Pompeii AD 79: A Natural Bone Diagenesis Experiment

Radiocarbon ◽  
2016 ◽  
Vol 59 (2) ◽  
pp. 647-658 ◽  
Author(s):  
Antoine Zazzo ◽  
Sébastien Lepetz
Keyword(s):  
Carbon Content ◽  
Large Deviation ◽  
Campi Flegrei ◽  
Absolute Amount ◽  
Low Carbon ◽  
Volcanic System ◽  
Natural Bone ◽  
Different Types ◽  
Bone Diagenesis ◽  
Burnt Bone

AbstractThis study aims at comparing the reliability of different types of apatite fractions for which collagen cannot be dated. We focused on the remains of individuals found at the necropolis of Porta Nocera near Pompeii, and for which the date of burial can be assessed independently. The dated human samples range between 1805±49 and 5570±120 14C yr BP and can display a large (up to 1200 14C yr) intra-individual age variability. We show that while a marine diet or an old-wood effect could explain the smallest age shifts, they are not able to explain the largest ones, and propose diagenesis as the main cause. The 14C depletion is likely due to the influence of the 14C-free CO2 emissions of the nearby Vesuvius volcano and the Campi Flegrei volcanic system on the age of secondary carbonate incorporated into the bone and enamel crystallites during diagenesis. This study demonstrates that in volcanic contexts, a large deviation from expected age can be measured, even in calcined apatites. Our calculations indicate that while the absolute amount of contamination is lower in calcined bones than in burnt bone and enamel apatite, its impact on the 14C age of the sample can be much higher due to the low carbon content of calcined bones.

EASTERN STAINLESS TYPE 316L

Alloy Digest ◽  
1984 ◽  
Vol 33 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Carbon Content ◽  
Heat Treating ◽  
Low Carbon ◽  
Steel Company ◽  
Aisi Type ◽  
Type 316L ◽  
Molybdenum Steel

Abstract EASTERN STAINLESS Type 316L is a chromium-nickel-molybdenum steel with a very low carbon content (0.03 max.) Its general resistance to corrosion is similar to AISI Type 316 but, because of its low carbon content, it has superior resistance to the formation of harmful carbides that contribute to intergranular corrosion. Type 316L is used widely in many industries such as chemical, food, paper, textile, nuclear and oil. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-439. Producer or source: Eastern Stainless Steel Company.

EASTERN STAINLESS TYPE 304L

Alloy Digest ◽  
1983 ◽  
Vol 32 (6) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Shear Strength ◽  
Carbon Content ◽  
Heat Treating ◽  
Low Carbon ◽  
Steel Company ◽  
Aisi Type ◽  
Type 304

Abstract EASTERN STAINLESS TYPE 304L is the basic 18-8 chromium-nickel austenitic stainless steel with a very low carbon content (0.03% max.). Its general resistance to corrosion is similar to AISI Type 304 but, because of its low carbon content, it has superior resistance to the formation of harmful carbides that indirectly contribute to intergranular corrosion. It is recommended for most articles of welded construction. Postweld annealing is not necessary. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-427. Producer or source: Eastern Stainless Steel Company.

scholarly journals Low-carbon cast microalloyed steel intercritically heat-treated at different temperatures: microstructure and mechanical properties

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Hadi Torkamani ◽  
Shahram Raygan ◽  
Carlos Garcia Mateo ◽  
Yahya Palizdar ◽  
Jafar Rassizadehghani ◽  
...  
Keyword(s):  
Carbon Content ◽  
Volume Fraction ◽  
Block Size ◽  
Tensile Tests ◽  
Total Elongation ◽  
Martensite Phase ◽  
Low Carbon ◽  
Steel Increase ◽  
Different Temperatures ◽  
The Impact

AbstractIn this study, dual-phase (DP, ferrite + martensite) microstructures were obtained by performing intercritical heat treatments (IHT) at 750 and 800 °C followed by quenching. Decreasing the IHT temperature from 800 to 750 °C leads to: (i) a decrease in the volume fraction of austenite (martensite after quenching) from 0.68 to 0.36; (ii) ~ 100 °C decrease in martensite start temperature (Ms), mainly due to the higher carbon content of austenite and its smaller grains at 750 °C; (iii) a reduction in the block size of martensite from 1.9 to 1.2 μm as measured by EBSD. Having a higher carbon content and a finer block size, the localized microhardness of martensite islands increases from 380 HV (800 °C) to 504 HV (750 °C). Moreover, despite the different volume fractions of martensite obtained in DP microstructures, the hardness of the steels remained unchanged by changing the IHT temperature (~ 234 to 238 HV). Applying lower IHT temperature (lower fraction of martensite), the impact energy even decreased from 12 to 9 J due to the brittleness of the martensite phase. The results of the tensile tests indicate that by increasing the IHT temperature, the yield and ultimate tensile strengths of the DP steel increase from 493 to 770 MPa, and from 908 to 1080 MPa, respectively, while the total elongation decreases from 9.8 to 4.5%. In contrast to the normalized sample, formation of martensite in the DP steels could eliminate the yield point phenomenon in the tensile curves, as it generates free dislocations in adjacent ferrite.

scholarly journals Does the Opening of High-Speed Railway Lines Reduce the Carbon Intensity of China’s Resource-Based Cities?

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4648
Author(s):  
Zhipeng Tang ◽  
Ziao Mei ◽  
Jialing Zou
Keyword(s):  
High Speed ◽  
National Average ◽  
Carbon Intensity ◽  
Time Varying ◽  
Low Carbon ◽  
High Speed Railway ◽  
Different Types ◽  
Endogenous Selection ◽  
Mode Of Development ◽  
The Impact

The carbon intensity of China’s resource-based cities (RBCs) is much higher than the national average due to their relatively intensive mode of development. Low carbon transformation of RBCs is an important way to achieve the goal of reaching the carbon emissions peak in 2030. Based on the panel data from 116 RBCs in China from 2003 to 2018, this study takes the opening of high-speed railway (HSR) lines as a quasi-experiment, using a time-varying difference-in-difference (DID) model to empirically evaluate the impact of an HSR line on reducing the carbon intensity of RBCs. The results show that the opening of an HSR line can reduce the carbon intensity of RBCs, and this was still true after considering the possibility of problems with endogenous selection bias and after applying the relevant robustness tests. The opening of an HSR line is found to have a significant reducing effect on the carbon intensity of different types of RBC, and the decline in the carbon intensity of coal-based cities is found to be the greatest. Promoting migration of RBCs with HSR lines is found to be an effective intermediary way of reducing their carbon intensity.

Shape-Tailored TiO2 Photocatalysts Obtained in the Presence of Different Types of Carbon Materials

2021 ◽  
Vol 21 (4) ◽  
pp. 2360-2367
Author(s):  
Krisztina Vajda ◽  
Klára Hernádi ◽  
Cosmin Coteţ ◽  
Gábor Kovács ◽  
Zsolt Pap
Keyword(s):  
Carbon Materials ◽  
Uv Light ◽  
Carbon Aerogel ◽  
Low Carbon ◽  
Negative Effects ◽  
Tio2 Photocatalysts ◽  
Uv Light Irradiation ◽  
Specific Morphology ◽  
Different Types ◽  
Photocatalytic Applications

Titania and carbon materials are intensively studied in composite materials including photocatalytic applications. Both positive and negative effects were described in the literature, including charge separation, adsorption enhancement and short-circuiting of the photoelectrons as well. In the present study a more sparsely investigated properties of carbon materials will be highlighted, namely their role as crystallization promoters for titania, during hydrothermal synthesis of the composites. Therefore, carbon nanotubes, carbon coils, activated carbon, graphite and carbon aerogel was used to identify the importance of carbon during the time dependent crystallization of titanium dioxide. The crystal phase composition, morphology, optical properties and photocatalytic activity was followed, and it was found that the anatase and rutile crystallization depended on the used carbon material. The morphology of the particles varied from single anatase sheet-like crystals to hierarchical microball-like structures, while in some cases no specific morphology was observed. Furthermore, it was found that despite the low carbon content (2 wt.%) and microcrystalline structure of TiO2 the composites were proven to be efficient in the degradation of Rhodamine B under UV light irradiation.

Effect of Soaking Time on Paste Carburizing of Carburized Low Carbon Steel

2017 ◽  
Vol 740 ◽  
pp. 93-99
Author(s):  
Muhammad Hafizuddin Jumadin ◽  
Bulan Abdullah ◽  
Muhammad Hussain Ismail ◽  
Siti Khadijah Alias ◽  
Samsiah Ahmad
Keyword(s):  
Carbon Steel ◽  
Carbon Content ◽  
Low Carbon Steel ◽  
Case Depth ◽  
Carbon Steels ◽  
Low Carbon ◽  
Soaking Time ◽  
Low Carbon Steels ◽  
Carburized Steel ◽  
Carburizing Process

Increase of soaking time contributed to the effectiveness of case depth formation, hardness properties and carbon content of carburized steel. This paper investigates the effect of different soaking time (7-9 hours) using powder and paste compound to the carburized steel. Low carbon steels were carburized using powder and paste compound for 7, 8 and 9 hours at temperature 1000°C. The transformation of microstructure and formation carbon rich layer was observed under microscope. The microhardness profiles were analyzed to investigate the length of case depth produced after the carburizing process. The increment of carbon content was considered to find the correlation between types of carburizing compound with time. Results shows that the longer carburized steel was soaked, the higher potential in formation of carbon rich layer, case depth and carbon content, which led to better hardness properties for carburized low carbon steel. Longer soaking time, 9 hours has a higher dispersion of carbon up to 41%-51% compare to 8 hours and 7 hours. By using paste carburizing, it has more potential of carbon atom to merge the microstructure to transform into cementite (1.53 wt% C) compare to powder (0.97 wt% C), which increases the hardness of carburized steel (13% higher).

scholarly journals Low carbon content NiTi shape memory alloy produced by electron beam melting

2004 ◽  
Vol 7 (2) ◽  
pp. 263-267 ◽  
Author(s):  
Jorge Otubo ◽  
Odair Doná Rigo ◽  
Carlos de Moura Neto ◽  
Michael Joseph Kaufman ◽  
Paulo Roberto Mei
Keyword(s):  
Electron Beam ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Carbon Content ◽  
Electron Beam Melting ◽  
Niti Shape Memory Alloy ◽  
Low Carbon

Structural Properties of a-Ge1-xCx:H Alloys Prepared by the RF Sputtering Technique

1997 ◽  
Vol 467 ◽  
Author(s):  
F. C. Marques ◽  
J. Vilcarromero ◽  
F. L. Freire
Keyword(s):  
Carbon Content ◽  
Rf Sputtering ◽  
Low Carbon ◽  
Infrared Transmission ◽  
Absorption Bands ◽  
Optical Gap ◽  
High Carbon Concentration ◽  
Bending Modes ◽  
Hydrogenated Amorphous ◽  
Hydrogenated Amorphous Germanium

ABSTRACTStructural and mechanical properties of hydrogenated amorphous germanium carbon (a-Ge1-xCx:H) alloys are presented. The films were prepared by the rf-co-sputtering technique using a graphite/germanium composed target. The carbon and germanium relative concentrations were determined by RBS, and the total hydrogen concentration by ERDA measurements. An increase in the optical gap was measured for low carbon content (0 < × < 0.15). For higher values of x the optical gap is almost constant. Infrared transmission absorption spectra show several absorption bands related to Ge-C stretching, C-Hn (n = 1,2,3) and Ge-H stretching and bending modes. The mechanical internal stress was strongly affected by the incorporation of carbon. The trends of the optical gap, refractive index, infrared absorption and mechanical stress as a function of the carbon content suggest that the high carbon concentration alloys have polymeric and/or graphite-like contribution in their structure.

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