scholarly journals Technical innovations and optimizations for intermediate ice-core drilling operations

2014 ◽  
Vol 55 (68) ◽  
pp. 243-252 ◽  
Author(s):  
Jack Triest ◽  
Robert Mulvaney ◽  
Olivier Alemany
Keyword(s):  
Ice Core ◽  
Working Environment ◽  
Column Height ◽  
Drill Fluid ◽  
Drilling Operations ◽  
Remote Sites ◽  
James Ross Island ◽  
Technical Innovations ◽  
Set Up ◽  
Core Storage

AbstractThe British Antarctic Survey, in collaboration with Laboratoire de Glaciologie et Géophysique de l’Environnement, has in recent years successfully drilled to bedrock on three remote sites around the Antarctic Peninsula. Based on the experience from the multi-season project at Berkner Island (948m depth, 2002–05) we optimized the drill set-up to better suit two subsequent single-season projects at James Ross Island (363m depth, 2008) and Fletcher Promontory (654m depth, 2012). The adaptations, as well as the reasons for them, are discussed in detail and include a drill tent set-up without a trench; drilling without a borehole casing with a relatively low fluid column height; and using a shorter drill. These optimizations were aimed at reducing cargo loads and installation time while maintaining good core quality, productivity and a safe working environment. In addition, we introduce a number of innovations, ranging from a new lightweight cable tensioning device and drill-head design to core storage and protection trays. To minimize the environmental impact, all the drill fluid was successfully recovered at both sites and we describe and evaluate this operation.

scholarly journals Production drilling at WAIS Divide

2014 ◽  
Vol 55 (68) ◽  
pp. 147-155 ◽  
Author(s):  
Kristina R. Slawny ◽  
Jay A. Johnson ◽  
Nicolai B. Mortensen ◽  
Christopher J. Gibson ◽  
Joshua J. Goetz ◽  
...  
Keyword(s):  
Ice Core ◽  
Ice Sheet ◽  
Austral Summer ◽  
Snow Surface ◽  
Scientific Interest ◽  
High Quality ◽  
Core Drilling ◽  
Core Samples ◽  
Drill Fluid ◽  
Drilling Operations

AbstractThe deep ice-sheet coring (DISC) drill was used for production ice-core drilling at WAIS Divide in Antarctica for six field seasons between 2007 and 2013. Continuous ice-core samples were obtained between the snow surface and 3405 m depth. During the 2012/13 austral summer, the DISC drill’s newly designed replicate ice-coring system was utilized to collect nearly 285m of additional high-quality core samples at depths of high scientific interest. Annual progress graphs are described, as well as milestones achieved over the course of the project. Drilling operations, challenges encountered, drill fluid usage, drilling results, and the drill crew’s experiences with the DISC drill and replicate coring system during production drilling are described and discussed in detail. Core-processing operations are described briefly, as well as the logistical undertaking of the DISC drill’s deployment to Antarctica.

scholarly journals Deep ice-core drilling performance and experience at NEEM, Greenland

2014 ◽  
Vol 55 (68) ◽  
pp. 53-64 ◽  
Author(s):  
Trevor J. Popp ◽  
Steffen B. Hansen ◽  
Simon G. Sheldon ◽  
Christian Panton
Keyword(s):  
Drilling Fluid ◽  
Ice Core ◽  
Borehole Diameter ◽  
Extended Version ◽  
Core Drilling ◽  
Drilling Operation ◽  
Design And Implementation ◽  
Drilling Performance ◽  
Drill Fluid ◽  
Drilling Operations

AbstractThe NEEM deep ice-core drilling in northwest Greenland was completed in summer 2010 after three seasons, which included establishing all drilling infrastructure. Normal drilling operations in the main borehole were declared terminated at 2537.36 m below the surface, when further penetration was stopped by a stone embedded in the ice in the path of the drill head. The design and implementation of the drilling operation strongly resembled the NGRIP drilling program. The NEEM drill was an extended version of the Hans Tausen (HT) drill, with specific modifications to optimize its use with the highly viscous Estisol-240/Coasol drill fluid used at NEEM. Modification to the drill and its performance in the new drilling fluid was largely satisfactory and successful. Throughout the drilling, special consideration was given to the way chips were transported and collected in a new chip chamber, including the consequences of drilling a larger borehole diameter than with previous drill operations that used the HT family of drills. The problems normally associated with warm ice drilling near the base of an ice sheet were largely absent at NEEM.

scholarly journals Wear and Friction Characteristics of 65Mn Steel for Spike-Tooth Harrow

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 319
Author(s):  
Zhiguo Lu ◽  
Chuanyu Du ◽  
Qingcai Chen ◽  
Tianying Niu ◽  
Na Wang ◽  
...  
Keyword(s):  
Friction And Wear ◽  
Working Environment ◽  
Manganese Steel ◽  
Wear Loss ◽  
Variable Parameters ◽  
Wear Characteristics ◽  
Before And After ◽  
Set Up ◽  
Worn Surface ◽  
Friction And Wear Characteristics

The friction and wear characteristics of spike-tooth material (65Mn steel) of Spike-Tooth Harrow in a two-stage peanut harvester were studied in this paper. The friction and wear tests of pin and disc on 65 manganese steel were carried out on the tribometer, then the wear loss and the friction coefficient were studied. The wear loss of the pin was acquired by calculating the mass of the pin before and after the experiment using an electronic balance. According to the actual working environment of peanut spring-finger, four variable parameters are set up: load, speed, soil moisture and soil type. The friction and wear characteristics of pins were studied under different loads, speeds and different soil environments. After wearing, the worn surface of the material was observed by scanning microscope and the wear mechanism was studied. The experimental results show that the wear of the pin increases with the increase of load and decreases with the increase of rotational speed in the same rotation number. Especially in the case of the sandy soil with 20% in moisture, a maximum wear loss of the pin is achieved.

Een slechte start en dan?

2017 ◽  
Vol 33 (3) ◽  
Author(s):  
Henk-Jan Dirven ◽  
Wouter van der Torre ◽  
Seth van den Bossche
Keyword(s):  
Analysis Data ◽  
Working Environment ◽  
Work Situation ◽  
Financial Situation ◽  
Work Related ◽  
Self Employment ◽  
Level Of Satisfaction ◽  
Set Up ◽  
Employment Quality

A bad start and what then? The work situation of self-employed entrepreneurs with negative and positive start motives This article assesses the extent to which the quality of labor varies between solo self-employed who set up a business for negative reasons and those who started for positive reasons. A negative reason is, for example, not being able to find a suitable job as an employee; an example of a positive reason is wanting to be self-employed from the very beginning. Quality of labor is measured according to the person's financial situation, security of employment, quality of the working environment and work satisfaction. In the analysis, data are used from the Self-employment Survey conducted by Statistics Netherlands and TNO. Compared to self-employed persons with a positive motivation, those who were negatively motivated show lower performance in terms of their business's financial situation, income position, work-related mental fatigue (burn-out), self-perceived health status, concern about the business's future and the level of satisfaction. However, in absolute terms, the vast majority appear to be satisfied with their work situation, enthusiastic and not intending to quit self-employment.

Case Study of the St. Paul Companies Virtual Office for the Risk Control Division

2011 ◽  
pp. 60-71
Author(s):  
Nancy Johnson
Keyword(s):  
Working Conditions ◽  
Risk Control ◽  
Working Environment ◽  
Personal Lives ◽  
Virtual Office ◽  
Office Space ◽  
Construction Risk ◽  
Remote Sites ◽  
Control Division

The St. Paul Companies has successfully implemented a virtual office (VO) working environment for their US distributed construction risk control and commercial risk control employees over the past six years. The program goals of operating more cost effectively, increasing contact of the risk control specialists with their customers, and reducing office space costs for The St. Paul Companies have been met. There are many good practices that have been developed over the six years of offering the program, and more refinements and changes planned. As the communications and computer technologies advance, facilitation of working from remote sites improves. While it is easier for employees to work from remote sites, maintaining the boundaries between work and personal lives is more challenging. Improving the VO employees’ and corporate employees’ understanding of the other’s working conditions is necessary to improve relationships and the acceptance of change. The concept of VO work is well established within the organization, and the demand for it is growing.

scholarly journals 200-Hundred Year Climate Record From Antarctic Peninsula

1990 ◽  
Vol 14 ◽  
pp. 353-353
Author(s):  
D.A. Peel ◽  
R. Mulvaney
Keyword(s):  
Antarctic Peninsula ◽  
Ice Core ◽  
Weddell Sea ◽  
Average Temperature ◽  
Air Temperatures ◽  
Isotope Record ◽  
James Ross Island ◽  
Weather Stations ◽  
Isotopic Records ◽  
Reported Data

A stable isotope record extending back to 1795 is now available from Dolleman Island (70°35.2′S, 60°55.5′W), a small ice rise on the Weddell Sea coast of Antarctic Peninsula. An accurate chronology has been achieved by combined stratigraphic analysis of clear seasonal cycles in δ18O and excess SO4. Previous work (Peel and others, 1988) has shown that, since 1947, there is generally a satisfactory correlation between interannual variations in δ18O and air temperature (T) as recorded at weather stations in various parts of the region, suggesting that the derived δ18O/T ratio may be used to reconstruct air temperatures for the earlier period.Taken together with previously-reported data (Aristarain and others, 1986) for an ice core from James Ross Island it is now possible to propose a regional climatic signal for the Weddell Sea coastal sector of the region. The most striking feature is a broad maximum in δ18O for the mid-19th century, implying decadal average temperature at least as high as the present. This contrasts with available evidence from elsewhere in the southern hemisphere which suggest that this period was cooler than today. Tentative explanations for the anomaly are proposed based on evidence for a period (1974–80), where climatic shifts are clearly amplified in the isotopic records.

Versatile Work Holding Device for Hole Drilling in Small-Scale Production Workshops

2007 ◽  
Vol 18-19 ◽  
pp. 481-486
Author(s):  
John U. Okoli ◽  
Tamuno K. Jinyemiema
Keyword(s):  
Steel Plates ◽  
Hole Drilling ◽  
Small Scale ◽  
Work Piece ◽  
Scale Production ◽  
Production Operation ◽  
Irregular Shapes ◽  
Holding Device ◽  
Drilling Operations ◽  
Set Up

This devise addresses the inadequacies of providing a quick means of holding jobs of irregular shapes such as are encountered in small scale fabrication workshops. The conventional bench vise often does not provide the adequate grip for such shapes so that attachments in the form of V blocks are usually provided to enhance the grip before drilling operations are carried out. This versatile work holding device enables fabricators to perform drilling and other production operations on a work piece. This device produced from mild steel plates uses the toggle principle to provide rapid grip. Comparative tests on time span in the use of this device and the bench vice for job set up, production operation and then disassembly showed that time is gained with use of the device.

scholarly journals Methanesulphonic acid loss during ice-core storage: recommendations based on a new diffusion coefficient

2009 ◽  
Vol 55 (193) ◽  
pp. 784-788 ◽  
Author(s):  
Jason L. Roberts ◽  
Tas D. Van Ommen ◽  
Mark A.J. Curran ◽  
Tessa R. Vance
Keyword(s):  
Diffusion Coefficient ◽  
Ice Core ◽  
Ice Cores ◽  
Core Surface ◽  
Phonic Acid ◽  
Core Storage ◽  
Storage Times

AbstractThe loss of methanesul phonic acid (MSA) from stored ice cores can be significant over typical storage times, with diffusion to the ice-core surface controlling the loss. Methods for minimizing this loss are discussed and it is shown how measurements can be corrected by calculating the amount of MSA lost. A revised diffusion coefficient for MSA in solid ice, (4.1 × 10−13) ± (2.5 × 10−14) m2 s−1, is derived to improve such MSA loss corrections.

scholarly journals Drilling into debris-rich basal ice at the bottom of the NEEM (Greenland) borehole

2014 ◽  
Vol 55 (68) ◽  
pp. 199-206 ◽  
Author(s):  
Trevor J. Popp ◽  
Steffen B. Hansen ◽  
Simon G. Sheldon ◽  
Jakob Schwander ◽  
Jay A. Johnson
Keyword(s):  
Ice Core ◽  
Diamond Cutting ◽  
Additional Material ◽  
Rock Fragments ◽  
Rock Drill ◽  
Climate Reconstructions ◽  
Basal Ice ◽  
Drilling Operations ◽  
Field Season ◽  
Final Closure

AbstractAfter the NEEM (Greenland) deep ice-core drilling was declared terminated with respect to developing stratigraphic climate reconstructions, efforts were turned toward collecting basal ice-sheet debris and, if possible, drilling into the bedrock itself. In 2010, several meters of banded debris-rich ice were obtained under normal ice-drilling operations with the NEEM version of the Hans Tausen (HT) drill, but further penetration was obstructed by a rock in the path of the drill head at 2537.36 m. During short campaigns in 2011 and 2012, attempts were made to penetrate further using various reinforced ice cutters mounted on the HT drill head, tailored to cut through rock. These had some success in penetrating coarse material, but produced severely damaged cutters. Additionally a 51 mm diameter diamond cutting tipped rock drill was adapted to fit the NEEM drill. With this device, several additional meters of core containing subglacial sediments, rocks and rock fragments were collected. With these tools 1.39m of additional material were obtained during the 2011 field season, and 7.1 m during 2012. Subglacial water refreezing into the newly formed borehole hindered further penetration, and the bedrock interface was not reached before final closure of the NEEM Camp.

scholarly journals Post-depositional changes in snow isotope content: preliminary results of laboratory experiments

2009 ◽  
Vol 5 (5) ◽  
pp. 2239-2267 ◽  
Author(s):  
A. A. Ekaykin ◽  
T. Hondoh ◽  
V. Y. Lipenkov ◽  
A. Miyamoto
Keyword(s):  
Water Vapor ◽  
Isotope Exchange ◽  
Laboratory Experiments ◽  
Ice Core ◽  
Relative Mass ◽  
Atmospheric Water ◽  
Preliminary Results ◽  
Set Up ◽  
Isotope Content ◽  
Snow Thickness

Abstract. Isotopic content of the snow and firn thickness is assumed to be altered significantly due to the post-depositional (PD) mass- and isotope exchange with the atmospheric water vapor. If so, these effects should be accounted for in the ice core-based isotope-temperature paleo-reconstructions. In order to study the intensity of the PD processes we set up a series of laboratory experiments. In this paper we describe in detail the experimental technique and briefly overview preliminary results. It is shown that the PD modifications in the upper layer of snow thickness are noticeably strong even under such a low temperature as −35°C (the value typical for the Central Antarctic summer). It is demonstrated that the PD isotopic changes in snow can be approximated as a linear function of the relative mass loss due to snow sublimation. Possible applications for improving the isotope-temperature paleo-reconstructions are shortly discussed.

Sign in / Sign up

Export Citation Format

Share Document