scholarly journals Mobility of black carbon in drained peatland soils

2007 ◽  
Vol 4 (2) ◽  
pp. 871-891 ◽  
Author(s):  
J. Leifeld ◽  
S. Fenner ◽  
M. Müller
Keyword(s):  
Thermal Oxidation ◽  
Black Carbon ◽  
Water Saturation ◽  
High Mobility ◽  
Organic Soil ◽  
Historical Record ◽  
Scanning Calorimetry ◽  
Different Types ◽  
Ploughing Depth ◽  
Combustion Residues

Abstract. Amount, stability, and distribution of black carbon BC were studied at four sites of a large peatland ("Witzwil") formerly used as a disposal for combustion residues from households to derive BC displacement rates in the profile. Possible artefacts from thermal oxidation with Differential Scanning Calorimetry (DSC) on BC quantification of C-rich deposits were inferred by choosing three sites from a second peatland with no historical record of waste disposal as a reference ("Seebodenalp"). All sites were under grassland at time of sampling, but were partially cropped in the past at Witzwil. Mean BC contents in topsoils of Witzwil ranged from 10.7 to 91.5 (0–30 cm) and from 0.44 to 51.3 (30–140 cm) mg BC g−1 soil, corresponding to BC/OC ratios of 0.04 to 0.3 (topsoil) and 0.02 to 0.18 (deeper soil). At three sites of Seebodenalp, BC was below the detection limit of 0.4 mg g−1 organic soil, indicating negligible formation of BC during thermal oxidation of peat. 13C NMR spectra corroborated the high BC contents at Witzwil. The data refer to a considerable vertical transport of BC given that soils were ploughed not deeper than 30 cm since abandonment of waste application about 50 years ago. The total amount of BC in the Witzwil profiles ranged from 3.2 to 7.5 kg BC m−2, with 21 to 69 percent of it stemming from below the former ploughing depth. Under the premise of negligible rates of BC consumption since abandonment of waste application, minimum BC transport rates in these peats are 0.6 to 1.2 cm a−1. The high mobility of BC might be explained by high macro-pore volumes in combination with occasional water saturation. By means of DSC peak temperatures, different types of BC could be distinguished, with deeper horizons containing BC of higher thermal stability. Application of combustion residues likely involved a mixture of various BC types, of which thermally more stable ones, most likely soots, were preferentially transported downwards.

scholarly journals Mobility of black carbon in drained peatland soils

2007 ◽  
Vol 4 (3) ◽  
pp. 425-432 ◽  
Author(s):  
J. Leifeld ◽  
S. Fenner ◽  
M. Müller
Keyword(s):  
Thermal Oxidation ◽  
Black Carbon ◽  
Water Saturation ◽  
High Mobility ◽  
Organic Soil ◽  
Historical Record ◽  
Scanning Calorimetry ◽  
Different Types ◽  
Ploughing Depth ◽  
Combustion Residues

Abstract. Amount, stability, and distribution of black carbon (BC) were studied at four sites of a large peatland ("Witzwil") formerly used as a disposal for combustion residues from households to derive BC displacement rates in the profile. Possible artefacts from thermal oxidation with Differential Scanning Calorimetry (DSC) on BC quantification of C-rich deposits were inferred by choosing three sites from a second peatland with no historical record of waste disposal as a reference ("Seebodenalp"). All sites were under grassland at time of sampling, but were partially cropped in the past at Witzwil. Mean BC contents in topsoils of Witzwil ranged from 10.7 to 91.5 (0–30 cm) and from 0.44 to 51.3 (30–140 cm) mg BC g−1 soil, corresponding to BC/OC ratios of 0.04 to 0.3 (topsoil) and 0.02 to 0.18 (deeper soil). At three sites of Seebodenalp, BC was below the detection limit of 0.4 mg g−1 organic soil, indicating negligible formation of BC during thermal oxidation of peat. 13C NMR spectra corroborated the high BC contents at Witzwil. The data support a considerable vertical transport of BC given that soils were ploughed not deeper than 30 cm since abandonment of waste application about 50 years ago. The total amount of BC in the Witzwil profiles ranged from 3.2 to 7.5 kg BC m−2, with 21 to 69 percent of it stemming from below the former ploughing depth. Under the premise of negligible rates of BC consumption since abandonment of waste application, minimum BC transport rates in these peats are 0.6 to 1.2 cm a−1. The high mobility of BC might be explained by high macro-pore volumes in combination with occasional water saturation. By means of DSC peak temperatures, different types of BC could be distinguished, with deeper horizons containing BC of higher thermal stability. Application of combustion residues likely involved a mixture of various BC types, of which thermally more stable ones, most likely soots, were preferentially transported downwards.

A TEM study of the effect of oxygen on nanocavity formation and precipitation in rapid - solidified Fe-16Ni-9Cr stainless steels

1994 ◽  
Vol 52 ◽  
pp. 700-701
Author(s):  
S. Wisutmethangoon ◽  
T. F. Kelly ◽  
J.E. Flinn
Keyword(s):  
Stainless Steels ◽  
High Mobility ◽  
Hot Extrusion ◽  
Extrusion Ratio ◽  
Gas Atomization ◽  
Cavity Formation ◽  
Nucleation Sites ◽  
Heat Treated ◽  
Different Types ◽  
Effect Of Oxygen

Vacancies are introduced into the crystal phase during quenching of rapid solidified materials. Cavity formation occurs because of the coalescence of the vacancies into a cluster. However, because of the high mobility of vacancies at high temperature, most of them will diffuse back into the liquid phase, and some will be lost to defects such as dislocations. Oxygen is known to stabilize cavities by decreasing the surface energy through a chemisorption process. These stabilized cavities, furthermore, act as effective nucleation sites for precipitates to form during aging. Four different types of powders with different oxygen contents were prepared by gas atomization processing. The atomized powders were then consolidated by hot extrusion at 900 °C with an extrusion ratio 10,5:1. After consolidation, specimens were heat treated at 1000 °C for 1 hr followed by water quenching. Finally, the specimens were aged at 600 °C for about 800 hrs. TEM samples were prepared from the gripends of tensile specimens of both unaged and aged alloys.

Fabrication of Strain Relaxed Silicon-Germanium-on-Insulator (Si0.35Ge0.65OI) Wafers using Cyclical Thermal Oxidation and Annealing

2007 ◽  
Vol 994 ◽  
Author(s):  
Grace Huiqi Wang ◽  
Eng-Huat Toh ◽  
Chih-Hang Tung ◽  
Yong-Lim Foo ◽  
S. Tripathy ◽  
...  
Keyword(s):  
Thermal Oxidation ◽  
Mole Fraction ◽  
Systematic Study ◽  
Silicon Germanium ◽  
High Mobility ◽  
Sige Layer ◽  
Strain Engineering ◽  
Surface Roughening ◽  
Clear Understanding ◽  
Strain Evolution

AbstractA novel scheme for the fabrication of SiGe-on-insulator (SGOI) substrates comprising a thin and relaxed silicon-germanium (SiGe) layer with high Ge mole fraction is reported. A cyclical thermal oxidation and annealing (CTOA) process is introduced to alleviate issues associated with surface roughening and non-uniformity in Ge content. A systematic study of the stress developed in the SiGe layer as condensation takes place is presented. A clear understanding of the strain evolution enables the SGOI substrate fabrication to be tailored according to the requirements of strain engineering in high mobility MOSFETs.

Comparative study on the mechanical, tribological, and thermal properties of POM composites filled with different PTFE

2020 ◽  
pp. 089270572093262
Author(s):  
Hao Zhang ◽  
Yue Wu ◽  
Mei Liang ◽  
Hang Wu ◽  
Huawei Zou ◽  
...  
Keyword(s):  
Wear Rate ◽  
Tribological Properties ◽  
Load Transfer ◽  
Filler Concentration ◽  
Scanning Calorimetry ◽  
Ptfe Particle ◽  
Different Types ◽  
Pin On Disc ◽  
Ptfe Composites ◽  
The Impact

In this study, two different types of polytetrafluoroethylene (PTFE) fillers (i.e. fibrillar and particulate PTFE) were utilized to improve the tribological properties of polyoxymethylene (POM). POM/PTFE composites with various filler contents were tested on a commercial block-on-ring tester. To further probe the tribological properties of POM/PTFE composites under severe sliding conditions, a homemade pin-on-disc tester was employed. Results showed that the lowest coefficient of friction and wear rate are obtained from PTFE particle–filled POM composites at 20 wt%, which is attributed to the formation of uniform transfer film at the sliding interface thanks to the well distribution of PTFE particles. The mass wear rate of POM/PTFE fiber composites is lower than that of PTFE particle–containing counterparts due to the better load transfer of high aspect ratio fibers. The tensile properties of POM/PTFE composites deteriorate with the addition of PTFE fillers; however, the impact strength is significantly enhanced for PTFE fiber filled POM composites. Moreover, both the melting and crystallization properties of POM are affected by the morphology of PTFE fillers and filler concentration, as characterized by differential scanning calorimetry analysis.

scholarly journals In Vitro Corrosion Behavior of Lingual Orthodontic Archwires

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Carlos Suárez ◽  
Teresa Vilar ◽  
Pablo Sevilla ◽  
Javier Gil
Keyword(s):  
Differential Scanning Calorimetry ◽  
Stainless Steel ◽  
Rhombohedral Phase ◽  
Nickel Titanium ◽  
Scanning Calorimetry ◽  
Lingual Orthodontics ◽  
Phase Transition Temperatures ◽  
Different Types ◽  
Orthodontic Archwires

Objectives. To investigate the in vitro electrochemical corrosive behavior of archwires used in lingual orthodontics and the effects on the phase transition temperatures.Materials and Methods. Six different types of archwires of stainless steel, titanium-molybdenum, nickel-titanium and nickel-titanium-copper were used. Corrosion tests were performed following ISO-standard 10993-15:2000. Differential scanning calorimetry and scanning electron microscopy were used.Results. The stainless steel archwires showed anEpitaround −600 mV, and those of titanium alloys showedEpitvalues around 1000 mV. Differential scanning calorimetry detected a rhombohedral phase in nickel-titanium archwires, while it was not detected in nickel-titanium-copper wires. A difference of 2°C to 3.5°C from the manufacturer's claim was found in the as-received and polarized samples, respectively.Conclusions. The 0.016 stainless steel archwires were found to be the less resistant to corrosion. A rhombohedral phase was detected on the nickel-titanium archwires. No major differences were observed among groups concerning phase transformation temperatures.

scholarly journals Black carbon record based on a shallow Himalayan ice core and its climatic implications

2007 ◽  
Vol 7 (5) ◽  
pp. 14413-14432 ◽  
Author(s):  
J. Ming ◽  
H. Cachier ◽  
C. Xiao ◽  
D. Qin ◽  
S. Kang ◽  
...  
Keyword(s):  
Black Carbon ◽  
Trajectory Analysis ◽  
Continuous Measurement ◽  
Ice Core ◽  
Historical Record ◽  
The Tibetan Plateau ◽  
The Past ◽  
Increasing Trend ◽  
Radiative Absorption ◽  
Air Trajectory

Abstract. A continuous measurement for black carbon conducted on a shallow ice core extracted from the East Rongbuk glacier beside Mt. Qomolangma recovers the first historical record of black carbon 13 deposition in the past ~50 years in the high Asian cryosphere. Fast increasing trend of BC concentration is revealed since the mid-1990s. Backward air trajectory analysis indicates that South Asia's emission has significant impacts on the BC deposition in the East Rongbuk glacier. The estimated atmospheric BC concentration over the East Rongbuk glacier is about 80 ngC m−3. This suggests black carbon from South Asia's emission might penetrate into the Tibetan Plateau by 18 climbing over the elevated Himalayas. Considering the consequent extra solar radiative absorption over the glacier, it is suggested that this amplitude of BC concentration in the atmosphere over the Himalayas could not be neglected when assessing the warming effect on the surface of the glaciers on the Himalayas.

scholarly journals Information Characteristics for Judicative Documentation of the end the 18th – beginning of the 19th centuries for the Investigation of the History of Everyday Life in the Southern Ukraine

2020 ◽  
Vol 2 (1) ◽  
pp. 149
Author(s):  
Olha M. Posunko
Keyword(s):  
Everyday Life ◽  
Social History ◽  
High Mobility ◽  
Judicial System ◽  
District Court ◽  
Short Period ◽  
Different Types ◽  
History Of ◽  
Information Characteristics ◽  
Southern Ukraine

Social history (the history of everyday life) is a popular trend in modern Ukrainian historical studies. At the same time, it should be noted the studies aimed at the research of everyday life, life, stereotypes, incidents, personal life have an integrated nature. The proposed topic covers a short period of time, which was due to the introduction in the territory of Southern Ukraine of a new judicial system in accordance with the Provisions on Provinces of 1775. Thus, the judicial instances of Yekaterinoslav governorship (1783–1796), later of the Novorossiysk province (1796–1802) are under review. The region is vast, heterogeneous in various indicators. The purpose of the article is to determine the characteristics of different types of forensic documentation, which have the greatest information potential in studying the problems of everyday life of people of the late XVIII – early XIX centuries. The source base are the materials of judicial institutions of the region, ranging from the county level (district courts, magistrates, reprisals) to provincial ones (high district court, high reprisal, provincial magistrate, conscientious court, court chamber and reprisals). The task is to characterize the different types of sources used to disclose the topic; to highlight the scenes that are most clearly presented in these documents. The main results. Characteristics of the following types of court documentation are given: journals (meetings, minutes, decisions); property registries; petitions; interrogations; extracts of cases. As an exception, personal letters are mentioned that were used as evidence at courts. The methods of hermeneutics are of great importance, since due to the lack of other sources, clearly formulated questions and a careful reading of the available documents for the formation of ideas about the era are crucially important. It has been noted that the functioning of the judicial system itself provides facts for the study of the stated topic. According to the approaches of the German sociologist N. Elias in the history of everyday life such category as "working day" is considered. It was at a specified time that the bureaucratic apparatus of the region was emerging with a new bureaucracy and its work schedule, which set a certain rhythm of the life of county and provincial cities. The conclusion is made about the possibility of studying, clarifying individual plots on the history of everyday life of almost all segments of the population (to a lesser extent, peasants). It is noted that criminal cases have a wider social variety. The life of the nobility is characterized primarily by documents of civil proceedings (inheritance division, disputes over land). They demonstrate the household side in the process of distribution and delimitation of land, which Southern Ukraine was experiencing during this period. There are two traditions at the cultural and legal levels: one appeals to the norms of the Lithuanian Statute of 1588 (in counties that have moved away from the territory of the former Hetmanate), the other to Russian imperial legislation. The documents of the judicial instances of the region confirm the fact of quite a high mobility of the population within southern Ukraine; point at the development of modern processes (including their negative manifestations in the form of rising crime); allow us to see the ugly side of the daily life of an individual at that time. Article type: analytical.

scholarly journals Geoelectrical and Geotechnical Characterization of Different Types of Soil in Ede, Osun State, Nigeria

2021 ◽  
Vol 6 (2) ◽  
Author(s):  
Wilfred N. Igboama ◽  
Olaide S. Hammed ◽  
Maruf T. Aroyehun ◽  
Nicholas U. Ugwu
Keyword(s):  
Organic Soil ◽  
Electrode Spacing ◽  
Dry Density ◽  
Sieve Analysis ◽  
Maximum Dry Density ◽  
Geotechnical Investigations ◽  
Different Types ◽  
Geoelectrical Resistivity ◽  
Wenner Array

Geoelectrical and geotechnical investigations were carried out to characterize soils from different locations in Ede, Osun State, Nigeria for engineering purposes. Wenner electrode configuration technique was deployed in carrying out the geoelectrical survey of about 40m for each profile. The data analysis was approached by plotting the apparent conductivity against electrode spacing (s) and the result was interpreted.  The geoelectrical resistivity survey revealed locations 1 and 2 with resistivity values of 25.01-419.22ohm-m (conductivity 0.002 - 0.194 (ohm-m)-1and 5.5-1246.57 ohm-m (conductivity = 0.0002 - 0.001 (ohm-m)-1) respectively could be classified as clay. Sample 3 recorded a resistivity value of 1.00- 22,787.39 ohm-m (conductivity= 0.00004- 1.00 (ohm-m)-1) thus, was classified as silt/sand respectively. Soil  from the said different locations in Ede, Nigeria, were tested in the Laboratory for certain properties like Atterberg limits, specific gravities, sieve analysis, compaction test, etc and the results showed that samples 1, 2 and 3 have specific gravity values of 2.50, 2.13 and 2.40 respectively and could therefore be referred to as organic soil. Samples 1, 2 and 3 have maximum dry density (MDD) of 1.45g/cm3­, 1.92g/cm3, 1.95g/cm3 and optimum moisture content (OMC) of 15.40%, 13.36% and 9.61% respectively. The analysis conducted in this study revealed that the soil type found in Ede, Nigeria could be classified as silt-clay, sandy clay, clay and sand.Keywords- Electrical conductivity, Characterization, Compaction, Plasticity, Wenner array.

scholarly journals On Long-Term Stability of Metallic Glasses

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1076 ◽  
Author(s):  
Louzguine-Luzgin ◽  
Jiang
Keyword(s):  
Metallic Glasses ◽  
Surface Oxidation ◽  
Initial Structure ◽  
Ambient Conditions ◽  
Scanning Calorimetry ◽  
Long Term Stability ◽  
Transmission Electron ◽  
Different Types ◽  
Thermal Stability Of

Thermal stability of different types of metallic glasses and partially crystalline alloys stored for at least 15 years at ambient conditions was tested in the present work by differential scanning calorimetry in comparison with that of the original alloys tested in the as-cast state in the earlier works. The structure of the naturally aged alloys was also studied by X-ray diffractometry. The structure of a couple of selected alloys was also tested by transmission electron microscopy. Most of the alloys retained their initial structure and showed only a moderate decrease in the crystallization temperature. Only those alloys which showed visible surface oxidation (Cu-Zr-system based) were partly transformed into a crystalline state forming micron-scale Cu particles in air at ambient conditions.

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