scholarly journals Depth of tillage and its effect on field watershed size in Ejigbo zone, Osun State, Nigeria

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Wasiu Agunbiade Lamidi ◽  
Wasiu Agunbiade Lamidi ◽  
Wasiu Agunbiade Lamidi ◽  
Wasiu Agunbiade Lamidi ◽  
Adedamola Emmanuel Olawumi ◽  
...  
Keyword(s):  
Zea Mays ◽  
Flow Velocity ◽  
Sectional Area ◽  
Runoff Water ◽  
Cross Sectional ◽  
Maize Hybrids ◽  
M 10 ◽  
Different Depths ◽  
Wetted Perimeter ◽  
Lower Depth

The study investigated effects of different depths of tillage on flow of runoff in watersheds on fields tilled and planted with maize (Zea mays) hybrids and open pollinated variety (OPV) of maize. Twelve 1 m × 1 m × 2 m pits were dug and overlaid at all sides and at its bottom with impermeable membrane to accumulate watershed’s runoff from the fields. Twelve compartmental plots of 400 m2 each comprising 2 depths of tillage (0-15 cm and 0-30 cm) and 2 varieties of maize (hybrids and open pollinated) were used. Each of the treatments was replicated thrice to make 2 × 2 × 3 factorial design. Each plot measured 4 m × 10 m at 2 m apart. Among the data collected were the volume of water accumulated in the small earthen pits dug, flow velocity (v m/s) of water in runoff channels/collectors that fed earthen pits, slopes of the collectors, cross-sectional area of collectors and wetted perimeter. Results revealed that average infiltrometer values of 15.00±0.24 mm/h and 16.50±0.40 mm/h respectively in the upper part and the lower part were recorded. The 0-15 cm depth of tillage accumulated more volume of runoff water than the 0-30 cm depth of tillage in the pits and it was 23.33% higher in the lower depth of tillage used on the field than the 0-30 cm depth of tillage. Implying that 0-30 cm tillage depth retained more water from the rainfall compare to the water retained by the 0-15 cm depth. Even though, volume of runoff water of 0-15 cm depth of tillage was higher than that of the 0-30 cm depth of tillage, 0-15 cm depth of tillage had the highest yield of maize (9.30±4.26 t ha-1).

scholarly journals A Study of Sedimentation at the River Estuary on the Change of Reservoir Storage

2018 ◽  
Vol 31 ◽  
pp. 03001 ◽  
Author(s):  
Iskahar ◽  
Suripin ◽  
Isdiyana
Keyword(s):  
Flow Velocity ◽  
Water Level ◽  
Physical Model ◽  
River Estuary ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Sedimentation Pattern ◽  
Cross Sectional ◽  
Channel Angle ◽  
Reservoir Storage

Estuary of the river that leads to the reservoir has characteristics include: relatively flat, there is a change in the increase of wet cross-sectional area and backwater. The backwater will cause the flow velocity to be reduced, so that the grains of sediment with a certain diameter carried by the flow will settle in the estuary of the river. The purpose of this research is to know the distribution and sedimentation pattern at the river estuary that leads to the reservoir with the change of water level in the reservoir storage, so the solution can be found to remove / reduce sediment before entering the reservoir. The method used is the experimental, by making the physical model of the river estuary leading to the reservoir. This study expects a solution to reduce sedimentation, so that sedimentation can be removed / minimized before entering the reservoir. This research tries to apply bypass channel to reduce the sedimentation at the river estuary. Bypass channels can be applied to overcome sedimentation at the river estuary, but in order for the sediment to be removed optimally, it is necessary to modify the mouth of bypass channel and channel angle.

Effect of endurance training on coronary artery size and function in healthy men: an invasive followup study

2002 ◽  
Vol 282 (6) ◽  
pp. H2216-H2223 ◽  
Author(s):  
Stephan Windecker ◽  
Yves Allemann ◽  
Michael Billinger ◽  
Tilmann Pohl ◽  
Damian Hutter ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Oxygen Uptake ◽  
Flow Velocity ◽  
Coronary Flow ◽  
Exercise Program ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Coronary Flow Velocity Reserve ◽  
Cross Sectional ◽  
Coronary Flow Velocity

In eight healthy male volunteers (cardiologists; age 36 ± 5 yr), bicycle spiroergometry, Doppler echocardiography, and quantitative coronary angiography with intracoronary Doppler measurements before and after completion of a physical endurance exercise program of >5 mo duration were performed. Maximum oxygen uptake increased from 46 ± 6 to 54 ± 5 ml · kg−1 · min−1( P = 0.04), maximum ergometric workload changed from 3.8 ± 0.3 to 4.4 ± 0.3 W/kg ( P = 0.001), and left ventricular mass index increased from 82 ± 18 to 108 ± 29 g/m2 ( P = 0.001). The right, left main, and left anterior descending coronary artery cross-sectional area increased significantly in repsonse to exercise. Before versus at the end of the exercise program, flow-induced left anterior descending coronary artery cross-sectional area was 10.1 ± 3.5 and 11.0 ± 3.9 mm2, respectively ( P = 0.03), nitroglycerin-induced left coronary calibers increased significantly, and coronary flow velocity reserve changed from 3.8 ± 0.8 to 4.5 ± 0.7 ( P = 0.001). Left coronary artery correlated significantly with ventricular mass and maximum oxygen uptake, and coronary flow velocity reserve was significantly associated with maximum workload.

Left atrial cross-sectional area is a novel measure of atrial shape associated with cardioembolic strokes

Heart ◽  
2020 ◽  
Vol 106 (15) ◽  
pp. 1176-1182
Author(s):  
Timothy C Tan ◽  
Maria Carmo Pereira Nunes ◽  
Mark Handschumacher ◽  
Octavio Pontes-Neto ◽  
Yong-Hyun Park ◽  
...  
Keyword(s):  
Ischaemic Stroke ◽  
Flow Velocity ◽  
Left Atrial ◽  
Velocity Profiles ◽  
Left Ventricular ◽  
Cross Sectional Area ◽  
Left Ventricular Ejection ◽  
Sectional Area ◽  
Cross Sectional

ObjectiveCardioembolic (CE) stroke carries significant morbidity and mortality. Left atrial (LA) size has been associated with CE risk. We hypothesised that differential LA remodelling impacts on pathophysiological mechanism of major CE strokes.MethodsA cohort of consecutive patients hospitalised with ischaemic stroke, classified into CE versus non-CE strokes using the Causative Classification System for Ischaemic Stroke were enrolled. LA shape and remodelling was characterised by assessing differences in maximal LA cross-sectional area (LA-CSA) in a cohort of 40 prospectively recruited patients with ischaemic stroke using three-dimensional (3D) echocardiography. Flow velocity profiles were measured in spherical versus ellipsoidal in vitro models to determine if LA shape influences flow dynamics. Two-dimensional (2D) LA-CSA was subsequently derived from standard echocardiographic views and compared with 3D LA-CSA.ResultsA total of 1023 patients with ischaemic stroke were included, 230 (22.5%) of them were classified as major CE. The mean age was 68±16 years, and 464 (45%) were women. The 2D calculated LA-CSA correlated strongly with the LA-CSA measured by 3D in both end-systole and end-diastole. In vitro flow models showed shape-related differences in mid-level flow velocity profiles. Increased LA-CSA was associated with major CE stroke (adjusted relative risk 1.10, 95% CI 1.04 to 1.16; p<0.001), independent of age, gender, atrial fibrillation, left ventricular ejection fraction and CHA2DS2-VASc score. Specifically, the inclusion of LA-CSA in a model with traditional risk factors for CE stroke resulted in significant improvement in model performance with the net reclassification improvement of 0.346 (95% CI 0.189 to 0.501; p=0.00001) and the integrated discrimination improvement of 0.013 (95% CI 0.003 to 0.024; p=0.0119).ConclusionsLA-CSA is a marker of adverse LA shape associated with CE stroke, reflecting importance of differential LA remodelling, not simply LA size, in the mechanism of CE risk.

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.

scholarly journals SIMULASI LUAS PENAMPANG STREET INLET JALAN YOS SUDARSO KOTA PALANGKA RAYA

2021 ◽  
Vol 10 (1) ◽  
pp. 40-48
Author(s):  
I Made Kamiana
Keyword(s):  
Water Depth ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Road ◽  
M 10 ◽  
Design Discharge ◽  
The Cross ◽  
On The Road ◽  
The Relationship

Abstract: The inaccurate of cross-sectional area of the street inlet can be one of the flooding causes on the road surface when the rainfall intensity is very high. This study aims to simulate the relationship between the cross-sectional area of the street inlet and the street inlet distance at Jalan Yos Sudarso, Palangka Raya City. The length of the reviewed road is 0.5 km. The simulation using an analytical approach. In the simulation, the street inlet distance variations are 5 m, 10 m, and 20 m; variations of the design discharge return period are 2 years, 5 years, and 10 years; variations of design water depth in the gutter are 1 cm, 1.5 cm, and 2 cm. The results show, the cross-sectional area of street inlet is getting bigger if the street inlet distance is getting bigger. At each street inlet distance, the cross-sectional area of street inlet is directly proportional to the design discharge and inversely proportional to the design water depth in the gutter. The cross-sectional area of street inlet at the street inlet distance of 5 m ranges from 62.72 to 284.42 m2, at the street inlet distance of 10 m ranges from 177.84 to 498.29 m2, and at the street inlet distance of 10 m ranges from 345.41 to 809.62 m2.Keywords : street inlet, cross-sectional area, street inlet distance, design discharge, gutterAbstrak: Tidak tepatnya luas penampang street inlet dapat menjadi salah satu penyebab genangan di permukaan jalan ketika hujan lebat. Penelitian ini bertujuan untuk mensimulasikan hubungan luas penampang street inlet dengan jarak street inlet. Jalan yang ditinjau adalah Jalan Yos Sudarso Kota Palangka Raya. Panjang jalan yang ditinjau 0,5 km. Simulasi dilakukan secara analitis. Dalam simulasi tersebut, variasi jarak street inlet yaitu 5 m, 10 m, dan 20 m; variasi periode ulang debit rencana yaitu 2 tahun, 5 tahun, dan 10 tahun; variasi kedalaman air rencana di saluran pembawa yaitu: 1 cm, 1,5 cm, dan 2 cm. Dari hasil simulasi diketahui luas penampang street inlet semakin besar apabila jarak street inlet semakin besar. Pada setiap jarak street inlet, luas penampang street inlet berbanding lurus dengan debit rencana dan berbanding terbalik dengan kedalaman air rencana di saluran pembawa. Luas penampang street inlet pada jarak street inlet 5 m berkisar antara 62,72-284,42 m2, pada jarak street inlet 10 m berkisar antara 177,84-498,29 m2, dan pada jarak street inlet 20 m berkisar antara 345,41-809,62 m2.Kata kunci : luas penampang street inlet, jarak steet inlet, debit rencana, saluran pembawa

scholarly journals Analysis of the Effect of Cross-sectional Area on Water Flow Velocity by Using Venturimeter Tubes

2020 ◽  
Vol 8 (1) ◽  
pp. 94-99
Author(s):  
Ana Dhiqfaini Sultan ◽  
Rizky Rizky ◽  
Hidayat Hidayat ◽  
Sri Mulyani ◽  
Wahdah Anugrah Yusuf
Keyword(s):  
Flow Velocity ◽  
Water Level ◽  
Water Flow ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Water Flow Velocity ◽  
Heavy Medium ◽  
Air Flow Velocity ◽  
Analyze Data

This simple experiment with title  the analysis of the effect of cross-sectional area on air flow velocity using a venturimeter tube with aim to know the relation between section wide, speed of water flow and water level in capillary pipes and to know basic principle of Bernoulli and the application in simple set. The activity was reading water level of capillary pipes the caused by changes of water flow that started from heavy, medium, and low. Then analyzed the data that got for every changes of water flow that started from count the different water level in capillary pipes on big pipes and small pipes after that looking for speed of fluid flow on both pipes. Based on analyze data as a result relation between section wide, speed of water flow and water level in capillary pipes that was as bigger of section wide then the speed of water flow was getting smaller and the level water in capillary pipes was getting taller. This is appropriate with Bernoulli principle that states an increase in the speed of a fluid on a pipe with decrease in pressure and in reverse.Keywords: Venturimeter Tube, Cross-Sectional Area, Speed Of Water Flow, Water Level, Principle Of BernoulliEksperimen sederhana ini berjudul analisis pengaruh luas penampang terhadap kecepatan aliran air dengan menggunakan Tabung Venturimeter yang bertujuan untuk mengetahui hubungan antara luas penampang, Kecepatan aliran air dan ketinggian air pada pipa kapiler serta untuk mengetahui prinsip dasar hukum Bernoulli dan penerapannya dalam rangkaian sederhana. Kegiatan yang dilakukan adalah membaca ketinggian air pipa kapiler yang disebabkan dari perubahan laju aliran air dimulai dari deras, sedang dan rendah. Kemudian menganalisis data yang diperoleh untuk setiap perubahan laju aliran air yang dimulai dari menghitung perbedaan ketinggian air pipa kapiler pada pipa besar dan pipa kecil setelah itu mencari kecepatan aliran fluida pada kedua pipa. Berdasarkan analisis data diperoleh hubungan antara luas penampang, kecepatan aliran air dan ketinggian air pada pipa kapiler yakni semakin besar luas penampang pipa maka kecepatan aliran air pada pipa semakin kecil dan ketinggian air pada pipa kapiler semakin tinggi. Hal ini sesuai dengan bunyi asas Bernoulli yang menyatakan bahwa semakin besar kecepatan fluida dalam suatu pipa maka tekanannya makin kecil dan sebaliknya makin kecil kecepatan fluida dalam suatu pipa maka semakin besar tekanannya.Kata kunci: Tabung Venturimeter, Luas Penampang, Kecepatan aliran air, Ketinggian air, hukum Bernoulli

Determinants of coronary blood flow in humans: quantification by intracoronary Doppler and ultrasound

2005 ◽  
Vol 98 (3) ◽  
pp. 1076-1082 ◽  
Author(s):  
Heinrich Wieneke ◽  
Clemens von Birgelen ◽  
Michael Haude ◽  
Holger Eggebrecht ◽  
Stefan Möhlenkamp ◽  
...  
Keyword(s):  
Blood Flow ◽  
Flow Velocity ◽  
Coronary Flow ◽  
Left Ventricular ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Lumen Area ◽  
Cross Sectional ◽  
Coronary Flow Velocity ◽  
Intracoronary Doppler

The direct determinants of coronary flow are lumen area and blood flow velocity; however, the precise mechanisms that control these factors are not fully understood. The aim of the present study was to assess by which mechanisms lumen area and coronary flow velocity interact with hemodynamic and morphometric factors, thereby influencing coronary flow. Intracoronary Doppler and ultrasound measurements were performed in 28 patients without coronary lumen irregularities. Flow velocity and lumen cross-sectional area were measured in the proximal segments of all three coronary arteries. Global lumen cross-sectional area and global flow were obtained by adding up the values of all three coronary arteries. Left ventricular mass was assessed by echocardiography. Stress-mass-heart rate and pressure-rate products reflecting myocardial oxygen demand were calculated. Global coronary flow increased during adenosine-induced hyperemia from 197 ± 72 to 637 ± 204 ml/min ( P < 0.001). Global coronary flow closely correlated with the stress-mass-heart rate product ( r = 0.62; P < 0.001). Looking at the two constituents of flow separately, global coronary cross-sectional area was closely related to left ventricular muscle mass ( r = 0.61; P < 0.001), whereas mean coronary flow velocity at rest showed a strong linear relation with the pressure-rate product ( r = 0.64; P < 0.001). There was no interaction between cross-sectional area and blood flow velocity in any of the coronary vessels. Coronary lumen size and flow velocity, the two determinants of coronary flow, are principally determined by different physiological factors. Long-term flow adaptation is achieved by an increase in coronary lumen size, whereas short-term myocardial oxygen requirements are met by changes in resting flow velocity.

scholarly journals The contributions of arterial cross-sectional area and time-averaged flow velocity to arterial blood flow

2018 ◽  
Vol 26 (4) ◽  
pp. 186 ◽  
Author(s):  
EthanC Hill ◽  
TerryJ Housh ◽  
CoryM Smith ◽  
JoshuaL Keller ◽  
RichardJ Schmidt ◽  
...  
Keyword(s):  
Blood Flow ◽  
Flow Velocity ◽  
Cross Sectional Area ◽  
Arterial Blood Flow ◽  
Sectional Area ◽  
Cross Sectional ◽  
Arterial Blood
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