Design of rainwater detention basins

2020 ◽  
Author(s):  
Dan Rosbjerg
Keyword(s):  
Return Period ◽  
Current Practice ◽  
Design Method ◽  
Volume Curve ◽  
Outflow Rate ◽  
Detention Basins ◽  
Intensity Duration Frequency ◽  
The One ◽  
Linear Reservoir ◽  
Current Guidelines

<p>Traditionally in Denmark, rainwater detention basins are designed based on an input box rain with a given return period and a constant outflow from the basin. The water authorities specify the outflow rate in order to avoid erosion in the recipient. Intensity-Duration-Frequency (IDF) curves are used as a prerequisite for the method. Given the design return period, and varying the duration of the box rain, the basin volume that prevents spill from the basin can be determined. By analysing for a series of outflow rates, a basin volume curve for the selected return period can be developed. The current practice is revisited, and a new analytical solution for the duration of the design rain is found.</p><p>A constant outflow rate for the basin is, however, not always a realistic assumption, and thus there is a risk for underestimation. An alternative design method has been analysed, assuming that the outflow from the basin takes place corresponding to at linear reservoir with maximum outflow rate equal to the one specified by the water authorities. The method is described in detail, and the results compared with those of the current guidelines.</p>

scholarly journals The effect of sorbitol and white sweet potatoes (Ipomea batatas L.) inulin extract application on marshmallow physical, chemical and organoleptic properties

Food Research ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 298-305
Author(s):  
B. Yudhistira ◽  
A.K. Putri ◽  
S. Prabawa
Keyword(s):  
Sweet Potato ◽  
Design Method ◽  
Sweet Potatoes ◽  
Physical Chemical ◽  
Organoleptic Characteristics ◽  
Randomized Design ◽  
Ipomea Batatas ◽  
The Difference ◽  
The One ◽  
High Calorie

Marshmallow belongs to a high-calorie food that requires a low-calorie substitute for sucrose, one of which is sorbitol. Marshmallow has the potential to become a functional food with the addition of inulin contained within white sweet potatoes. Inulin refers to a type of fructan carbohydrate which contains fiber and has the potential as a prebiotic that is beneficial for the human’s body. This study aims to determine the effect of the addition of white sweet potato (Ipomea batatas L.) inulin extract and sorbitol on the physical, chemical and organoleptic characteristic of marshmallows and to obtain the best marshmallow’s formula through white sweet potato (Ipomea batatas L.) inulin extract and sorbitol addition. The completely randomized design method (CRD) applied in this study consisted of one factor, namely the difference in formulation between the concentration of white sweet potato inulin extract (2% and 3%) and the concentration of sorbitol (25%, 50%, and 75%). The statistical analysis utilized the One Way Analysis of Variance (ANOVA) method using SPSS. The results of this study indicated that the addition of white sweet potato inulin extract and sorbitol had a significant effect on tensile strength, density, moisture content, ash content, total calories, dietary fiber, and organoleptic characteristics of marshmallows. The best formula for marshmallows was formula 4 with the addition of 2% white sweet potato inulin extract and 50% sorbitol.

scholarly journals Design Values for Precipitation and Floods from M5 Values

2000 ◽  
Vol 31 (4-5) ◽  
pp. 357-372 ◽  
Author(s):  
Jonas Elíasson
Keyword(s):  
Natural Resource ◽  
Return Period ◽  
Coefficient Of Variation ◽  
Statistical Distribution ◽  
Engineering Research ◽  
Design Values ◽  
Intensity Duration Frequency ◽  
Two Parameters ◽  
The University ◽  
Frequency Curves

The M5 method, originally proposed by the Natural Resource Council in UK, is used for estimating precipitation in Iceland. In this method the M5 (24-hour precipitation with 5-year return period) is used as an index variable. Instead of the usual approach in estimating regional values of the coefficient of variation another coefficient, Ci is used. The M5 and the Ci define together a generalised distribution that can be utilised to estimate the statistical distribution of precipitation anywhere in the country. M5 maps have been prepared for this purpose by the Engineering Research Institute of the University of Iceland. Methods have been devised to derive PMP values from the M5 values. This paper describes the method and gives examples of calculation. It is also shown that the same CDF applies for the observations of shorter duration precipitation available in Iceland. By applying the principle of identical statistical distribution for standardised annual maxima of any duration, IDF (Intensity – Duration – Frequency) curves have been derived. This allows the IDF – values to be calculated on basis of M5 and Ci, which are the two-parameters that define the generalised precipitation distribution.

scholarly journals Establishment of IDF-curves for precipitation in the tropical area of Central Africa - comparison of techniques and results

2004 ◽  
Vol 4 (3) ◽  
pp. 375-387 ◽  
Author(s):  
B. Mohymont ◽  
G. R. Demarée ◽  
D. N. Faka
Keyword(s):  
Return Period ◽  
Central Africa ◽  
Tropical Region ◽  
Data Sets ◽  
Physically Based ◽  
Physically Based Models ◽  
Comparison Of Techniques ◽  
Idf Curves ◽  
Intensity Duration Frequency ◽  
Technique Comparison

Abstract. The establishment of Intensity-Duration-Frequency (IDF) curves for precipitation remains a powerful tool in the risk analysis of natural hazards. Indeed the IDF-curves allow for the estimation of the return period of an observed rainfall event or conversely of the rainfall amount corresponding to a given return period for different aggregation times. There is a high need for IDF-curves in the tropical region of Central Africa but unfortunately the adequate long-term data sets are frequently not available. The present paper assesses IDF-curves for precipitation for three stations in Central Africa. More physically based models for the IDF-curves are proposed. The methodology used here has been advanced by Koutsoyiannis et al. (1998) and an inter-station and inter-technique comparison is being carried out. The IDF-curves for tropical Central Africa are an interesting tool to be used in sewer system design to combat the frequently occurring inundations in semi-urbanized and urbanized areas of the Kinshasa megapolis.

Estimate of Storm Induced Beach Erosion Through the ETS Approach

2008 ◽  
Author(s):  
Rosaria E. Musumeci ◽  
Carla Faraci ◽  
Felice Arena ◽  
Enrico Foti
Keyword(s):  
Return Period ◽  
Extreme Events ◽  
Coastal Erosion ◽  
Beach Erosion ◽  
Coastal Protection ◽  
Shoreline Retreat ◽  
Submerged Breakwater ◽  
The One

In the present paper the risk of beach erosion is evaluated by applying the Equivalent Triangular Storm (ETS). The selected case study is ‘La Plaja’ beach located in the South of Catania, Sicily. The proposed approach has shown that when the ETS model is applied, a shoreline retreat has been found which on average overestimates the one obtained by means of actual storm data of about 35%. The model has been applied for the determination of the return period of shoreline recession due to beach erosion during extreme events in order to recover risk maps, which can provide useful information in the planning of coastal interventions. Finally the model has been applied to predict the shoreline retreat in the presence of a submerged breakwater, confirming that the introduction of such coastal protection work strongly limits the risk of coastal erosion.

On the Design of a Long-Stroke Beam-Based Compliant Mechanism Providing Quasi-Constant Force

2019 ◽  
Author(s):  
Pietro Bilancia ◽  
Alessandro Geraci ◽  
Giovanni Berselli
Keyword(s):  
Compliant Mechanism ◽  
Design Method ◽  
Reaction Force ◽  
Constant Force ◽  
Physical Prototype ◽  
Flexible Behavior ◽  
Improved Design ◽  
The One ◽  
Long Stroke ◽  
Integrated Software

Abstract In this paper the design of a linear long-stroke quasi-constant force compliant mechanism (CM) is presented and discussed. Starting from a flexure-based slider-crank mechanism, providing the required constant force within a rather limited deflection range, the paper reports about the shape optimization carried out with the specific aim of extending the available CM operative range. The proposed device is suitable in several precision manipulation systems, which require to maintain a constant-force at their contact interface with the manipulated object. Force regulation is generally achieved by means of complex control algorithms and related sensory apparatus, resulting in a flexible behavior but also in high costs. A valid alternative may be the use of a purposely designed CM, namely a purely mechanical system whose shape and dimensions are optimized so as to provide a force-deflection behavior characterized by zero stiffness. In the first design step, the Pseudo-Rigid Body (PRB) method is exploited to synthesize the sub-optimal compliant configuration, i.e. the one characterized by lumped compliance. Secondly, an improved design alternative is evaluated resorting to an integrated software framework, comprising Matlab and ANSYS APDL, and capable of performing non-linear structural optimizations. The new embodiment makes use of a variable thickness beam, whose shape and dimensions have been optimized so as to provide a constant reaction force in an extended range. Finally, a physical prototype of the beam-based configuration is produced and tested, experimentally validating the proposed design method.

Kingdom Sayings and Parables of Jesus in the Apocryphon of James: Tradition and Redaction

1983 ◽  
Vol 29 (1) ◽  
pp. 1-24 ◽  
Author(s):  
Charles W. Hedrick
Keyword(s):  
New Testament ◽  
Recent Article ◽  
Current Practice ◽  
Early Stage ◽  
The Other ◽  
Nag Hammadi ◽  
Apocryphal Gospels ◽  
The New Testament ◽  
One Step ◽  
The One

In a recent article Helmut Koester argues against the current practice of distinguishing between canonical Gospels, on the one hand, and apocryphal gospels, on the other, and treating the apocryphal gospels as ‘step children’ of New Testament research. Koester maintains that there are a number of the ‘apocryphal’ gospels which ‘belong to a very early stage in the development of gospel literature — a stage that is comparable to the sources which were used by the gospels of the New Testament.’ One of those texts to which he points is the Nag Hammadi tractate the Apocryphon of James. This paper is an attempt to legitimize one ‘step child’ of New Testament scholarship as a valid source for investigating the earliest levels of the Jesus traditions.

scholarly journals Modelling and assessment of urban flood hazards based on rainfall intensity-duration-frequency curves reformation

2016 ◽  
Author(s):  
Reza Ghazavi ◽  
Ali Moafi Rabori ◽  
Mohsen Ahadnejad Reveshty
Keyword(s):  
Return Period ◽  
Urban Areas ◽  
Rainfall Intensity ◽  
Flood Hazards ◽  
Return Periods ◽  
Urban Flood ◽  
Design Storm ◽  
Hourly Rainfall ◽  
Idf Curves ◽  
Intensity Duration Frequency

Abstract. Estimate design storm based on rainfall intensity–duration–frequency (IDF) curves is an important parameter for hydrologic planning of urban areas. The main aim of this study was to estimate rainfall intensities of Zanjan city watershed based on overall relationship of rainfall IDF curves and appropriate model of hourly rainfall estimation (Sherman method, Ghahreman and Abkhezr method). Hydrologic and hydraulic impacts of rainfall IDF curves change in flood properties was evaluated via Stormwater Management Model (SWMM). The accuracy of model simulations was confirmed based on the results of calibration. Design hyetographs in different return periods show that estimated rainfall depth via Sherman method are greater than other method except for 2-year return period. According to Ghahreman and Abkhezr method, decrease of runoff peak was 30, 39, 41 and 42 percent for 5-10-20 and 50-year return periods respectively, while runoff peak for 2-year return period was increased by 20 percent.

A New Approach to The Design of Fan Volute Profiles

1996 ◽  
Vol 210 (3) ◽  
pp. 287-294 ◽  
Author(s):  
D T Qi ◽  
M J Pomfret ◽  
K Lam
Keyword(s):  
Design Method ◽  
Operating Conditions ◽  
Flow Angle ◽  
New Approach ◽  
One Dimensional ◽  
Distribution Form ◽  
Flow Parameters ◽  
Centrifugal Fans ◽  
Ultimate Objective ◽  
The One

In traditional volute design methods, the flow at the volute inlet is assumed to be uniform according to one-dimensional theory. However, many experimental results have shown that under the design operating conditions, the actual distributions of the flow parameters at the volute inlet are different from those predicted by the ideal assumption. This is because of the influence of the non-axisymmetrical volute geometry, especially due to the presence of the volute tongue. Based on this fact, a new method was considered whereby different volute profiles can be generated by varying the distributions of flow parameters at the volute inlet. The ultimate objective is to achieve the optimal volute profile design so that the performance of a centrifugal machine can be improved. In this paper, a two-dimensional inverse method has been used to redesign the original volute profiles of two centrifugal fans. The results show that the method presented provides effective improvement to the one-dimensional volute design method. The controlled distribution form of volute inlet flow angle α4 in the redesign is qualitatively discussed and can be used for reference in the volute design and further research.

An Axiomatic Approach to Design for Sustainable End-of-Life: A Review of Literature

2013 ◽  
Vol 315 ◽  
pp. 705-709 ◽  
Author(s):  
Lee Guang Beng ◽  
Badrul Omar
Keyword(s):  
Product Design ◽  
End Of Life ◽  
Design Method ◽  
Axiomatic Design ◽  
Axiomatic Approach ◽  
Development Stage ◽  
Design Stage ◽  
Life Cycle Stages ◽  
Sustainable Product Development ◽  
The One

This paper aims to provide an insight to later researchers on the application of axiomatic design in the area of design for end-of-life (EOL) management. Among all life cycle stages of a product, design and development stage is the one that influences the later stages the most in terms of environmental impacts. In order to achieve sustainable product development, one of the considerations to be taken during the design stage is EOL management. EOL management process can be enhanced by utilizing a robust design method as well as an effective method for evaluating product design. Recent researches show that application of axiomatic design in the field of eco-design (especially design for EOL management) is still in a premature stage despite having a vast application area that covers the aspect of product design, manufacturing and supply chain management. Nonetheless, a case study published recently on eco-design using axiomatic approach has shown adequate feasibility and effectiveness. Therefore, design for sustainable EOL using axiomatic approach is worth further exploration.

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