Meizhi, Quan Wan, Xin Nie, Suxing Luo, Yuhong Fu, Ping Zeng, and Wenqi Luo. "Quantitative XPS characterization of “invisible gold” in Carlin-type gold ores through controlled acid erosion." Journal of Analytical Atomic Spectrometry 36, no. 9 (2021): 1900–1911. http://dx.doi.org/10.1039/d1ja00102g.

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Quantitative XPS analysis of “invisible gold” in Carlin-type gold ores was accomplished, which revealed Au concentration, percentages of Au+ and Au0, and Au NP size. An acid etching step was demonstrated to be the key to enhancing Au signal in XPS.

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Dissertations / Theses on the topic "Invisible gold"

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Armstrong, John P. "Variations in silicate and sulphide mineral chemistry between free-milling metallic and refractory invisible gold ores, Con Mine, Yellowknife, Northwest Territories." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ28472.pdf.

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Rosén, Josefine. "Invisible Weapons : Hegemony and Binary Relationships in Chinua Achebe’s Arrow of God." Thesis, Mittuniversitetet, Institutionen för humaniora, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-11215.

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Law, Wun-Sheng. "Institutional altruism, invisible hands, and Good Samaritans : an anthropological examination of Hong Kong's Community Chest charity organization." Thesis, SOAS, University of London, 1997. http://eprints.soas.ac.uk/28504/.

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The discipline of social anthropology has been remarkably inattentive to the phenomenon and organizational practices of 'charity', and, associatedly, has been non-discursive in its treatment of social welfare. In this thesis, I endeavour to indicate that this disciplinary ignorance of charity and social welfare is to be regretted. Through my case-study analysis of the role of a key charitable organization in Hong Kong I hope to convince my readers of the relatively untapped potential of 'an anthropology of charity'. Cultural practices of charity and social welfare are sociologically significant and interesting in their own right, but can also illuminate wider social and political processes and structures from an unusual perspective. Attention to 'charity' has much to offer anthropology, but the obverse also holds, understandably, not been properly mindful of anthropological - particularly ethnographic - approaches. The nucleus of my research is the Community Chest, the most influential nongovernmental charitable organization in the colony (soon to be post-colony) of Hong Kong. In my thesis I examine inter cilia: the setting in which the Community Chest operates; its organizational structures and procedures; the cultural logic of donation; issues of entitlement; and the relationship between donors and recipients of charity. Throughout I am attentive to the linkages between charity provided by fiat is often called 'the voluntary sector', and social welfare as dispensed by the Hong Kong state. A key theme is the extent to which the Community Chest, despite its epithet as a nongovernmental organization, should be viewed as having a definite brokerage role between the state and Hong Kong's people. The institutionalization of altruism, which the Community Chest represents, does not escape the reach of the Hong Kong state. In a deliberate manner I utilize the Community Chest as a prism by which to scrutinize the 'borrowed time and borrowed place' that is contemporary Hong Kong. Not only is Hong Kong a global (and arguably postmodern) city, which has changed dynamically in recent decades, but existentially and psychologically its population is affected by the ever lurking shadow of the PRC regime to which Hong Kong will be handed over in July 1997. The Community Chest was established in 1968 at a time written both the Hong Kong state and society were undergoing radical changes. From the vantage point of the Community Chest I have been able to calibrate the transformations and continuities of the last three decades, and the not insignificant role played by charity and social welfare over that period. In addition to illuminating Hong Kong' s extraordinary contemporary situation, I hope also to have contributed to on-going theoretical debates in anthropology, sinology, and the social sciences generally. There is a burgeoning literature on gift exchange, entitlement, altruism, concepts of need and poverty, the role of NGOs in alleviating hardship, clientelism, and the role of mass media representations. I feel that my fieldwork research makes a contribution to discussion of each of these issues. My work contributes a further perspective from which to understand guanxi (personal networks) and renging (moral norms and human feelings) as axiomatic Chinese cultural constructions. I am also concerned with questions of citizenship, of community, of hybridity, of identity, of belonging, and of nationalism, all of which are especially fraught issues for people in contemporary Hong Kong. Finally, but deserving special mention - one of my chief ambitions has been to appraise the claims that the New Right makes for Hong Kong as the epitome of a ' leissez-faire' policy in which the state's interventions in terms of welfare provision are based on residualist principles. The New Right profess that Hong Kong is the free market economy, and that the voluntary sector and the market provide welfare effectively in the absence of state intervention. My research indicates that the Hong Kong state, despite its laissez-faire rhetoric, has been decisively interventionist. The Community Chest, set up ostensibly to generate and dispense charity from the voluntary sector, is ambivalently entangled with the hidden hands of both big business and the state.

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Booth, M. "Distribution and mineralogical association of Au at the Kanmantoo Cu-Au deposit." Thesis, 2018. http://hdl.handle.net/2440/130472.

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This item is only available electronically.
South Australia’s Kanmantoo Cu-Au deposit is currently operated by Hillgrove Resources and has an extended history of exploration and production dating back to 1846. However, there is little consensus on the paragenesis and structural controls of the deposit. Empirical work specifically on Au mineralogy and paragenesis has been completed. To investigate the mineralogical and geochemical associations between Au and host mineralogy, drill core samples, grab samples and ore concentrates and tailings have been collected from the East Kavanagh, Central Kavanagh, West Kavanagh, Spitfire and Nugent ore lodes. Petrographic analysis, Mineral Insights Goldsniffer analysis, secondary electron microscopy, mineral liberation analysis (SEM-MLA) and Laser Ablation (LA-ICP-MS) analysis observed and recorded evidence for four textural settings of Au. Two stages of Au development are proposed: early Au (associated with the main economic Cu-bearing hydrothermal fluids) and late Au (associated with retrograde Bi-rich hydrothermal fluids). Variations observed in major and trace element composition reflect changing input from a thermally-anomalous hydrothermal fluid source. The stability field for Au nanoparticles and the rarity of precipitated visible Au supports a late-peak to post-peak metamorphic origin. This study has implications about how Au can be recovered within the Kanmantoo Cu-Au deposit. The mineralogy and geochemical characteristics of Au at the Kanmantoo Cu-Au deposit can also be utilised as an exploration pathfinder within the greater Adelaide fold belt and the Delamarian-affected terrains at other exploration provinces within the Adelaide fold belt.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2018

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Wang, Chun-Wei, and 王駿偉. "Probing the Invisible Barrier of Cysteine Interfering the Stability of Pegylated Gold Nanoparticles in the Culture Medium." Thesis, 2017. http://ndltd.ncl.edu.tw/cgi-bin/gs32/gsweb.cgi/login?o=dnclcdr&s=id=%22105CYCU5795010%22.&searchmode=basic.

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碩士
中原大學
奈米科技碩士學位學程
105
Gold nanoparticles are a material of diagnosis and therapy in cancer medicine in recent years. Because of its high biocompatibility, excellent optical properties and extension, gold nanoparticles are usually utilized to biomedicine. Mononuclear phagocyte system (MPS) clears protein corona which is formed by attaching protein in blood to the nanomaterial and further becomes a biological barrier before the nanomaterial reaches the target. In this study, cysteine of small molecule in blood is a key to influence stability of gold nanoparticles. Macrophage plays an important role in constant cysteine and further becomes an important and invisible biological barrier of gold nanoparticles applications in vivo. First of all, RAW264.7 macrophage is utilized to co-culture with gold nanoparticles, serum protein, macrophage identification and nanomaterial clearance are observed by the dark-field microscope and further verify that PEGylated gold nanoparticles are able to escape from biological identification. Because polyethylene glycol has only 24hrs stability, DTNB(Ellman’s reagent) and fluorescent gold nanocluster are utilized to inspect amount of cysteine generated in macrophage medium through addition of cystine in medium or not. Therefore, long-term stability of PEGylated gold nanoparticles is explored by cystine. This study found that macrophage metabolizes additional cystine into cysteine in culture medium but could not be elevated without cystine addition. Constant cysteine in blood plays an important role to interfere the stability of gold nanoparticles. Proper nanoprobes design can enhance efficiency of nanomaterial applied for precision therapy when avoiding attacks of small molecule cysteine.

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Books on the topic "Invisible gold"

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Invisible gold in Asia: Creating wealth through intellectual property. Singapore: Marshall Cavendish Business, 2010.

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The invisible Harry Gold: The man who gave the Soviets the atom bomb. New Haven: Yale University Press, 2010.

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Invisible. Eugene Oregon: Harvest House Publishers, 2015.

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The invisible struggle. [Place of publication not identified]: [Xlibris Corp.], 2010.

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Arenas, Jimena Lobo Guerrero. Del texto contexto, y lugar del oro en la Crónica del Perú de Pedro Cieza de León: Que trata del autor, su vida y obra, la escritura de la historia y el lugar del oro, sea este moral, natural o invisible. Bogotá, D.C., Colombia: Universidad de los Andes, Facultad de Ciencias Sociales-Ceso, Departamento de Historia, 2008.

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Del texto contexto, y lugar del oro en la Crónica del Perú de Pedro Cieza de León: Que trata del autor, su vida y obra, la escritura de la historia y el lugar del oro, sea este moral, natural o invisible. Bogotá, D.C., Colombia: Universidad de los Andes, Facultad de Ciencias Sociales-Ceso, Departamento de Historia, 2008.

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The invisible hand: Do all things really work for good? Dallas: Word Pub., 1996.

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C, Sproul R. The invisible hand: Do all things really work for good? Phillipsburgs, N.J: P&R Pub., 2003.

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Bergeron, Lucie. La pierre invisible. Montréal: Québec Amérique jeunesse, 2009.

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Yancey, Philip. Reaching for the Invisible God. Grand Rapids: Zondervan, 2009.

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Book chapters on the topic "Invisible gold"

1

Andráš, Peter, and Martin Chovan. "Invisible gold in sulphides (Western Carpathians, Slovakia)." In Mineral Deposits at the Beginning of the 21st Century, 511–14. London: CRC Press, 2022. http://dx.doi.org/10.1201/9781003077503-130.

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Ajmera, Maya, and Gregory A. Fields. "Boxed in by Good Intentions—Working in Silos." In Invisible Children, 103–22. London: Palgrave Macmillan UK, 2016. http://dx.doi.org/10.1057/978-1-137-57838-9_5.

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Long, Brendan. "The invisible hand." In Adam Smith and the Invisible Hand of God, 133–71. London: Routledge, 2022. http://dx.doi.org/10.4324/9781003241379-6.

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McCloskey, Deirdre Nansen. "Life in the Market Is Good for You." In Accepting the Invisible Hand, 139–68. New York: Palgrave Macmillan US, 2010. http://dx.doi.org/10.1057/9780230114319_7.

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Long, Brendan. "Smith's Christian God." In Adam Smith and the Invisible Hand of God, 172–84. London: Routledge, 2022. http://dx.doi.org/10.4324/9781003241379-7.

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Baker, Jennifer A. "Don’t Let the Best Be the Enemy of the Good: A Stoic Defense of the Market." In Accepting the Invisible Hand, 69–86. New York: Palgrave Macmillan US, 2010. http://dx.doi.org/10.1057/9780230114319_4.

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George, Richard. "The Invisible Hand and Thinness of the Common Good." In Studies in Economic Ethics and Philosophy, 38–47. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-662-10347-0_3.

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Dutton, Paul Edward. "Carolingian Invisibles and Eriugena’s Lost Vision of God." In Seeing the Invisible in Late Antiquity and the Early Middle Ages, 463–78. Turnhout: Brepols Publishers, 2005. http://dx.doi.org/10.1484/m.usml-eb.3.2357.

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Long, Brendan. "Smith's Christian faith?" In Adam Smith and the Invisible Hand of God, 46–99. London: Routledge, 2022. http://dx.doi.org/10.4324/9781003241379-4.

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Long, Brendan. "Situating Smith." In Adam Smith and the Invisible Hand of God, 17–45. London: Routledge, 2022. http://dx.doi.org/10.4324/9781003241379-3.

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Conference papers on the topic "Invisible gold"

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Junussov, Medet. "“Looking for “invisible gold” and its concentrations in Arsenic-containing sulfide minerals of Bakyrchik gold deposits”." In MultiScience - XXXII. microCAD International Multidisciplinary Scientific Conference. University of Miskolc, 2018. http://dx.doi.org/10.26649/musci.2018.010.

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Bordini, Rogério Augusto, and Oliver Korn. "Strengthening Invisible Ties." In GoodIT 2022: ACM International Conference on Information Technology for Social Good. New York, NY, USA: ACM, 2022. http://dx.doi.org/10.1145/3524458.3548489.

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Lavalle, Julien, Jean-Michel Alimi, and André Fuözfa. "Cosmic ray positron excess: is the dark matter solution a good bet?" In INVISIBLE UNIVERSE: Proceedings of the Conference. AIP, 2010. http://dx.doi.org/10.1063/1.3462661.

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Burns, Alyxander, Thai On, Christiana Lee, Rachel Shapiro, Cindy Xiong, and Narges Mahyar. "Making the Invisible Visible: Risks and Benefits of Disclosing Metadata in Visualization." In 2021 IEEE Workshop on Visualization for Social Good (VIS4Good). IEEE, 2021. http://dx.doi.org/10.1109/vis4good54225.2021.00008.

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Landaeta Rivas, Fernando, Michael Cotten, Paulinus Bimastianto, Shreepad Khambete, Ara Krikor, Suhail Al Ameri, Erwan Couzigou, et al. "Real Time Data Analysis Unveils Potential Savings in Drilling Operations Through Invisible Lost Time Automated Tool." In ADIPEC. SPE, 2022. http://dx.doi.org/10.2118/211751-ms.

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Abstract Objectives/Scope: Traditionally Daily Drilling Reports were used as the main source of the data input for Invisible Lost Time calculations with great success. One observed drawback was that the hidden causes that lead to invisible lost time were not identified. This paper outlines the framework to incorporate Real-Time high frequency rig-floor sensor data in the invisible lost time calculation, identification, and reduction exercises. This approach breaks down, downhole activities into smaller, measurable, discrete sub-activities that are measured, benchmarked, and targeted for improvement. Methods, Procedures, Process: This paper covers three major downhole activities: Drilling, Tripping, and Running Casing, breaking them down into thirty-three sub-activities. A three-year drilling activities dataset is categorized into comparable groups based on drilling rig capabilities and formation characteristics. The sub-activities are then presented on a histogram with the average, P10, P50, and P95 values of each sub-activity determined based on a pre-accepted category. This benchmarking process enabled the generation of the targets that are currently being used for calculating and understanding the invisible lost time causes in the operation. Results, Observations, Conclusions: revious reporting would simply identify the phase of operation that is creating the invisible lost time. Complementing the existing Invisible Lost Time calculation model with Real-Time data has enabled the understanding of the operational steps that lead to sub-optimal performance. A good example of this would be the drilling phase. The new approach is able to pinpoint the steps in the drilling phase that generates the invisible lost time, for example when post-connection times are excessively exceeding historical norms. Another advantage is the ability to run the report in the middle of the activity and highlight that the current rate of execution is not optimal. This enables the supervisor to investigate the situation and propose solutions to improve performance on the ongoing activity. In addition, this approach has been used successfully for ranking the performance of casing running service companies and helping in the decision-making process for awarding new contracts.

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Chen, C. Q., P. T. Ng, G. B. Ang, Francis Rivai, A. C. T. Quah, H. P. Ng, P. C. Ang, J. Lam, and Z. H. Mai. "Electrical and Nanoprobing Analysis on the Implantation-Related Invisible Defect." In ISTFA 2016. ASM International, 2016. http://dx.doi.org/10.31399/asm.cp.istfa2016p0132.

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Abstract As semiconductor technology keeps scaling down, failure analysis and device characterizations become more and more challenging. Global fault isolation without detailed circuit information comprises the majority of foundry EFA cases. Certain suspected areas can be isolated, but further narrow-down of transistor and device performance is very important with regards to process monitoring and failure analysis. A nanoprobing methodology is widely applied in advanced failure analysis, especially during device level electrical characterization. It is useful to verify device performance and to prove the problematic structure electrically, especially for implantation related problems [1] [2]. Implantation related defects, or invisible defects, are the most challenging defect types for the application of fault isolation in all of the failure analysis jobs. The key challenge for these kinds of analyses is to make the defect visible. Sometimes, it is difficult or even impossible to visualize the defective point. Then, sufficient electrical evidence and theory analysis are important to bring the issue to resolution. For these kinds of analyses, a nanoprobing system is a necessary tool to conduct the detailed analysis. Combined with the device physics and electrical theory analysis, nanoprobing can bring out the perfect failure mechanism and problematic process step. There are two popular nanoprobing systems in our lab, one is SEM based and the other is AFM based. Both systems have their advantages and disadvantages in the electrical characterization and fault isolation field. In this paper, an implantation related issue was analyzed. Gross leakage was observed on the failed units as compared with good units. Global fault isolation, TIVA and EMMI failed to find the exclusive hotspot. With the GDS and process analysis, the nanoprobing was employed to the performance check on some of the suspected structures. Finally, the defective location was successfully isolated by nanoprobing. Combined with device physics and electrical analysis, the problematic process was successfully isolated.

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Zhu, David, Soh Ping Neo, Alfred Quah, Ghim Boon Ang, Lei Zhu, Yanhua Huang, Hong Tak Koo, Moi Kian Yau, Ma Hninhnin, and Nagalingam Dayanand. "A Systematic Failure Analysis to Reveal the Mystery of Lower N-Well Resistance." In ISTFA 2011. ASM International, 2011. http://dx.doi.org/10.31399/asm.cp.istfa2011p0185.

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Abstract In this paper, we will describe a low yield case which revealed itself as leakage failures near the wafer edge. A systematic problem solving approach was used based on the application of a variety of FA techniques such as electrical curve tracing, Spreading Resistance Probing (SRP), Secondary Ion Mass Spectrometry (SIMS), and Chemical Analysis coupled with extensive Fab investigations. These techniques transformed an invisible defect into a visible one, leading to a full resolution of the issue with good understanding of the failure mechanism and the root cause. We will show that the wafer edge leakage was the result of N-type contamination of the substrate due to Phosphorus outgassing from the V-ring during the high temperature Argon anneal process.

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Song, Zhigang, Pat McGinnis, Dave Albert, Greg Hornicek, Mike Tenney, Larry Fischer, John Sylvestri, et al. "Electrical Probing Role in 14nm SOI Microprocessor Failure Analysis." In ISTFA 2020. ASM International, 2020. http://dx.doi.org/10.31399/asm.cp.istfa2020p0061.

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Abstract Failure analysis plays a very important role in semiconductor industry. Photon Emission Microscopy (PEM) has been extensively used in localization of fails in microelectronic devices. However, PEM emission site is not necessarily at the location of the defect. Thus, it has limitation for the success rate of the follow-up physical failure analysis focusing on the emission site. As semiconductor technology advanced in the 3D FinFET realm and feature size further shrank down, the invisible defects during SEM inspection are tremendously increased. It leads to the success rate further decreasing. To maintain good success rate of failure analysis for advanced 3D FinFET technology, electrical probing is necessary to be incorporated into the failure analysis flow. In this paper, first, the statistic results of PEM emission sites versus real defect locations from 102 modules of microprocessors manufactured by 14nm 3D FinFET technology was present. Then, we will present how to wisely design electrical probing plan after PEM analysis. The electrical probing plans are tailored to different scan chain and ATPG failures of microprocessors for improving failure analysis success rate without increasing too much turn-around time. Finally, two case studies have been described to demonstrate how the electrical probing results guide the follow-up physical failure analysis to find the defect.

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Syngaevsky, Pavel E. "Tectonic and Overpressured Zones, Gulf of Mexico." In ASME 2001 Engineering Technology Conference on Energy. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/etce2001-17172.

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Abstract We observe two different events happening in a Matagorda Island area. Faults may act as a seal and enhance the shale sealing. Changes in pore pressure calculated from sonic/resistivity logs are steep, “transitional” zone is about a 100–150′ thick and almost invisible at a whole well scale. Because of such sharp changes these zones are hard to recognize on MWD, however typically one casing point required to separate it from upper normally pressured section. Another option — fault causes partial damage, possibly through micro-fractures in shales. Shale sealing properties are decreased pore pressure in reservoir sands is lower, that in neighboring blocks. Sealing zone possess gradual changes in pore pressure with lower values that expected. Such zones are up to 2000′ thick and could be observed on MWD as well as on conventional log diagrams. Several casing points required in order to drill through such zone. By incorporating this information into the geological model one can predict whether the fault will act as a pressure-formation liquids “semi-conductor” or as a good seal. Faults that damage the seal above overpressured zone might result in unexpected shallow overpressure and/or shallow gas. Such faults should be determined, mapped and avoid when possible from drilling.

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Hersberger, Carsten, Elias Waldvogel, Joshua Bopp, and Beat Ribi. "Design of an Innovative Moisture Separator Technology for Use in Nuclear Power Plants: Experimental Validation — Part 2." In 2020 International Conference on Nuclear Engineering collocated with the ASME 2020 Power Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/icone2020-16550.

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Abstract The Moisture Separator Reheater (MSR) is a key component of Nuclear Power Plants (NPP), both in terms of performance and prevention of erosion/corrosion. Wet steam is usually dried in a MSR by inertial separation of the liquid water using separator elements. Depending on the design of the MSR, the technology of the separator elements contributes significantly to its size and performance. An innovative concept of separator panels was conceived by means of aerodynamic principles as outlined in part 1 of this paper [1]. Computational Fluid Dynamics (CFD) has been used to understand the working principles of various moisture separating devices. The investigated separator panels are designed to capture the water droplets in a region of flow separation (invisible pockets) within the separator channels. To characterize the separation performance of these separator panels, a test rig has been developed and built at the University of Applied Sciences Northwestern Switzerland (FHNW). This test rig was then operated at typical MSR operating conditions. To meet the required moisture content and flow conditions, preheated water was injected into the saturated steam flow. In order to measure the residual moisture content after the separation the throttling calorimeter methodology has been adopted. The newly designed panels have shown very good separation performance. According to the measurements carried out, a residual moisture content of less than 0.1 % can be guaranteed. The innovative technology, which clearly differentiates the OEM, for who this research was carried out, from its competitors, will allow considerable size and cost reduction as well as opportunities to retrofit existing MSRs.

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Reports on the topic "Invisible gold"

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Pinet, N., O. H. Ardakani, J. Cesar, D. C. Petts, C. Debuhr, and P J Sack. Exploring the link between organic matter and Carlin-type gold mineralization: new insights from Yukon deposits. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/330086.

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The link between organic matter and gold in sediment-hosted Carlin-type deposits is controversial. This study aims to tackle this potential link by documenting the occurrence of organic matter in a single borehole from a Carlin-type gold deposit in Yukon and by considering, in a preliminary way, the spatial and/or temporal relationship between organic matter and gold mineralization. The sedimentary succession hosting the Conrad deposit was relatively rich in organic matter, possibly related to Archea. Despite the high maturation of samples, the total organic carbon (TOC) content of the limestone unit averages 1.31 wt. % (maximum = 3.18 wt. %). Petrographic observations indicate that pore and fracture filling pyrobitumen is the dominant organic matter maceral in the studied samples. This type of pyrobitumen was matured after its emplacement, indicating that hydrocarbon fluids cannot have served as an agent for gold transport. Pyrobitumen disseminated in the rock or associated with stylolites are also documented. The correlation between TOC and Tl (the best proxy for Au) for selected samples and the high As content of pyrobitumen filling pores may suggest a link between organic matter content and gold deposition, but this was not demonstrated by LA-ICP-MS micro-scale mapping. This study also highlights the challenges of establishing a direct spatial relationship between 'invisible' gold and very small (&lt; 10 µm) pyrobitumen particles.

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Gaynor, Martin, Deborah Haas-Wilson, and William Vogt. Are Invisible Hands Good Hands? Moral Hazard, Competition, and the Second Best in Health Care Markets. Cambridge, MA: National Bureau of Economic Research, December 1998. http://dx.doi.org/10.3386/w6865.

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Astudillo, Karen, Vicente Fretes Cibils, Carola Pessino, and Darío Rossignolo. Making the Invisible Visible: Applying a Gender Perspective To Strengthen Tax Policy in Latin America and the Caribbean. Inter-American Development Bank, July 2022. http://dx.doi.org/10.18235/0004350.

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Latin American and Caribbean countries have made efforts to ensure that fiscal policies do not cause biases toward women. However, depending on where the tax burden falls, taxes do create gender biases. This technical note has two purposes. First, it provides evidence of how womens economic participation, care responsibilities, and consumption patterns enter into a countrys tax systems, generating invisible biases. Second, it summarizes the main lessons learned through cross-country comparisons that analyze the impact of direct and indirect taxes on gender equality, the progressivity of the tax systems using both income and expenditure as welfare measures, and the impact of tax systems and tax reforms on households depending on their composition and across the income distribution. The note also provides policy recommendations and good practices that will add to the regions efforts to strengthen fiscal policy taking a gender perspective into account. There is no unique approach to achieving gender equity only through gender-sensitive fiscal policies; rather, the path to change will likely be highly dependent on the balance struck between differing political and economic factors and interests. However, should Latin American and the Caribbean countries take on this challenge, not only could they generate more revenue in the future, but the changes should contribute to sustained and inclusive growth, with greater gender equality.

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