scholarly journals Coring of Antarctic Subglacial Sediments

2019 ◽  
Vol 7 (6) ◽  
pp. 194 ◽  
Author(s):  
Gong ◽  
Fan ◽  
Li ◽  
Li ◽  
Zhang ◽  
...  

Coring sediments in subglacial aquatic environments offers unique opportunities for research on paleo-environments and paleo-climates because it can provide data from periods even earlier than ice cores, as well as the overlying ice histories, interactions between ice and the water system, life forms in extreme habitats, sedimentology, and stratigraphy. However, retrieving sediment cores from a subglacial environment faces more difficulties than sediment coring in oceans and lakes, resulting in low yields from the most current subglacial sediment coring methods. The coring tools should pass through a hot water-drilled access borehole, then the water column, to reach the sediment layers. The access boreholes are size-limited by the hot water drilling tools and techniques. These holes are drilled through ice up to 3000–4000 m thick, with diameters ranging from 10–60 cm, and with a refreezing closure rate of up to 6 mm/h after being drilled. Several purpose-built streamline corers have been developed to pass through access boreholes and collect the sediment core. The main coring objectives are as follows: (i) To obtain undisturbed water–sediment cores, either singly or as multi-cores and (ii) to obtain long cores with minimal stratigraphic deformation. Subglacial sediment coring methods use similar tools to those used in lake and ocean coring. These methods include the following: Gravity coring, push coring, piston coring, hammer or percussion coring, vibrocoring, and composite methods. Several core length records have been attained by different coring methods, including a 290 cm percussion core from the sub-ice-shelf seafloor, a 400 cm piston core from the sub-ice-stream, and a 170 cm gravity core from a subglacial lake. There are also several undisturbed water–sediment cores that have been obtained by gravity corers or hammer corers. Most current coring tools are deployed by winch and cable facilities on the ice surface. There are three main limitations for obtaining long sediment cores which determines coring tool development, as follows: Hot-water borehole radial size restriction, the sedimentary structure, and the coring techniques. In this paper, we provide a general view on current developments in coring tools, including the working principles, corer characteristics, operational methods, coring site locations, field conditions, coring results, and possible technical improvements. Future prospects in corer design and development are also discussed.

HortScience ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 249a-249
Author(s):  
Eric A. Lavoie ◽  
Damien de Halleux ◽  
André Gosselin ◽  
Jean-Claude Dufour

The main objective of this research was to produce a simulated model that permitted the evaluation of operating costs of commercial greenhouse tomato growers with respect to heating methods (hot air, hot water, radiant and heat pumps) and the use of artificial lighting for 1991 and 1992. This research showed that the main factors that negatively influence profitability were energy consumption during cold periods and the price of tomatoes during the summer season. The conventional hot water system consumed less energy than the heat pump system and produced marketable fruit yields similar to those from the heat pump system. The hot water system was generally more profitable in regards to energy consumption and productivity. Moreover, investment costs were less; therefore, this system gives best overall financial savings. As for radiant and hot air systems, their overall financial status falls between that of the hot water system and the heat pump. The radiant system proved to be more energy efficient that the hot air system, but the latter produced a higher marketable fruit yield over the 2-year study.


1998 ◽  
Vol 50 (2) ◽  
pp. 157-166 ◽  
Author(s):  
Helge W. Arz ◽  
Jürgen Pätzold ◽  
Gerold Wefer

The stable isotope composition of planktonic foraminifera correlates with evidence for pulses of terrigenous sediment in a sediment core from the upper continental slope off northeastern Brazil. Stable oxygen isotope records of the planktonic foraminiferal species Globigerinoides sacculiferand Globigerinoides ruber(pink) reveal sub-Milankovitch changes in sea-surface hydrography during the last 85,000 yr. Warming of the surface water coincided with terrigenous sedimentation pulses that are inferred from high XRF intensities of Ti and Fe, and which suggest humid conditions in northeast Brazil. These tropical signals correlate with climatic oscillations recorded in Greenland ice cores (Dansgaard-Oeschger cycles) and in sediment cores from the North Atlantic (Heinrich events). Trade winds may have caused changes in the North Brazil Current that altered heat and salt flux into the North Atlantic, thus affecting the growth and decay of the large glacial ice sheets.


2012 ◽  
Vol 193-194 ◽  
pp. 30-33
Author(s):  
Xue Ying Wang ◽  
Dong Xu ◽  
Ya Jun Wu

This article analyzes the problem in application the solar system was used in residential building, puts forward the requirements to use energy and choose the setting of the solar energy collector from two aspects of building and drainage design respectively. In addition, the article explicates andthe solar energy collector and building integrated design and the development of solar energy collector. At last, the article puts forward some Suggestions on the improvement and development of residential solar hot water system and the design of the hot water supply bath solution of practice to make solar energy and low power assisted by night combining.


2013 ◽  
Vol 316-317 ◽  
pp. 176-180 ◽  
Author(s):  
Xue Jing Zheng ◽  
Meng Jun Yang ◽  
Wan Dong Zheng ◽  
Yun Kun Bu

Sino-Singapore Tianjin Eco-city is a strategic cooperation project between China and Singapore to improve the living environment and build an eco-culture. Animation-park covers an area of 1 km2, with a total construction area of 7.7x105m2. Wide sources of the renewable energy, such as solar hot water system, ground source heat pump system, solar PV power generation system, and deep geothermal energy system, is strongly recommended to use in eco-city in order to save energy and protect the environment. The usage of renewable energy is seen as a complement to the conventional energy. The energy consumption of the animation park is 42926tce of coal per year, and the renewable energy that used is 4573.6tce of coal per year. The usage of renewable energy leads to the reduction in the emission of CO2 of 18895.9t per year.


2013 ◽  
Vol 315 ◽  
pp. 783-787
Author(s):  
M.Yaakob Yuhazri ◽  
A.M. Kamarul ◽  
A.H. Rahimah ◽  
Sihombing Haeryip ◽  
S.H. Yahaya

This research is related to thermal efficient water heating system, specifically to improve the water heating system that exists nowadays. The goal of this research is to improve the current water heating system by using solar heat as the energy source to heat the water. The focus is to improve the thermal efficiency by adding different thermal boxes as the absorber bed. By implementing the black body and radiation concept, the air trapped in the box is heated. The trapped air then increases the collisions between the molecules and directly increases the temperature inside the box, higher than the outside environment. Based on a daytime experimental result revealed steel thermal box is better to be used for tropical weather like Malaysia.


Sign in / Sign up

Export Citation Format

Share Document