scholarly journals Error analysis of hydraulic radius evaluation in hydraulic calculation

2021 ◽  
Vol 260 ◽  
pp. 03016
Author(s):  
Ye Yin ◽  
Dangwei Wang ◽  
Hantao Wang ◽  
Anjun Deng ◽  
Shenghang Feng
Keyword(s):  
Cross Section ◽  
Water Depth ◽  
Hydraulic Calculation ◽  
Hydraulic Radius ◽  
Rectangular Section ◽  
Cross Sectional ◽  
Water Level Changes ◽  
Average Water ◽  
Cross Sectional Average ◽  
Natural Rivers

Hydraulic radius is an important parameter in hydraulic calculation. It is often deemed that hydraulic radius can be replaced by the cross-sectional average water depth when the width to depth ratio (B/H) is greater than a certain value in traditional. Based on the various artificial cross-section and natural ones, value-taking errors of hydraulic radius are studied in this paper. The results show that it is feasible to adopt the average water depth as the hydraulic radius when B/H of rectangular section is larger than 40 or B/H of isosceles triangular section is larger than 12. But for natural river, B/H is different when water level changes and there is no single-valued corresponding relationship between relative error and B/H. Therefore, we advise that hydraulic radius could not be replaced by other variables in hydraulic calculation of natural rivers.

Simulasi Perancangan Drainase Muka Tanah pada Bandar Udara Achmad Yani Semarang Sebagai Salah Satu Usaha Pencegahan Banjir

WARTA ARDHIA ◽  
2013 ◽  
Vol 39 (4) ◽  
pp. 305-316
Author(s):  
Ataline Muliasari ◽  
Lupi Wahyuningsih
Keyword(s):  
Surface Water ◽  
Cross Section ◽  
Land Surface ◽  
Drainage Channel ◽  
Water Drainage ◽  
Hydraulic Radius ◽  
Channel Depth ◽  
Cross Sectional ◽  
Surface Drainage ◽  
Sectional Shape

Drainage is defined as surface water drainage, either by gravity or by pump which aims to prevent inundation, maintain and lower the water level im order to avoid the amount of water. Ahmad Yani Airport has a poor drainage systems. Furthermore, land subsidence in Semarang area potential for experiencing flooding when the rainy season with a fairly high rainfall. Based on the results of processing the data showed that it is needed the land surface drainage channel with a cross-sectional shape of a trapezium. When the width of the base of the cross section is 3 meters , then the required channel depth is 3.9 meters with a hydraulic radius is 0.82-meter, and hydraulic depth is 3.05 meters. Drainase didefinisikan sebagai pembuangan air permukaan, baik secara gravitasi maupun dengan pompa yang bertujuan untuk mencegah terjadinya genangan, menjaga dan menurunkan permukaan air sehingga genangan air dapat dihindarkan. Bandar Udara Ahmad Yani dengan kondisi sistem drainase yang kurang baik dan penurunan permukaan tanah di wilayah Semarang, maka bila musim penghujan tiba dengan curah hujan yang cukup tinggi selalu berpotensi untuk mengalami banjir. Berdasarkan hasil pengolahan data juga didapatkan hasil bahwa untuk menyesuaikan antara curah hujan di wilayah Semarang dengan luas area Bandar udara Achmad Yani diperlukan saluran drainase muka tanah berupa saluran dengan bentuk penampang trapezium. Bila lebar dasar dari penampang trapezim tersebut adalah 3 meter, maka diperlukan saluran sedalam 3,9 meter dengan Jari-jari hydraulic 0,82 meter, dan kedalaman hydraulic 3,05 meter.

scholarly journals TO A QUESTION OF DETERMINATION OF HYDRAULIC RADIUS OF A BACKFILL FLOW FOR THE EXCENTRATIVE PLACEMENT OF PIPES IN DRILLING BORE

2018 ◽  
pp. 197-209
Author(s):  
V. M. Moishyshyn ◽  
Y. S. Biletskii ◽  
V. V. Vryukalo ◽  
M. V. Seniushkovych
Keyword(s):  
Cross Section ◽  
Dimensionless Parameter ◽  
Internal Surface ◽  
Outer Radius ◽  
Hydraulic Radius ◽  
Cross Sectional ◽  
Internal Radius ◽  
First Time ◽  
Good Agreement

The processes of displacement of drilling clay backfill flow from the intertubular space formed by internal surface of external and external surfaces of inner tubes are considered. In case of eccentric placement of pipes it is proposed in the form of a cross-section of the flow of a backfill to take the area limited from the outside by the Pascal's snail, and from the inside - the outer surface of the inner pipe at the first time. The formulas for determining areas of the cross section of the flow and the stagnant zone, the perimeter and the hydraulic radius of the section ofthe flow for the eccentric placement of the pipes in the bore are proposed. The dimensionless parameter α is introduced as the ratio of the centripetal distance to difference between internal radius of outer pipe and outer radius of inner tube. It was found that with increasing of α cross-sectional area and their hydraulic radii are increasing, and the area of stagnant zones decreases according to parabolic laws.It is established that with the growth of α velocity of the backfill flow decreases according to parabolic laws and their values are in good agreement with the experimental data.

The flow of a plastic material in ducts

1980 ◽  
Vol 45 (9) ◽  
pp. 2510-2515 ◽  
Author(s):  
Kamil Wichterle ◽  
Ondřej Wein
Keyword(s):  
Cross Section ◽  
Plastic Material ◽  
Kinematics And Dynamics ◽  
Sectional Area ◽  
Hydraulic Radius ◽  
Cross Sectional ◽  
Pressure Losses ◽  
Total Cross Sectional Area ◽  
Flowing Material ◽  
The Cross

The kinematics and dynamics of the flow of an ideally plastic material is fully characterized by the cross section occupied by the flowing material. It will be shown that appart from the case when the flowing material occupies the total cross sectional area of the duct, nontrivial cases exist with part of the cross section occupied by a stagnant material adhering to the walls. For the calculation of pressure losses it is then usefull to characterize the cross section of the duct by the value of the maximum hydraulic radius.

Geometric Design of Rectangular Cross-Sectional Springs

2018 ◽  
Vol 920 ◽  
pp. 126-131
Author(s):  
Yeong Maw Hwang ◽  
D.S. Lin ◽  
Sheng Liang Lin
Keyword(s):  
Shear Stress ◽  
Cross Section ◽  
Maximum Shear Stress ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Rectangular Section ◽  
Cross Sectional ◽  
Short Side ◽  
The Cross ◽  
Sectional Shape

In order to study the influence of the cross-sectional shape on the stiffness of a spring, a finite element analysis software DEFORM is used to simulate and analyze the torsion of rectangular cross-section bars. The material of the bar is TS1800 SAE9254 and the cross-section of aspect ratio (w / h) is 1.5. From literature it is known that when the rectangular section bar is twisted, the shear stress at the four corners is zero, so elliptical corners can decrease the volume and increase the stiffness with the same volume. Five levels for the long side of the elliptical corner are set as 1 to 5 mm, and 3 levels are set for the short side. Torsion of the rectangular section bars under 15 kinds of geometric designs are simulated to find the preferred cross-sectional shape design by evaluating the cross-sectional area, load, and the maximum shear stress. The objective of the design is obtaining a uniform stress distribution with a larger spring stiffness and lighter weight. The optimal cross section of the bars is established as the spring geometry, and the pre-loading processing of the spring is simulated. The required load and the maximum shear stress data are obtained. The effects of load, cross-sectional area and maximum shear stress on the springs performance are investigated.

scholarly journals Two Calving Laws for Grounded Iceberg-Calving Glaciers (Abstract only)

1983 ◽  
Vol 4 ◽  
pp. 295 ◽  
Author(s):  
C. S. Brown ◽  
W. G. Sikonia ◽  
Austin Post ◽  
L. A. Rasmussen ◽  
M. F. Meier
Keyword(s):  
Water Depth ◽  
Variance Reduction ◽  
Coefficient Of Determination ◽  
Time Intervals ◽  
Cross Sectional ◽  
Glacial Stream ◽  
Iceberg Calving ◽  
Average Water ◽  
Image Position ◽  
Best Fit

Prediction of the future retreat of Columbia Glacier, Alaska, required a calving law for the boundary condition at the terminus. Qualitative observations on the variations of all major iceberg-calving glaciers of Alaska suggest that calving is high whenever glaciers terminate in deep water, and greatly reduced whenever they terminate in shallow water. Calving relations were investigated based on calculations of calving speed, defined as the volume rate of iceberg discharge from the terminus divided by the cross-sectional area of the terminus. The calving speed was determined for 12 glaciers for which measurements of glacier speed, advance and retreat rates, and other variables were obtained. To extend the range of data, four additional periods of rapid retreat were examined. Values for the terminus characteristics of water depth, cliff height, and thickness of the terminus, averaged over the width of the glacier and over a year, were then examined in relation to the calculated speeds of calving. A statistical analysis to determine the form and coefficients of an empirical calving relation that approximates the data shows that calving speed is best fitted by a simple proportionality to average water depth at the terminus: 1 where v c is the calving speed and h w the water depth, both averaged over the width and over a year, and c a constant of proportionality. This gives a variance reduction fraction (similar to the coefficient of determination r2) of 0.90. To investigate seasonal changes in calving, data based on shorter time intervals were obtained at the head of embayments from Columbia Glacier. At intervals of approximately two months, the following expression fits intra-yearly calving at Columbia Glacier: 2 where D is the meltwater discharge from the glacier, hj is the height of the ice column unsupported by water buoyancy, a, b, c are constants, and vc and hu are evaluated at the embayment head. D was determined by correlation with a nearby glacial stream, and hu = h _ hw PW/PJ, where h is glacier thickness and pi and pw the densities of ice and water. Best-fit values of b and c are approximately 0.5 and -2, respectively. This yields a variance reduction fraction r2 of 0.83. Equation (2) does not fit data averaged over a year and over the width of the glacier and Equation (1) does not fit data obtained over shorter periods at the head of the embayment. Although the two equations are different in form, for similar or average values of D and h - hw (ice-cliff height), they give approximately similar results over the present range of the geometry of the terminus of Columbia Glacier. Whether this will be true after rapid retreat begins remains to be seen.

Karakteristik Fisik, Kimia, Dan Biologi Tempat Perindukan Potensial Larva Anopheles Sp. Dan Indeks Habitat Di Desa Sukamaju Kecamatan Punduh Pidada Kabupaten Pesawaran

2021 ◽  
Vol 1 (2) ◽  
pp. 122-133
Author(s):  
Akmal Taher ◽  
Tusy Triwahyuni ◽  
Ismalia Husna ◽  
Devita Febriani
Keyword(s):  
Water Depth ◽  
Sampling Site ◽  
Physical Characteristics ◽  
Biological Characteristics ◽  
Water Salinity ◽  
Chemical Characteristics ◽  
Cross Sectional ◽  
Physical Chemical ◽  
Average Water ◽  
Breeding Place

ABSTRACT: PHYSICAL, CHEMICAL, AND BIOLOGICAL CHARACTERISTICS OF POTENTIAL FARMING PLACE OF LARVA Anopheles sp. AND HABITAT INDEX IN SUKAMAJU VILLAGE DISTRICT PUNDUH PIDADA PESAWARAN DISTRICT Background:  Malaria is an infectious disease transmitted through mosquitoes and has become a health problem both in the world and Indonesia especially in Lampung. The population of the malaria vector is strongly influenced by the location of the breeding place. Purpose: Knowing the Physical, Chemical, and Biological Characteristics of Potential Breeding Places for Anopheles Sp. and Habitat Index in Sukamaju Village, Punduh District, Pesawaran Regency, Lampung Province, 2020. Methods: This was a descriptive study with a cross-sectional study research design. The physical characteristics have done by measuring temperature and water depth, the chemical characteristics by measuring pH and water salinity, and the biological characteristics by looking at organisms found at the sampling site. As well as calculating the habitat index. Results: The physical characteristics of the brooding sites have an average water temperature of 31.33 ° C and an average water depth of 25.840 cm. Chemical characteristics of brooding sites mean 2.4280 ‰ of water salinity, and most of the acidity (pH) of water is acidic. The biological characteristics of breeding sites are mostly water and plant predators. Habitat index obtained a value of 1%.Conclusion: That these places have the potential to transmit malaria. Keywords: Anopheles sp., breeding place, malaria   INTISARI: KARAKTERISTIK FISIK, KIMIA, DAN BIOLOGI TEMPAT PERINDUKAN POTENSIAL LARVA Anopheles sp. DAN INDEKS HABITAT DI DESA SUKAMAJU  KECAMATAN PUNDUH PIDADA KABUPATEN PESAWARAN  Latar Belakang : Malaria merupakan penyakit infeksi yang ditularkan melalui nyamuk dan telah menjadi masalah kesehatan baik di dunia maupun di Indonesia khususnya di daerah Lampung. Populasi vektor malaria sangat dipengaruhi oleh lokasi tempat perindukannya. Tujuan : Mengetahui Karakteristik Fisik, Kimia, dan Biologi Tempat Perindukan Potensial Nyamuk Anopheles Sp. dan Indeks Habitat Di Desa Sukamaju Kecamatan Punduh Kabupaten Pesawaran Provinsi Lampung Tahun 2020. Metode : Jenis penelitian ini merupakan penelitian deskriptif dengan pendekatan cross sectional. Karakteristik fisik dilakukan dengan mekukur suhu dan kedalaman air, karakteristik kimia dengan mengukur pH dan salinitas air, dan karakteristik biologi dengan melihat organisme yang ditemukan di tempat pengambilan sampel. Serta melakukan penghitungan indeks habitat. Hasil : Karakteristik fisik pada tempat perindukan rata-rata suhu air 31,33°C, dan rata-rata kedalaman air 25,840 cm. Karakteristik Kimia pada tempat perindukan rata-rata salinitas air 2,4280‰, dan sebagian besar derajat keasaman (pH) air adalah asam. Karakteristik Biologi pada tempat perindukan sebagian besar terdapat predator air dan tumbuhan. Indeks habitat didapatkan nilai 1%. Kesimpulan : Bahwa tempat-tempat tersebut berpotensi untuk penularan penyakit malaria. Kata Kunci : Anopheles sp., malaria, tempat perindukan

scholarly journals Two Calving Laws for Grounded Iceberg-Calving Glaciers (Abstract only)

1983 ◽  
Vol 4 ◽  
pp. 295-295 ◽  
Author(s):  
C. S. Brown ◽  
W. G. Sikonia ◽  
Austin Post ◽  
L. A. Rasmussen ◽  
M. F. Meier
Keyword(s):  
Water Depth ◽  
Variance Reduction ◽  
Coefficient Of Determination ◽  
Time Intervals ◽  
Cross Sectional ◽  
Glacial Stream ◽  
Iceberg Calving ◽  
Average Water ◽  
Image Position ◽  
Best Fit

Prediction of the future retreat of Columbia Glacier, Alaska, required a calving law for the boundary condition at the terminus. Qualitative observations on the variations of all major iceberg-calving glaciers of Alaska suggest that calving is high whenever glaciers terminate in deep water, and greatly reduced whenever they terminate in shallow water. Calving relations were investigated based on calculations of calving speed, defined as the volume rate of iceberg discharge from the terminus divided by the cross-sectional area of the terminus. The calving speed was determined for 12 glaciers for which measurements of glacier speed, advance and retreat rates, and other variables were obtained. To extend the range of data, four additional periods of rapid retreat were examined. Values for the terminus characteristics of water depth, cliff height, and thickness of the terminus, averaged over the width of the glacier and over a year, were then examined in relation to the calculated speeds of calving. A statistical analysis to determine the form and coefficients of an empirical calving relation that approximates the data shows that calving speed is best fitted by a simple proportionality to average water depth at the terminus: 1 where vc is the calving speed and hw the water depth, both averaged over the width and over a year, and c a constant of proportionality. This gives a variance reduction fraction (similar to the coefficient of determination r2) of 0.90.To investigate seasonal changes in calving, data based on shorter time intervals were obtained at the head of embayments from Columbia Glacier. At intervals of approximately two months, the following expression fits intra-yearly calving at Columbia Glacier: 2 where D is the meltwater discharge from the glacier, hj is the height of the ice column unsupported by water buoyancy, a, b, c are constants, and vc and hu are evaluated at the embayment head. D was determined by correlation with a nearby glacial stream, and hu = h _ hw PW/PJ, where h is glacier thickness and pi and pw the densities of ice and water. Best-fit values of b and c are approximately 0.5 and -2, respectively. This yields a variance reduction fraction r2 of 0.83.Equation (2) does not fit data averaged over a year and over the width of the glacier and Equation (1) does not fit data obtained over shorter periods at the head of the embayment. Although the two equations are different in form, for similar or average values of D and h - hw (ice-cliff height), they give approximately similar results over the present range of the geometry of the terminus of Columbia Glacier. Whether this will be true after rapid retreat begins remains to be seen.

Mass Determination by Direct Measurement of Electron Scattering

1975 ◽  
Vol 33 ◽  
pp. 240-241
Author(s):  
M. K. Lamvik ◽  
A. V. Crewe
Keyword(s):  
Cross Section ◽  
Electron Scattering ◽  
Mass Density ◽  
Variable Mass ◽  
Scattering Cross Section ◽  
Mass Determination ◽  
Number Density ◽  
Cross Sectional ◽  
Thin Slice ◽  
Scattering Cross

If a molecule or atom of material has molecular weight A, the number density of such units is given by n=Nρ/A, where N is Avogadro's number and ρ is the mass density of the material. The amount of scattering from each unit can be written by assigning an imaginary cross-sectional area σ to each unit. If the current I0 is incident on a thin slice of material of thickness z and the current I remains unscattered, then the scattering cross-section σ is defined by I=IOnσz. For a specimen that is not thin, the definition must be applied to each imaginary thin slice and the result I/I0 =exp(-nσz) is obtained by integrating over the whole thickness. It is useful to separate the variable mass-thickness w=ρz from the other factors to yield I/I0 =exp(-sw), where s=Nσ/A is the scattering cross-section per unit mass.

A tilting high temperature gas reaction chamber for the JEM 7A T.E.M.

1978 ◽  
Vol 36 (1) ◽  
pp. 70-71
Author(s):  
Brian L. Rhoades
Keyword(s):  
Cross Section ◽  
Reaction Chamber ◽  
Objective Lens ◽  
Reduced Cross Section ◽  
Cross Sectional ◽  
Structural Investigations ◽  
Transmission Electron ◽  
Dynamic Experiments ◽  
Successful Design ◽  
Thermocouple Junction

A gas reaction chamber has been designed and constructed for the JEM 7A transmission electron microscope which is based on a notably successful design by Hashimoto et. al. but which provides specimen tilting facilities of ± 15° aboutany axis in the plane of the specimen.It has been difficult to provide tilting facilities on environmental chambers for 100 kV microscopes owing to the fundamental lack of available space within the objective lens and the scope of structural investigations possible during dynamic experiments has been limited with previous specimen chambers not possessing this facility.A cross sectional diagram of the specimen chamber is shown in figure 1. The specimen is placed on a platinum ribbon which is mounted on a mica ring of the type shown in figure 2. The ribbon is heated by direct current, and a thermocouple junction spot welded to the section of the ribbon of reduced cross section enables temperature measurement at the point where localised heating occurs.

Microstructure of laser-irradiated, conducting Kapton polyimide

1995 ◽  
Vol 53 ◽  
pp. 502-503
Author(s):  
D. L. Callahan ◽  
Z. Ball ◽  
H. M. Phillips ◽  
R. Sauerbrey
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Film Surface ◽  
Cross Sectional ◽  
General Utility ◽  
Transmission Electron ◽  
Considerable Debate ◽  
Potential Applications

Ultraviolet laser-irradiation can be used to induce an insulator-to-conductor phase transition on the surface of Kapton polyimide. Such structures have potential applications as resistors or conductors for VLSI applications as well as general utility electrodes. Although the percolative nature of the phase transformation has been well-established, there has been little definitive work on the mechanism or extent of transformation. In particular, there has been considerable debate about whether or not the transition is primarily photothermal in nature, as we propose, or photochemical. In this study, cross-sectional optical microscopy and transmission electron microscopy are utilized to characterize the nature of microstructural changes associated with the laser-induced pyrolysis of polyimide.Laser-modified polyimide samples initially 12 μm thick were prepared in cross-section by standard ultramicrotomy. Resulting contraction in parallel to the film surface has led to distortions in apparent magnification. The scale bars shown are calibrated for the direction normal to the film surface only.

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