scholarly journals Ship operation in brash ice: results of investigations

2021 ◽  
Vol 67 (4) ◽  
pp. 406-424
Author(s):  
K. E. Sazonov
Keyword(s):  
Physical Modeling ◽  
Experimental Studies ◽  
Theoretical Models ◽  
The Arctic ◽  
Experimental Investigations ◽  
Inland Waterways ◽  
Arctic Regions ◽  
Ice Conditions ◽  
Ice Resistance

The paper gives a review of the studies concerned with operation of vessels in brash ice. Recently, the ice conditions have received an ever increasing attention of the researchers related to the fact that shipping in the Arctic regions and freezing seas, as well as in inland waterways has been scaled up. One of the important fields of brash ice studies is specifics of sailing under these conditions and primarily determination of the ship ice resistance. The paper shows that theoretical methods combined with physical modeling in ice basins are used for determination of the ship ice resistance under brash ice conditions. The paper traces the evolution of theoretical models utilized for calculations. It is mentioned that the models are mainly based on loose material mechanics. A rapidly developing computer modeling of ship motion in brash ice based on discrete element method is considered. Physical modeling techniques used for modeling brash ice in ice basin are described, and challenges of experimental investigations are discussed. It is pointed out that experimental studies in ice basin can provide valuable data not only about ship ice resistance but also about the mechanisms giving rise to ice channels filled with brash ice. The paper describes the methods for studying operation of ship propellers in brash ice conditions. It is concluded that further research into brash ice is needed.

scholarly journals Experimental Evaluation of Airlift Performance for Vertical Pumping of Water in Underground Mines

2021 ◽  
Author(s):  
Parviz Enany ◽  
Oleksandr Shevchenko ◽  
Carsten Drebenstedt
Keyword(s):  
Water Flow ◽  
High Efficiency ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Injection System ◽  
Experimental Investigations ◽  
Flow Mode ◽  
New Device ◽  
Riser Pipe ◽  
Airlift Pump

AbstractThis paper presents experimental studies on the optimization of air–water flow in an airlift pump. Airlift pumps use compressed gas to verticall transport liquids and slurries. Due to the lack of theoretical equations for designing and predicting flow regimes, experimental investigations must be carried out to find the best condition to operate an airlift pump at high efficiency. We used a new air injection system and different submergence ratios to evaluate the output of a simple pump for vertical displacement of water in an underground mine. The tests were carried out in a new device with 5.64 m height and 10.2 cm circular riser pipe. Three air-jacket pipes, at different gas flows in the range of 0.002–0.09 m3/s were investigated with eight submergence ratios. It was found that with the same air flow rate, the most efficient flow of water was achieved when an air jacket with 3 mm diameter holes was used with a submergence ratio between 0.6 and 0.75. In addition, a comparison of practical results with two theoretical models proposed by other investigators showed that neither was able to accurately predict airlift performance in air–water flow mode.

Specific Features of Blasting Operations in Mining Minerals in Northern and Arctic Regions of Russia

2021 ◽  
pp. 102-106
Author(s):  
V.A. Tikhonov ◽  
G.A. Dudnik ◽  
S.Yu. Panfilov ◽  
V.V. Zhulikov
Keyword(s):  
Size Composition ◽  
The Arctic ◽  
Physical Parameters ◽  
Arctic Zone ◽  
Arctic Regions ◽  
Priority Task ◽  
Geological Conditions ◽  
The Russian Federation ◽  
Remote Operations

A priority task for facilitating the development of the Arctic zone of the Russian Federation is to design new blasting technologies to be efficiently used in extremely difficult climatic, mining and geological conditions at remote operations. This is further motivated by the fact that up to 40% of Russia's gold reserves, 60–90% of its natural gas resources and 100% of its primary diamond deposits are located in the Arctic zone. The article analyses the problems of blasting operations while developing deposits in the Arctic zone. The main formulations of ordinary explosives are reviewed that allow to solve a number of challenges associated with blasting operations in remote and hard-to-reach Arctic regions. Based on the performed analysis of existing methods, further areas of research are identified that can improve the quality and safety of blasting operations: 1) determination of optimum weight and dimensions of boosters based on ordinary explosives depending on the initiating borehole size; 2) determination of the relation between the particle size / composition of the booster and the detonation velocity; 3) determination of physical parameters of transition from deflagration to detonation and gaining sensitivity to the initiating pulse from the detonator cap by the ordinary explosive compositions.

A Review of Research to Aid the Development of Commercial Arctic Marine Transportation: 1982 Trafficability Tests on the USCGC Polar Star

1985 ◽  
Vol 22 (01) ◽  
pp. 28-35
Author(s):  
Seibold Frederick
Keyword(s):  
Ice Cores ◽  
Coast Guard ◽  
The Arctic ◽  
Marine Transportation ◽  
Newport News ◽  
Research Activities ◽  
Ice Conditions ◽  
Level Ice ◽  
Ice Resistance ◽  
Resistance Tests

A multi-year "trafficability" research program was begun in 1978 to demonstrate that year-round commercial marine transportation in Arctic waters is feasible and to collect data necessary to begin developing the criteria to design and operate marine vehicles for that environment. Using U.S. Coast Guard Polar Class icebreakers, annual winter deployments had been made in 1979, 1980, and 1981 into the Bering and Chukchi Seas to collect environmental and ship performance data. Early in 1982, the fourth phase of these research activities was conducted on the USCGC Polar Star in western Alaskan waters as far north as the Arctic Circle. Participants in the research were the Maritime Administration, the U.S. Coast Guard, the State of Alaska, the Canadian Ministry of Transport, twelve participating companies of the Alaskan Oil and Gas Association, and the Newport News Shipbuilding Company. This paper reviews the results of this voyage and the data collected. The Polar Star was instrumented to continuously monitor and record propulsion and ship motion parameters and speed. Video recording equipment was used to document ice conditions. Extensive on-ice equipment was used to profile ice features and to measure other ice parameters. Numerous pressure ridges were profiled and ice cores taken to improve the understanding of Bering and Chukchi Sea winter ice conditions and ice strength. Level ice resistance tests were conducted. However, heavy level ice conditions were not encountered and it is planned to complete the level ice resistance tests in 1984. Other research tasks included an ice edge analysis, hull friction experiments, and an ice drift study.

Risk-based Winterization for Vessels Operations in Arctic Environments

2013 ◽  
Vol 29 (04) ◽  
pp. 199-210 ◽  
Author(s):  
Ming Yang ◽  
Faisal I. Khan ◽  
Leonard Lye ◽  
Heri Sulistiyono ◽  
John Dolny ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Temperature Data ◽  
Operating Conditions ◽  
Hydrocarbon Exploration ◽  
The Arctic ◽  
Gas Industry ◽  
Arctic Regions ◽  
Exploration And Production

Because the oil and gas industry has an increasing interest in the hydrocarbon exploration and development in the Arctic regions, it becomes important to design exploration and production facilities that suit the cold and harsh operating conditions. In addition to well-established minimum class requirements for hull strengthening, winterization should be considered as a priority measure early in the design spiral for vessels operating in the Arctic environments. The development of winterization strategies is a challenging task, which requires a robust decision support approach. This article proposes a risk-based approach for the selection of winterization technologies and determination of winterization levels or requirements on a case-by-case basis. Temperature data are collected from climatology stations located in the Arctic regions. Loading scenarios are defined by statistical analysis of the temperature data to obtain probabilistic distributions for the loadings. Risk values are calculated under different loading scenarios. Based on the risk values, appropriate winterization strategies can be determined. A case study is used to demonstrate how the proposed approach can be applied to the identification of heating requirements for gangways.

scholarly journals Analysis of responses in the dynamics of sea ice area in separate regions of the Arctic to change of insolation

2020 ◽  
pp. 17-33
Author(s):  
Valerii Mikhailovich Fedorov ◽  
Pavel Borisovich Grebennikov ◽  
Denis Maksimovich Frolov
Keyword(s):  
Sea Ice ◽  
Interannual Variability ◽  
Northern Hemisphere ◽  
Barents Sea ◽  
The Arctic ◽  
Arctic Regions ◽  
Monthly Changes ◽  
The Subject

The subject of this research is the correlation analysis of changes in the area of sea ice in separate regions of the Arctic, and levels of internal regional correlations between multiyear monthly changes in the area of sea ice of different seas and the entire Arctic Ocean. The author also examines peculiarities in the annual amplitude course of interannual variability of monthly indices of the area of sea ice for separate districts of the Arctic, interregional links in the annual course of this amplitude of interannual variability, and determination of correlation between the annual indices of the area of sea ice with annual insolation contrast for various Arctic regions. The research method is the correlation data analysis on the area of distribution of sea ice in different districts of the Arctic and insolation contrast. The author builds an algorithm of the value forecast in the changes of sea ice area. Based on the analysis of internal correlations between multiyear and annual changes in the sea ice area in the Arctic regions, and connection with the insolation and insolation contrast, an algorithm is proposed for the value forecast of changes in the sea ice area in separate districts of the Arctic and Northern Hemisphere overall. For long-term forecast of annual values of the changes in sea ice area, the promising districts are Baffin Bay, Kara Sea, Barents Sea, Greenland Sea and Northern Hemisphere as a whole.

scholarly journals Breakdown in air gaps with solid insulating barrier under impulse voltage stress

2005 ◽  
Vol 18 (1) ◽  
pp. 87-104 ◽  
Author(s):  
Frangiskos Topalis ◽  
Michael Danikas
Keyword(s):  
High Voltage ◽  
Theoretical Models ◽  
Experimental Investigations ◽  
Barrier Effect ◽  
High Voltage Electrode ◽  
Insulating Materials ◽  
Air Gaps ◽  
Voltage Stress ◽  
Theoretical Analyses

The influence of solid insulating barriers to the impulse strength of air gaps has been investigated by few researchers. It is well known that thin insulating materials increase considerably the breakdown voltage, sometimes two to three times. Some researchers performed thorough investigations for the determination of the parameters of the barrier effect that influence the impulse level for the breakdown. The distance of the barrier from the high voltage electrode is the most important parameter. The field distribution is also important as well as the shape of the insulating sheet. The experimental investigations led to some theoretical models for the breakdown process. This paper analyzes and discusses those models and spots the points where they agree as well as the differences between them. Finally, it attempts to compose a model that sheds light on the barrier effect and complies with all the experimental and theoretical analyses.

scholarly journals Profiling Sea Ice with a Multiple Altimeter Beam Experimental Lidar (MABEL)

2014 ◽  
Vol 31 (5) ◽  
pp. 1151-1168 ◽  
Author(s):  
R. Kwok ◽  
T. Markus ◽  
J. Morison ◽  
S. P. Palm ◽  
T. A. Neumann ◽  
...  
Keyword(s):  
Sea Ice ◽  
Open Water ◽  
Laser Pulses ◽  
The Arctic ◽  
Ice Cloud ◽  
Ice Conditions ◽  
Arctic Coast ◽  
Background Photon ◽  
532 Nm

AbstractThe sole instrument on the upcoming Ice, Cloud, and Land Elevation Satellite (ICESat-2) altimetry mission is a micropulse lidar that measures the time of flight of individual photons from laser pulses transmitted at 532 nm. Prior to launch, the Multiple Altimeter Beam Experimental Lidar (MABEL) serves as an airborne implementation for testing and development. This paper provides a first examination of MABEL data acquired on two flights over sea ice in April 2012: one north of the Arctic coast of Greenland and the other in the east Greenland Sea. The phenomenology of photon distributions in the sea ice returns is investigated. An approach to locate the surface and estimate its elevation in the distributions is described, and its achievable precision is assessed. Retrieved surface elevations over relatively flat leads in the ice cover suggest that precisions of several centimeters are attainable. Restricting the width of the elevation window used in the surface analysis can mitigate potential biases in the elevation estimates due to subsurface returns at 532 nm. Comparisons of nearly coincident elevation profiles from MABEL with those acquired by an analog lidar show good agreement. Discrimination of ice and open water, a crucial step in the determination of sea ice freeboard and the estimation of ice thickness, is facilitated by contrasts in the observed signal–background photon statistics. Future flight paths will sample a broader range of seasonal ice conditions for further evaluation of the year-round profiling capabilities and limitations of the MABEL instrument.

scholarly journals Stick–slip vibrations in oil well drillstring: A review

2019 ◽  
Vol 39 (4) ◽  
pp. 885-907 ◽  
Author(s):  
Liping Tang ◽  
Baolin Guo ◽  
Xiaohua Zhu ◽  
Changshuai Shi ◽  
Yunlai Zhou
Keyword(s):  
Experimental Studies ◽  
Field Tests ◽  
Theoretical Models ◽  
Experimental Investigations ◽  
Oil Well ◽  
Stick Slip ◽  
Key Concepts

A survey of the literature related to theoretical and experimental studies on stick–slip vibration in oilwell drillstring is carried out in this study. It aims to explain key concepts and present the existing methods for studying this phenomenon. After briefly describing the stick–slip vibration related problems, theoretical models for such phenomenon are discussed including both coupled and uncoupled models. Discussion for experimental investigations including both laboratory and field tests are hereinafter addressed. This study aims to summarize the literature related to the stick–slip vibration, and help researchers in understanding and suppressing such phenomenon.

Ice Condition Database for the Arctic Sea

2014 ◽  
Author(s):  
Tõnis Tõns ◽  
Sandro Erceg ◽  
Sören Ehlers ◽  
Bernt Johan Leira
Keyword(s):  
Arctic Sea Ice ◽  
The Arctic ◽  
Sea Transport ◽  
The Past ◽  
Arctic Sea ◽  
Ice Conditions ◽  
Data Source ◽  
Increasing Trends

Increasing trends in the arctic sea transport lead to the necessity to determine route specific ice conditions to ensure safe vessel transits. In order to achieve this, the comprehensive understanding of ice conditions from the past should be used to predict future trends for arctic sea ice conditions. This paper presents the development of such ice conditions database with the implementation of a satellite data source, which will become a basis for the determination of route specific ice conditions. A case study is performed in order to show how the database could be used to collect the route specific ice data for statistical analyses.

scholarly journals Professional Self-Determination of Schoolchildren in Years 8–10 of Arctic and Russian Far East Regions: Sociological Analysis

2019 ◽  
Vol 7 (3) ◽  
pp. 72-91
Author(s):  
Anna V. Simakova
Keyword(s):  
Career Guidance ◽  
Russian Far East ◽  
Far East ◽  
Self Determination ◽  
The Arctic ◽  
Arctic Regions ◽  
The Far East ◽  
Qualified Personnel ◽  
Professional Self

The article deals with the features of professional self-determination of schoolchildren in years 8–10 of Arctic and Russian Far East regions. The study revealed factors that influence the choice of future professions by schoolchildren; generalized schoolchildren’s ideas about the category of “profession” and its content; analyzed ideas of schoolchildren about their professional future; considered the interests of schoolchildren in building a successful career in the Arctic and Russian Far East regions. The results obtained showed that schoolchildren are more oriented towards higher education, and their chosen professions are in demand in the Arctic and Russian Far East regions where there is a deficit of qualified personnel. The students are optimistic about their professional future, and they also positively assess the opportunities of starting a career with Arctic and Far East companies. Every tenth pupil from Arctic regions and every fifth pupil from the Far East regions noted that they had planned professional implementation in these regions earlier, almost every third pupil was interested in it, but they are not sure that it suits them. The results of the research may be useful in planning themed career guidance activities aimed at involving young people in strategic regions of the country, and useful for career guidance specialists, educators, relevant authorities and researchers.

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