scholarly journals Ice discharge error estimates using different cross-sectional area approaches: a case study for the Canadian High Arctic, 2016/17

2018 ◽  
Vol 64 (246) ◽  
pp. 595-608 ◽  
Author(s):  
PABLO SÁNCHEZ-GÁMEZ ◽  
FRANCISCO J. NAVARRO
Keyword(s):  
Cross Sections ◽  
High Arctic ◽  
Thickness Measurement ◽  
Cross Sectional Area ◽  
Medium Size ◽  
Ice Thickness ◽  
Sectional Area ◽  
Canadian High Arctic ◽  
Cross Sectional ◽  
Ice Cap

ABSTRACTWe analyse the various error sources in the estimation of ice discharge through flux gates, distinguishing the cases with ice-thickness data available for glacier cross-sections or only along the centreline. For the latter, we analyse the performance of three U-shaped cross-sectional approaches. We apply this methodology to glaciers of the Canadian High Arctic. The velocity field is the main error source for small and medium-size glaciers (discharge <100 Mt a−1) with low velocities (<100 m a−1), while for large glaciers (discharge >100 Mt a−1) with high velocities (>100 m a−1) the error in cross-sectional area dominates. Thinning/thickening between ice-thickness and velocity measurements should be considered, as it implies systematic errors up to 8% in our study. The U-shaped parabolic approach, which allows for an adjusted estimation when the ice-thickness measurement point is displaced from the glacier centreline, performs best, with small bias and admissible standard error. We observe an increase of ice discharge from the main glaciers (Trinity and Wykeham) of the Prince of Wales Icefield from 2015 to 2016, by 5 and 20%, respectively, followed by a decrease in 2017, by 10 and 15%, respectively. Belcher Glacier, of the Devon Ice Cap, maintains similar discharges during 2015–17.

Comparison of the Cross Sectional Area, the Loss in Volume and the Mechanical Properties of LAE442 and MgCa0.8 as Resorbable Magnesium Alloy Implants after 12 Months Implantation Duration

2010 ◽  
Vol 638-642 ◽  
pp. 675-680 ◽  
Author(s):  
Martina Thomann ◽  
Nina von der Höh ◽  
Dirk Bormann ◽  
Dina Rittershaus ◽  
C. Krause ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Degradation Process ◽  
Cross Sectional Area ◽  
Bending Test ◽  
Sectional Area ◽  
Cross Sectional ◽  
Initial Strength ◽  
Three Point Bending ◽  
The Cross

Current research focuses on magnesium based alloys in the course of searching a resorbable osteosynthetic material which provides sufficient mechanical properties besides a good biocompatibility. Previous studies reported on a favorable biocompatibility of the alloys LAE442 and MgCa0.8. The present study compared the degradation process of cylindrical LAE442 and MgCa0.8 implants after 12 months implantation duration. Therefore, 10 extruded implants (2.5 x 25 mm, cross sectional area 4.9 mm²) of both alloys were implanted into the medullary cavity of both tibiae of rabbits for 12 months. After euthanization, the right bone-implant-compound was scanned in a µ-computed tomograph (µCT80, ScancoMedical) and nine uniformly distributed cross-sections of each implant were used to determine the residual implants´ cross sectional area (Software AxioVisionRelease 4.5, Zeiss). Left implants were taken out of the bone carefully. After weighing, a three-point bending test was carried out. LAE442 implants degraded obviously slower and more homogeneously than MgCa0.8. The mean residual cross sectional area of LAE442 implants was 4.7 ± 0.07 mm². MgCa0.8 showed an area of only 2.18 ± 1.03 mm². In contrast, the loss in volume of LAE442 pins was more obvious. They lost 64 % of their initial weight. The volume of MgCa0.8 reduced clearly to 54.4 % which corresponds to the cross sectional area results. Three point bending tests revealed that LAE442 showed a loss in strength of 71.2 % while MgCa0.8 lost 85.6 % of its initial strength. All results indicated that LAE442 implants degraded slowly, probably due to the formation of a very obvious degradation layer. Degradation of MgCa0.8 implants was far advanced.

scholarly journals The accuracy of land form presentation in forest road Cross sections

2002 ◽  
pp. 91-99
Author(s):  
Bogdan Stefanovic ◽  
Velimir Aleksic
Keyword(s):  
Cross Sections ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Land Form ◽  
Volume Calculation ◽  
Forest Road ◽  
Earth Material ◽  
Legal Provisions ◽  
Natural Land

Accurate presentation of natural land forms directly affects the accuracy of earth volume calculation, the component of technical documentation of the forest road master project. Consistent to legal provisions, forest road master project is characterised by high accuracy of the planned scope of works compared to the realised scope of works, which should amount to ?3%. The volume of earth material is calculated based on the road cross-sectional area and the distance between the cross sections. The accuracy of the area of cross sections depends on the accuracy of land form presentation Accurate presentation of natural land forms depends on a great number of factors, the most significant of which are the methods of surveying and acquisition of data necessary for land form presentation, preciseness of equipment and instruments used in surveying and acquisition of data, and the method of land form presentation. The accuracy of earth material volume calculation depends on the method of computation, method of presentation of natural and artificial cross sections, and the phase of design. The presentation of natural land form in the width occupied by roadway cross section depends on the validity of the obtained station point elevation (Ht) and the elevations of detailed points (Hi). A relevant factor of the accuracy of cross sectional area, compared to its other elements, is the accuracy of the depth of cut or the height of fill (h) which should agree with the required accuracy, i.e. the adopted tolerance of the earthwork bill of quantities deviation up to 3%.

High Pressure Vertical Axis Wind Pump

2021 ◽  
Vol 143 (5) ◽  
Author(s):  
D. Keisar ◽  
B. Eilan ◽  
D. Greenblatt
Keyword(s):  
High Pressure ◽  
Vertical Axis ◽  
Cross Sectional Area ◽  
Liquid Volume ◽  
Medium Size ◽  
Small Scale ◽  
Sectional Area ◽  
Peak Efficiency ◽  
Cross Sectional ◽  
Positive Displacement

Abstract A novel positive displacement, high pressure, vertical axis wind pump (HP-VAWP) was evaluated for the application of stand-alone high-pressure reverse-osmosis desalination and drip irrigation systems. The direct interface between a vertical axis wind turbine (VAWT) and a positive displacement pump that delivers a constant liquid volume per revolution has never been studied before. Understanding the interaction between turbine and pump efficiencies, where delivery pressure is determined by back-pressure alone, is critical for efficient design. Wind tunnel experiments were conducted on a small-scale two-bladed turbine (0.4 m2 cross-sectional area) that operated on a dynamic stall principle. At these small laboratory scales, the turbine and pump peak efficiencies were relatively low (15% and 28%, respectively); nevertheless, the system produced nearly constant pressures in excess of 1.5 bar for a broad operational range. Moreover, the system exhibited a basic self-priming capability, and the turbine could easily be braked by overloading the pump. A conservative field-scale analysis of an HP-VAWP system indicated that a medium-size turbine (12.5 m2 cross-sectional area) could attain a peak efficiency of 12.9%. Realistic efficiencies greater than 20% are attainable, significantly exceeding the 4%–8% typical peak efficiency of the widely used American multibladed wind pumps. Indeed, our research indicates that an HP-VAWP system is viable and requires further development. The benefits of zero carbon emissions during operation, high relative efficiency, and easy manufacturing and maintenance render the HP-VAWP ideal for stand-alone or off-grid environments.

Genetic Effects on Skeletal Mechanosensitivity in Mice

2002 ◽  
Author(s):  
Charles H. Turner ◽  
Alexander G. Robling
Keyword(s):  
Mechanical Loading ◽  
Cross Sections ◽  
Inbred Mouse ◽  
Cross Sectional Area ◽  
Mouse Strains ◽  
Sectional Area ◽  
Mineral Density ◽  
Bone Apposition ◽  
Cross Sectional ◽  
Total Cross Sectional Area

The accumulation of bone mass during growth can be enhanced by environmental factors such as mechanical loading (exercise) or calcium intake, but 60–70% of the variance in adult bone mineral density (BMD) is explained by heredity. Consequently, understanding the signaling pathways targeted by the genes governing bone accumulation holds perhaps the greatest potential in reducing fracture incidence later in life. Rodent models are particularly useful for studying the genetics of skeletal traits. Of the available inbred mouse strains, three in particular have been studied extensively in skeletal genetics: C57BL/6, DBA/2, and C3H/He. The C57BL/6 strain is characterized by low BMD and large total cross-sectional area (CSA) in the midshaft femur; the C3H/He strain exhibits very high femoral BMD and a smaller femoral CSA than the C57BL/6 mice; and DBA/2 mice have moderately high femoral BMD and a very small midshaft femur CSA. Mechanical loading of the skeleton during growth can substantially enhance periosteal bone apposition, and ultimately produce a diaphyseal cross section with enlarged area. Therefore we hypothesized that the mouse strain with greater femoral cross-sectional area (C57BL/6) might have a genetic predisposition for greater mechanosensitivity than mice with smaller cross sections (C3H/He and DBA/2).

Absence of a growth hormone effect on rat soleus atrophy during a 4-day spaceflight

1993 ◽  
Vol 74 (2) ◽  
pp. 527-531 ◽  
Author(s):  
B. Jiang ◽  
R. R. Roy ◽  
C. Navarro ◽  
V. R. Edgerton
Keyword(s):  
Growth Hormone ◽  
Succinate Dehydrogenase ◽  
Cross Sections ◽  
Fiber Type ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Fast Myosin ◽  
Hormone Effect ◽  
Fast Myosin Heavy Chain

The objectives of the present study were to determine the size and enzyme properties of soleus fibers of rats subjected to a 4-day spaceflight (National Aeronautics and Space Administration, STS-41) and the effects of exogenous growth hormone (GH) on the atrophic response of the muscle. Four groups of rats were studied: 1) control (Con), 2) Con plus GH treated (Con + GH), 3) flight (Fl), and 4) F1 plus GH treated (Fl + GH). Cross-sectional area and the activities of succinate dehydrogenase and myofibrillar adenosinetriphosphatase (ATPase) were determined in fibers identified in frozen serial cross sections. Fibers were categorized immunohistochemically as slow, fast, or slow-fast on the basis of their reaction with slow and fast myosin heavy-chain (MHC) monoclonal antibodies. Fibers also were categorized as light or dark on the basis of their staining for ATPase at pH 8.6. After the 4-day flight, mean body weight was significantly decreased compared with control. The absolute and relative (muscle wt/body wt) soleus weights were significantly smaller in the Fl and Fl + GH rats compared with their respective ground-based controls. In both flight groups, the cross-sectional area of the light ATPase fibers was significantly smaller (approximately 30%) than control. Three of 11 flight rats had a higher proportion of fibers expressing both slow and fast MHCs than expected on the basis of the fiber type distribution in the 11 control rats. Mean fiber succinate dehydrogenase and ATPase activities were similar among the four groups.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals The assessment sectional area of stem wood and stocks in experimental trees reclamation Western Donbass plot № 1

2016 ◽  
Vol 45 ◽  
pp. 76-81
Author(s):  
V. M. Zverkovsky ◽  
O. S. Zubkova
Keyword(s):  
Cross Sections ◽  
Linear Growth ◽  
Cross Sectional Area ◽  
Forest Plantations ◽  
Sectional Area ◽  
Cross Sectional ◽  
Stem Wood ◽  
Diameter At Breast Height ◽  
Breast Height

The linear growth of forest plantations of Western Donbass’ recultivating plot №1 were studied. The established cross-sectional the area of trunks and timber reserves experimental trees.Characterized by parameters which are the volume of wood: its height, diameter at breast height and shape of the forming barrel. In diameter at breast height cross sectional area is determined and then the barrel volume is calculated. Cross sections of tree trunks are shaped like a circle or an ellipse. Knowing the volume of logs we calculated reserves of wood for trees experimental plots.The largest reserves of timber and cross-sectional area characterized planting U. pumila – 15,367 m3 and 1,9583 m2, A. platanoides – 13,328 m3 and 2,67 m2, Q. robur – 10,120 m3 and 1,452 m2, J. virginiana – 8,748 m3 and 2,106 m2. The least plantation stocks of wood characterized E. angustifolia – 1,3699 m3 and 0,3693 m2, R. pseudoacacia – 2,9478 m3 and 0,8350 m2, P. rallasiana – 3,1626 m3 and 0,3279 m2.

scholarly journals The assessment sectional area of stem wood and stocks in experimental trees reclamation Western Donbass plot № 1

2016 ◽  
Vol 45 ◽  
pp. 76-81
Author(s):  
V. M. Zverkovsky ◽  
O. S. Zubkova
Keyword(s):  
Cross Sections ◽  
Linear Growth ◽  
Cross Sectional Area ◽  
Forest Plantations ◽  
Sectional Area ◽  
Cross Sectional ◽  
Stem Wood ◽  
Diameter At Breast Height ◽  
Breast Height

The linear growth of forest plantations of Western Donbass’ recultivating plot №1 were studied. The established cross-sectional the area of trunks and timber reserves experimental trees.Characterized by parameters which are the volume of wood: its height, diameter at breast height and shape of the forming barrel. In diameter at breast height cross sectional area is determined and then the barrel volume is calculated. Cross sections of tree trunks are shaped like a circle or an ellipse. Knowing the volume of logs we calculated reserves of wood for trees experimental plots.The largest reserves of timber and cross-sectional area characterized planting U. pumila – 15,367 m3 and 1,9583 m2, A. platanoides – 13,328 m3 and 2,67 m2, Q. robur – 10,120 m3 and 1,452 m2, J. virginiana – 8,748 m3 and 2,106 m2. The least plantation stocks of wood characterized E. angustifolia – 1,3699 m3 and 0,3693 m2, R. pseudoacacia – 2,9478 m3 and 0,8350 m2, P. rallasiana – 3,1626 m3 and 0,3279 m2.

Effects of Volute Cross-Sectional Area Distribution on Performance of Double-Suction Volute Pump

2019 ◽  
Author(s):  
Szu Yung Chen ◽  
Lu Zhang ◽  
Yumiko Sekino ◽  
Hiroyoshi Watanabe
Keyword(s):  
Fluid Dynamics ◽  
Genetic Algorithm ◽  
Computational Fluid Dynamics ◽  
Secondary Flow ◽  
Cross Sections ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Suction Pump ◽  
Computational Fluid Dynamics Cfd

Abstract The following study describes the optimization design procedure of a double-suction pump. BASELINE pump is designed as inlet nozzle diameter 800 mm and impeller outlet diameter 740 mm. Each component of a BASELINE pump, impeller configurations, discharge volute, and the suction casing were determined by DOE (Design of Experiments) and sensitivity analysis. However, finite selected design parameters for each component are mostly restricted to the free surface design of the pump casing. In this study, the optimization method approach along with steady Computational Fluid Dynamics (CFD) is introduced to achieve the high efficiency request of a double-suction pump. To investigate the matching optimization of the impeller and discharge volute at design point, the full parametric geometry of discharge volute was developed referred to the BASELINE shape and Multi-Objective Genetic Algorithm NSGA-II (Non-dominated Sorting Genetic Algorithm II) was used. Optimization result shows that by increasing the volute cross-sectional area from the volute tongue till the circumferential angle 180 deg. provides lower loss. This is due to the improvement achieved for the better distribution of the velocity gradient within the volute. A validated unsteady computational fluid dynamics (CFD) was also employed to investigate the performance difference between optimized volute design and the BASELINE which correlated to the pressure fluctuation and secondary flow behavior inside the cross-sections from 80% to 120% of nominal flow rate. The result shows that the flow distortion in the streamwise direction is stronger with the BASELINE and sensitively affects the operation stability. This is due to the different secondary flow pattern in the cross-sections, hence demonstrating a design direction of desired volute cross-sectional shape for high-performance can be used in a double-suction volute pump.

Normalization of force generated by canine airway smooth muscles

1991 ◽  
Vol 260 (6) ◽  
pp. L522-L529 ◽  
Author(s):  
H. Jiang ◽  
A. J. Halayko ◽  
K. Rao ◽  
P. Cunningham ◽  
N. L. Stephens
Keyword(s):  
Smooth Muscle ◽  
Cross Section ◽  
Cross Sections ◽  
Smooth Muscles ◽  
Muscle Cells ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Muscle Stress ◽  
Total Tissue

A variety of normalizations have been employed to compare maximal isometric force (Po) produced by smooth muscles at different locations and stages of maturation. Because these procedures have not always been based on rigorous principles, confusion has resulted. To obtain a less ambiguous index of force production, we measured in vitro Po from mongrel canine tracheal (TSM) and bronchial (BSM) smooth muscle with an electromagnetic lever and normalized it to force per unit cross-sectional area of whole tissue (tissue stress), to force per unit cross-sectional area of muscle in the cross section of total tissue (muscle stress), and to force per fractional unit of myosin in the tissue cross section (myosin stress). Proportion of myosin in cross-sectional area of tissue was deduced from data obtained by sodium dodecyl sulfate gel electrophoresis of crude muscle extracts. For TSM, tissue stress was 1.499 X 10(5) N/m2 +/- 0.1 (SE), whereas it was only 0.351 X 10(5) N/m2 +/- 0.05 (SE) for BSM, representing a 4.27-fold difference (P less than 0.01). There was a 1.60-fold difference (P less than 0.05) in muscle stress, which was correlated to the morphometric finding that 79 +/- 1.4% (SE) of the tracheal strip cross section was muscle, whereas only 30 +/- 1.0% (SE) of bronchial tissue was occupied by muscle. Average myosin content was the same in smooth muscle cells of TSM and BSM, indicating that total amount of myosin in tissue cross sections was essentially a function of proportional area of muscle cells in total tissue cross sections.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Downstream Morphologic Characteristics of the Alluvial Section of Lower River Ogun, Nigeria

2015 ◽  
Vol 8 (1-2) ◽  
pp. 1-10 ◽  
Author(s):  
Olutoyin A. Fashae ◽  
Adetoye Faniran
Keyword(s):  
Cross Sections ◽  
Morphological Characteristics ◽  
Scientific Basis ◽  
River Channel ◽  
Cross Sectional Area ◽  
Correlation Technique ◽  
Sectional Area ◽  
Cross Sectional ◽  
Wide Range ◽  
Wetted Perimeter

Abstract Rivers constitute an important focus of attention in surface water studies because of their dynamic nature. Therefore, natural rivers develop a wide range of channel forms whose characteristics vary as a function of the position within the fluvial systems. This study examined the river channel morphologic parameters along the alluvial section of River Ogun in South western Nigeria. Data on the channel morphologic variables were collected through field measurement of the bankfull cross sectional characteristics of the river from where the longitudinal characteristics were defined. 48 cross sections were randomly established at bankfull stage along the river channel stretch of 90 km. Bankfull depth and width at each of the cross sections were determined using sonar (electronic sounding machine) that was mounted to a boat. Velocity was measured with the aid of a current meter, while other morphological parameters were estimated from the field data. Analysis of variance revealed that downstream morphological characteristics of the river varies distinctively at each cross section with bedslope as the most significantly varied among all other morphologic parameters (F=91.18; P=0.00). Pearson product moment correlation technique revealed that bankfull width had a correlation of 0.8 and 0.9 with wetted perimeter and cross sectional area respectively while bankfull depth (maximum) had correlations of 0.9, 0.8 and 0.78 with hydraulic radius, wetted perimeter and cross sectional area respectively. The research also revealed that gradient affects the discharge with a positive correlation of 0.9. The study ascertains the extent of variability in the morphologic characteristic of River Ogun which provides scientific basis for river maintenance and management.

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