A Moored Arctic Floater in First-Year Sea Ice Ridges

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Oddgeir Dalane ◽  
Vegard Aksnes ◽  
Sveinung Løset
Keyword(s):  
Sea Ice ◽  
Cross Sectional Area ◽  
The Arctic ◽  
First Year ◽  
Sectional Area ◽  
Cross Sectional ◽  
Ridge Structure ◽  
Structure Interaction ◽  
Ship Model ◽  
Mooring Forces

First-year sea ice ridges are a major concern for structures operating in the Arctic offshore and will in many cases give the design mooring load. In this paper, the response of a moored conical floater, somewhat similar to the well-known Kulluk, is studied in first-year ridges. The study is based on model tests performed at Hamburg Ship Model Basin (HSVA) in several ridges with different properties. Mooring forces and floater response, resulting from interaction with different ridges, were compared with respect to ridge properties, ridge behavior, and simulated ice management. Clearance of accumulated rubble upstream the structure was the dominating physical process in the ridge–structure interaction. Accumulation of rubble caused large mooring forces. The amount of accumulated rubble depended on the ridge cross-sectional area, thus the mooring forces increased with ridge cross-sectional area. Large mooring forces were also experienced after the ridge was passed by the structure due to difficulties with clearing of accumulated rubble.

A Moored Arctic Floater in First-Year Sea Ice Ridges

2009 ◽  
Author(s):  
Oddgeir Dalane ◽  
Vegard Aksnes ◽  
Sveinung Lo̸set ◽  
Jan Vidar Aarsnes
Keyword(s):  
Sea Ice ◽  
Initial Position ◽  
Cross Sectional Area ◽  
The Arctic ◽  
First Year ◽  
Sectional Area ◽  
Cross Sectional ◽  
Ridge Structure ◽  
Structure Interaction ◽  
Mooring Forces

First-year sea ice ridges are a major concern for structures operating in the Arctic and will in many cases give the design mooring load. In this paper, a moored conical floater, somewhat similar to the well-known Kulluk, is studied in first-year ridges. The study is based on model tests performed at HSVA in several ridges with different properties. Mooring forces and floater response resulting from interaction with different ridges were compared with respect to ridge properties, ridge behaviour and simulated ice management. Clearance of accumulated rubble upstream the structure was the dominating physical process in the ridge-structure interaction. Accumulation of rubble caused large mooring forces. The amount of accumulated rubble depended on the ridge cross-sectional area, thus the mooring forces increased with ridge cross-sectional area. Large mooring forces were also experienced after the initial position of the ridge was passed due to difficulties with clearing of accumulated rubble.

scholarly journals Mechanical Properties of First Year Sea Ice in Saroma Lagoon

1985 ◽  
Vol 6 ◽  
pp. 278-280
Author(s):  
Hisao Matsushita ◽  
Nobuyoshi Yashima
Keyword(s):  
Compressive Strength ◽  
Sea Ice ◽  
Test Specimen ◽  
Bending Strength ◽  
Growth Direction ◽  
Cross Sectional Area ◽  
First Year ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Cross

This paper deals with compressive strength vs temperature characteristics (-40 ºC to -2ºC), size effect (cross-sectional area of test specimen) and probability distribution of compressive strength and fracture toughness KIC (corresponding to notch effect in bending strength), of first year sea ice sampled from Saroma Lagoon. The main experimental results are as follows. (1) Temperature dependent compressive fracture modes: at temperatures of -20 ºC to 0ºC, crush fracture is dominant, and at temperatures of -40 ºC to -20 C, brittle fracture is dominant. (2) The larger the cross-sectional area of a test specimen, the lower the compressive strength becomes. It is inferred that the number of weak spots increases with increase in the cross-sectional area of the test piece, which thus becomes more susceptible to fracture. (3) The scatter of compressive strength can be approximated by a normal distribution curve. (4) The KIC values of sea ice are below 10 kg/cm2cm, though they change slightly depending on the dimensions of test pieces, the relative angle between crystal growth direction and load direction, environmental condition (air or water), and testing method.

scholarly journals Mechanical Properties of First Year Sea Ice in Saroma Lagoon

1985 ◽  
Vol 6 ◽  
pp. 278-280
Author(s):  
Hisao Matsushita ◽  
Nobuyoshi Yashima
Keyword(s):  
Compressive Strength ◽  
Sea Ice ◽  
Test Specimen ◽  
Bending Strength ◽  
Growth Direction ◽  
Cross Sectional Area ◽  
First Year ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Cross

This paper deals with compressive strength vs temperature characteristics (-40 ºC to -2ºC), size effect (cross-sectional area of test specimen) and probability distribution of compressive strength and fracture toughness KIC (corresponding to notch effect in bending strength), of first year sea ice sampled from Saroma Lagoon. The main experimental results are as follows. (1) Temperature dependent compressive fracture modes: at temperatures of -20 ºC to 0ºC, crush fracture is dominant, and at temperatures of -40 ºC to -20 C, brittle fracture is dominant. (2) The larger the cross-sectional area of a test specimen, the lower the compressive strength becomes. It is inferred that the number of weak spots increases with increase in the cross-sectional area of the test piece, which thus becomes more susceptible to fracture. (3) The scatter of compressive strength can be approximated by a normal distribution curve. (4) The KIC values of sea ice are below 10 kg/cm2 cm, though they change slightly depending on the dimensions of test pieces, the relative angle between crystal growth direction and load direction, environmental condition (air or water), and testing method.

Fluid–Structure Interaction in the Flexible Porous Stratification Manifold

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Shuping Wang ◽  
Jane H. Davidson
Keyword(s):  
Fluid Structure Interaction ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Neutral Buoyancy ◽  
Cross Sectional ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Water Heaters ◽  
Solar Water Heaters ◽  
Vertical Level

A model of the flexible porous manifold that captures the interaction between the flow field and the deformation of the manifold is developed and applied to understand how the fabric manifold works for conditions expected in solar water heaters. Contrary to the widely held hypothesis that the change of cross-sectional area induced by the fluid–structure interaction is beneficial, the numerical results demonstrate the change of cross-sectional area has no significant impact on the effectiveness of the manifold. In comparison to a rigid porous manifold, the performance of the flexible manifold is slightly worse because the collapse of the manifold encourages entrainment. The dimensionless permeability plays a crucial role in determining the performance and can be selected to limit entrainment and release fluid near the vertical level of neutral buoyancy.

scholarly journals 616 PB 296 GROWTH RESPONSES OF VERTICAL APPLE SHOOTS BENT WITH BRANCH BENDER' OR A HAND-TOOL

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 520d-520
Author(s):  
Alvan Gaus ◽  
Matthew Rogoyski
Keyword(s):  
Cluster Formation ◽  
Cross Sectional Area ◽  
First Year ◽  
Sectional Area ◽  
Growth Responses ◽  
Cross Sectional ◽  
Number Of Clusters ◽  
Single Tree ◽  
Hand Tool ◽  
Number Of Shoots

The main objective of this research was to compare the growth responses of l-year-old, vertical, apple shoots to bending with a simple hand-tool (HT) or bending with the commercially available Branch Bender® (BB). Single, vigorous, vertical shoots of `Red Chief Delicious (RCD), `Valnur' Jonathan (VJ), and Granny Smith were either bent with the BB or were bent by spirally wrapping the shoot around a 2.5 cm diameter plastic-rod, HT 2 times. Each variety had nine single-tree blocks with a control, BB, and HT as treatments. Measurements were taken on the number of clusters formed, length of subsequent terminal growth, number of shoots and spurs formed, and shoot cross-sectional area. No differences were found in RCD between the BB and the HT on all parameters; however, terminal growth was less with the BB than the control. With VJ, first year shoot cross-sectional area for the BB was less than for the HT. Cluster formation on both 1 and 2-year-old wood was greater with the BB than the control but not with the HT. No differences were found with Granny Smith.

scholarly journals 583 Field performance of Grafted Chestnut Cultivars and their Seedlings

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 547B-547
Author(s):  
Rachel Byard ◽  
Ian A. Merwin
Keyword(s):  
Mortality Rate ◽  
Interspecific Hybrid ◽  
Field Performance ◽  
Dry Weight ◽  
Cross Sectional Area ◽  
First Year ◽  
Sectional Area ◽  
Cross Sectional ◽  
Yield Efficiency ◽  
The Third

We planted grafted and seedling chestnuts of six cultivars in Lansing, N.Y., in April 1995 to evaluate performance of the different cultivars in our region and to compare grafted and seedling trees. We used the following cultivars: the Chinese chestnut cultivar Mossbarger (Castanea mollissima) and five interspecific hybrid cultivars [Douglas 1A (C. mollissima × C. dentata), Eaton [C. mollissima × (C. crenata × C. dentata)[, Skioka (C. mollissima × C. sativa), Layeroka (open-pollinated daughter of `Skioka'), and Grimo 142Q (an open pollinated daughter of `Layeroka')]. Growth was not significantly different between cultivars. There were no notable correlations between trunk cross-sectional area at planting and any measurement after the first year. Significant differences between cultivars were found for mortality, yield, and yield efficiency. `Eaton' had the lowest mortality rate (2%) of all cultivars. `Grimo 142Q' and `Layeroka' had the highest dry weight yields and the greatest yield efficiencies, although `Grimo 142Q' had significantly larger nuts than `Layeroka'. In 1998, the largest nuts (5.2 g) were harvested from `Mossbarger' and `Eaton trees'. `Skioka' had the highest mortality (48%), lowest yield, lowest yield efficiency, and smallest nut size. In the first 2 years, most grafted trees showed significantly higher yields and greater yield efficiency than seedling trees. By the third year, differences in yield between grafted and seedling trees were no longer significant for most cultivars. Over the 3 years most grafted trees revealed higher mortality and slower growth than seedlings of the same cultivar. Seedlings did not show more variability in measurements than grafted trees of the same cultivar.

Pelvic Canal Narrowing Caused by Triple Pelvic Osteotomy in the Dog

1994 ◽  
Vol 07 (03) ◽  
pp. 110-113 ◽  
Author(s):  
D. L. Holmberg ◽  
M. B. Hurtig ◽  
H. R. Sukhiani
Keyword(s):  
Postoperative Complications ◽  
Pelvic Osteotomy ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Canal Width ◽  
Operative Complications ◽  
Post Operative Complications

SummaryDuring a triple pelvic osteotomy, rotation of the free acetabular segment causes the pubic remnant on the acetabulum to rotate into the pelvic canal. The resulting narrowing may cause complications by impingement on the organs within the pelvic canal. Triple pelvic osteotomies were performed on ten cadaver pelves with pubic remnants equal to 0, 25, and 50% of the hemi-pubic length and angles of acetabular rotation of 20, 30, and 40 degrees. All combinations of pubic remnant lengths and angles of acetabular rotation caused a significant reduction in pelvic canal-width and cross-sectional area, when compared to the inact pelvis. Zero, 25, and 50% pubic remnants result in 15, 35, and 50% reductions in pelvic canal width respectively. Overrotation of the acetabulum should be avoided and the pubic remnant on the acetabular segment should be minimized to reduce postoperative complications due to pelvic canal narrowing.When performing triple pelvic osteotomies, the length of the pubic remnant on the acetabular segment and the angle of acetabular rotation both significantly narrow the pelvic canal. To reduce post-operative complications, due to narrowing of the pelvic canal, overrotation of the acetabulum should be avoided and the length of the pubic remnant should be minimized.

DETERMINATION OF THE FUNCTION OF THE ROD’S CROSS-SECTIONAL AREA USING VIBRATION EIGENFREQUENCIES

2020 ◽  
Vol 0 (4) ◽  
pp. 19-24
Author(s):  
I.M. UTYASHEV ◽  
◽  
A.A. AITBAEVA ◽  
A.A. YULMUKHAMETOV ◽  
◽  
...  
Keyword(s):  
Cross Sectional Area ◽  
Variable Cross ◽  
Sectional Area ◽  
Longitudinal Vibrations ◽  
Cross Sectional ◽  
Method Error ◽  
Various Boundary Conditions ◽  
Elastic Fixation ◽  
Crosssectional Area

The paper presents solutions to the direct and inverse problems on longitudinal vibrations of a rod with a variable cross-sectional area. The law of variation of the cross-sectional area is modeled as an exponential function of a polynomial of degree n . The method for reconstructing this function is based on representing the fundamental system of solutions of the direct problem in the form of a Maclaurin series in the variables x and λ. Examples of solutions for various section functions and various boundary conditions are given. It is shown that to recover n unknown coefficients of a polynomial, n eigenvalues are required, and the solution is dual. An unambiguous solution was obtained only for the case of elastic fixation at one of the rod’s ends. The numerical estimation of the method error was made using input data noise. It is shown that the error in finding the variable crosssectional area is less than 1% with the error in the eigenvalues of longitudinal vibrations not exceeding 0.0001.

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