scholarly journals Analisis Potensi Pembangkit Listrik Tenaga Mikro Hydro Pada Anak Sungai di Bulungan

2021 ◽  
Vol 4 (1) ◽  
pp. 61-66
Author(s):  
Dady Sulaiman ◽  
Wibowo Romadhoni ◽  
Purnama Purnama
Keyword(s):  
Renewable Energy ◽  
Data Collection ◽  
Flow Velocity ◽  
River Flow ◽  
Electrical Energy ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Remote Areas ◽  
Fall Height

ABSTRAK Energi listrik merupakan energi utama masyarakat pada era globalisasi. Perusahaan Listrik Nasional (PLN) masih belum bisa menjangkau daerah – daerah terpencil khususnya daerah kabupaten Bulungan yang memiliki banyak daerah terpencil. Masalah ini dapat diatasi dengan memanfaatkan anak sungai yang ada di kabupaten Bulungan sebagai sumber energi listrik. Penelitian ini dimulai dengan survey memilih 20 titik anak sungai yang akan diteliti di kabupaten Bulungan. Selanjutnya pengambilan data yaitu luas penampang sungai, kecepatan aliran sungai, dan tinggi jatuh air. Data ini akan dianalisis dengan menggunakan rumus agar memperoleh nilai daya teoritis yang dihasilkan oleh masing – masing sungai yang telah ditentukan. Hasil penelitian inimenunjukkan diantara 20 anak sungai yang diteliti hanya 2 anak sungai yang memiliki potensi yaitu sungai 9 dengan daya 5,5 kW dan sungai 14 dengan daya 8,5 kW. Hasil penelitian ini dapat dikembangkan lagi agar dapat bermanfaat bagi pengembangan daerah – daerah terpencil yang tidak terjangkau PLN. Kata kunci : Daya, Energi Terbarukan, PLTMH ABSTRACT Electrical energy is the main energy of society in the era of globalization. Perusahaan Listrik Nasional (PLN) is still unable to reach remote areas, especially the Bulungan district which has many remote areas. This problem can be overcome by utilizing tributaries in Bulungan district as a source of electrical energy. This research began with a survey selecting 20 tributary points to be studied in Bulungan district. Furthermore, data collection was the cross-sectional area of the river, river flow velocity, and water fall height. This data was  analyzed using a formula in order to obtain the theoretical power value generated by each predetermined river. The results of this study indicatde that among the 20 tributaries studied, only 2 tributaries have potential, namely river 9 with a power of 5.5 kW and river 14 with a power of 8.5 kW. It is hoped that the results of this research can be further developed so that they can be useful for the development of remote areas that are not reached by PLN. Keyword: PLTMH, Power,  Renewable Energy

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 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

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.

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