An investigation into the causes of small scale variation in sediment community oxygen consumption in the Rockall Trough

1986 ◽  
Vol 88 ◽  
pp. 281-290
Author(s):  
J. W. Patching ◽  
R. C. T. Raine ◽  
P. R. O. Barnett
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Small Scale ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Core ◽  
Rockall Trough ◽  
Small Cross Sectional Area

An attempt was made to interpret the core to core variation in oxygen uptake observed during anin situdetermination of sediment community oxygen consumption (SCOC) at a station in the Rockall Trough using the “suspended core” technique. No direct relationships between macrofaunal abundance or biomass and SCOC were observed. The results obtained suggested that the use of experimental chambers of small cross-sectional area (26.2cm2) allow for greater influence on SCOC of the activity of individual organisms which would otherwise be averaged out by larger, grab-type enclosures. The possible significance of other components of the benthos is discussed.

Determination of cross-sectional area of natural plant fibres and fibre failure analysis by in situ SEM observation during microtensile tests

Cellulose ◽  
2019 ◽  
Vol 26 (8) ◽  
pp. 4693-4706 ◽  
Author(s):  
Hangbo Yue ◽  
Juan C. Rubalcaba ◽  
Yingde Cui ◽  
Juan P. Fernández-Blázquez ◽  
Chufen Yang ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Natural Plant ◽  
Fibre Failure ◽  
Sem Observation

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.

Functional significance of compensatory overloaded rat fast muscle

1982 ◽  
Vol 52 (2) ◽  
pp. 473-478 ◽  
Author(s):  
R. R. Roy ◽  
I. D. Meadows ◽  
K. M. Baldwin ◽  
V. R. Edgerton
Keyword(s):  
Biochemical Properties ◽  
Slow Muscle ◽  
Repetitive Stimulation ◽  
Contractile Properties ◽  
Sectional Area ◽  
Shortening Velocity ◽  
Cross Sectional ◽  
Time To Peak ◽  
Isometric Twitch

Chronic overload of a skeletal muscle by removing its synergists produces hypertrophy and marked changes in its metabolic and biochemical properties. In this study alterations in the contractile properties of the plantaris 12–14 wk after bilateral removal of the soleus and gastrocnemius were investigated. In situ isometric and isotonic contractile properties of overloaded plantaris (OP), normal plantaris (NP), and normal soleus (NS) were tested at 33 +/- 1 degree C. Op were 97% heavier than NP and produced 43 and 46% higher twitch (Pt) and tetanic (Po) tensions. However, NP produced more tension per cross-sectional area than OP (mean 26.2 vs. 21.6 N/cm2; P less than 0.001). Isometric twitch time to peak tension (TPT) and half-relaxation time (1/2RT) were significantly longer in OP (mean 36.4 vs. 32.5 ms and 23.9 vs. 18.4 ms). Mean maximum shortening velocity (Vmax, mm/s per 1,000 sarcomeres) were 34.1 for NP and 18.1 for OP (P less than 0.001). The degree of conversion toward the Vmax of NS was 74% compared with only 19 and 14% for TPT and 1/2RT. OP produced a higher proportion of Po at a given stimulation frequency than NP and showed less fatigue than NP after repetitive stimulation. Chronic overload of the fast plantaris modified to varying degrees the contractile properties studied toward that resembling a slow muscle. Although the maximum tension of OP was markedly enhanced it was not in proportion to the increase in muscle mass.

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.

Nasal vestibule wall elasticity: interactions with a nasal dilator strip

1999 ◽  
Vol 86 (5) ◽  
pp. 1638-1643 ◽  
Author(s):  
T. C. Amis ◽  
J. P. Kirkness ◽  
E. di Somma ◽  
J. R. Wheatley
Keyword(s):  
Elastic Properties ◽  
Cross Sectional Area ◽  
Horizontal Direction ◽  
Sectional Area ◽  
Cross Sectional ◽  
Nasal Vestibule ◽  
Wall Displacement ◽  
Recoil Force ◽  
Wall Compliance

We studied the effect of an adhesive external nasal dilator strip (ENDS) on external nasal geometry in 20 healthy Caucasian adults (10 men, 10 women; age 21–45 yr). The recoil force exerted by ENDS was estimated by bending the device ( n = 10) with known weights. In the horizontal direction, a small/medium-sized ENDS in situ exerted a unilateral recoil force of 21.4–22.6 g. Application of ENDS resulted in a displacement of the lateral nasal vestibule walls that had both anterosuperior and horizontal components and that was maintained over an 8-h period. The resultant unilateral nasal vestibule wall displacement at the tip of the device was at 47.6 ± 2.0° to the horizontal (as related to the plane of the device when in situ) and had a magnitude of 3.5 ± 0.1 mm. ENDS increased external nasal cross-sectional area by 23.0–65.3 mm2. Nasal vestibule wall compliance was estimated at 0.05–0.16 mm/g. Thus ENDS applies a relatively constant abducting force irrespective of nasal width. Variable responsiveness to ENDS may be related to differences in elastic properties of the nasal vestibule wall.

The effect of hydrostatic pressure on the Fermi surface of white tin

1979 ◽  
Vol 57 (6) ◽  
pp. 884-889 ◽  
Author(s):  
J. M. Perz ◽  
I. M. Templeton
Keyword(s):  
Hydrostatic Pressure ◽  
Fermi Surface ◽  
Cross Sectional ◽  
Indirect Methods ◽  
Comprehensive Determination ◽  
Shift Technique ◽  
Direct And Indirect Methods ◽  
The Magnetic Field

The derivatives with respect to hydrostatic pressure of 12 extremal cross-sectional areas of the Fermi surface of tetragonal white (β) tin have been measured by the fluid helium de Haas van Alphen phase shift technique. The samples were carefully aligned in situ to have a crystal symmetry axis ([001], [100], or [110]) parallel to the magnetic field. The measured derivatives differ significantly from most values found previously by both direct and indirect methods; it is believed that the present work provides the first reliable comprehensive determination of these quantities. The present experiments also confirm the conclusions of magnetostriction experiments that there is a second orbit normal to [100] on the sixth zone surface not identified in earlier conventional de Haas van Alphen work, and that the third zone extremal areas normal to [001] are larger than previously accepted values determined in de Haas van Alphen studies.

scholarly journals The SCOC database, a large, open, and global database with sediment community oxygen consumption rates

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Tanja Stratmann ◽  
Karline Soetaert ◽  
Chih-Lin Wei ◽  
Yu-Shih Lin ◽  
Dick van Oevelen
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Selection Procedure ◽  
Ex Situ ◽  
Global Database ◽  
Data Record ◽  
Consumption Rates ◽  
Meta Analyses

Abstract Sediment community oxygen consumption (SCOC) rates provide important information about biogeochemical processes in marine sediments and the activity of benthic microorganisms and fauna. Therefore, several databases of SCOC data have been compiled since the mid-1990s. However, these earlier databases contained much less data records and were not freely available. Additionally, the databases were not transparent in their selection procedure, so that other researchers could not assess the quality of the data. Here, we present the largest, best documented, and freely available database of SCOC data compiled to date. The database is comprised of 3,540 georeferenced SCOC records from 230 studies that were selected following the procedure for systematic reviews and meta-analyses. Each data record states whether the oxygen consumption was measured ex situ or in situ, as total oxygen uptake, diffusive or advective oxygen uptake, and which measurement device was used. The database will be curated and updated annually to secure and maintain an up-to-date global database of SCOC data.

A Facile In-Situ Development of L-Valine Film onto the Surface of Carbon Paste Electrode Towards the Detection of Environmentally Hazardous 4-Amino Phenol

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
T. Venu Gopal ◽  
Tukiakula Madhusudana Reddy ◽  
P. Shaikshavali ◽  
G. Venkataprasad ◽  
P. Gopal
Keyword(s):  
Cyclic Voltammetry ◽  
Carbon Paste Electrode ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Small Scale ◽  
Carbon Paste ◽  
Relative Standard ◽  
Paste Electrode

Abstract A small scale of environmentally hazardous 4-aminophenol can show significant impact on human health. Hence, in the present work, we have designed L-Valine film (Vf) modified carbon paste electrode (Vf/CPE) for the determination of 4-aminophenol. Herein, a facile in-situ L-Valine film was developed by electrochemical polymerization method onto the surface of bare carbon paste electrode (BCPE) with the help of cyclic voltammetry (CV) technique. A two-folds of electrochemical peak current enhancement was achieved at Vf/CPE in comparison with BCPE towards the determination of 4-aminophenol in optimum pH 7.0 of phosphate buffer solution (PBS). This was achieved due to the large surface area and conductive nature of Vf/CPE, which was concluded through the techniques of cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The effect of pH of buffer and scan rate studies were successfully studied. Morphological changes of BCPE and Vf/CPE was studied with the help of scanning electron microscopy (SEM). The formation of Vf on CPE was also analyzed by Fourier transform infrared (FTIR) spectra. Under the optimized conditions, the limit of detection (LOD) and limit of quantification (LOQ) values of 4-aminophenol were estimated with the aid of chronoamperometry (CA) technique and was found to be 9.8 μM and 32 μM, respectively. Finally the proposed method was found to have satisfactory repeatability, reproducibility and stability results with low relative standard deviation (RSD) values.

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