scholarly journals Verification of Time of Concentration Equation for Improved Drainage Design

2019 ◽  
Vol 8 (2) ◽  
pp. 151
Author(s):  
J. C. Osuagwu ◽  
J. C. Agunwamba ◽  
C. E. Nwabunor
Keyword(s):  
Computing Time ◽  
Chloride Concentration ◽  
Cost Effective ◽  
Model Verification ◽  
Time Of Concentration ◽  
Drainage Design ◽  
Measured Time ◽  
Effective Drainage ◽  
Modified Formula ◽  
Concentration Equation

This study focused on verifying the Time of concentration Equation for a more reliable design of drains. Tracer studies were carried out in 1000m long rectangular drains at the University of Nigeria Nsukka. Sodium Chloride which was used as the tracer was introduced at station 1 and samples were collected after 20secs simultaneously at the 9 collection points. Flow parameters including velocity and slope of channel were determined. The collected samples were analyzed in the laboratory for determination of chloride concentration in mg/l. The maximum concentration was 42.11mg/l. Thereafter the time of concentrated was computed by dividing the summation of product of concentration and measured time with the summation of concentration. Through regression analysis, a modified formula for computing time of concentration (tc). Model verification was carried out using experimental data. The results from obtained from the modified Equations were compared respectively with computed results from the commonly used Kirpich formula and measured times of concentration. The results showed no correlation between measured and computed values. There were also marked variations between results from existing and modified formulae. There is therefore need for further verification and validation of the modified Equation. This is necessary in view of the fact that a reliable prediction of time of concentration is key to a cost effective drainage design.

Combining Computer Simulation with Physical Simulation: An Attempt to Validate Turf Runoff Models

1992 ◽  
Vol 6 (3) ◽  
pp. 688-695 ◽  
Author(s):  
James C. Lin ◽  
Robert L. Graney
Keyword(s):  
Model Validation ◽  
Physical Simulation ◽  
Cost Effective ◽  
Model Verification ◽  
Aquatic Environments ◽  
Target Movement ◽  
Surface Transport ◽  
Small Plot ◽  
Selection For ◽  
Runoff Model

Predicting the off-target movement of agrochemicals applied to turf is an essential component for assessing risk to aquatic environments. For surface transport, a fully validated model does not exist. Such a model is required to make cost effective risk assessments and regulatory evaluations. To address this deficiency, a turf model validation program is outlined in this paper. The effect of turf characteristics on the fate and movement of pesticides is presented followed by the discussion of the selection for a proper turf runoff model. The design and implementation of small plot runoff studies and their usefulness in model validation are discussed. The procedures of model calibration and model verification are explained for model validation purpose.

scholarly journals Development of a cost-effective medium for Photorhabdus temperata bioinsecticide production from wastewater and exploration of performance kinetic

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sahar Keskes ◽  
Wafa Jallouli ◽  
Imen Ben Atitallah ◽  
Fatma Driss ◽  
Emna Sahli ◽  
...  
Keyword(s):  
Biomass Production ◽  
Chloride Concentration ◽  
Cost Effective ◽  
Culture Conditions ◽  
Effective Medium ◽  
Inoculum Size ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Optimized Conditions ◽  
Photorhabdus Temperata

AbstractThis study investigates the optimization of the culture conditions for enhancing Photorhabdus temperata biopesticide production using wastewater (WS4) as a raw material. Box-Behnken design (BBD) was used to evaluate the effects of carbon to nitrogen ratio (C/N), sodium chloride concentration and inoculum size on P. temperata biomass production and insecticidal activity. For an enhanced biopesticide production, the optimum operating conditions were as follows: inoculum size = 4%; C/N ratio = 12.5 and [NaCl] = 4 g/L for two responses. 1.95 and 2.75 fold improvements in oral toxicity and biomass production were respectively obtained in the cost-effective medium developed in this study (WS4 I) using the three variables at their optimal values. Under the optimized conditions, WS4 I-grown cells exhibited higher membrane integrity according to flow cytometry analysis since dead cells presented only 9.2% compared to 29.2% in WS4. From batch fermentations carried out in WS4 I and WS4, P. temperata kinetic parameters in terms of biomass production and substrate consumption rates were modeled. The obtained results showed that the maximum specific growth rate in WS4 I was of 0.43 h−1 while that obtained in WS4 was of 0.14 h−1. In addition, the efficiency of P. temperata to metabolize organic carbon was enhanced by optimizing the culture conditions. It reached 72.66% instead of 46.18% in the control fermentation after 10 h of incubation. Under the optimized conditions, P. temperata cells showed the highest specific consumption rate resulting in a toxin synthesis improvement.

scholarly journals Use of Seawater/Brine and Caliche’s Salts as Clean and Environmentally Friendly Sources of Chloride and Nitrate Ions for Chalcopyrite Concentrate Leaching

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 477 ◽  
Author(s):  
Pía Hernández ◽  
Alexis Dorador ◽  
Monserrat Martínez ◽  
Norman Toro ◽  
Jonathan Castillo ◽  
...  
Keyword(s):  
Sulfuric Acid Concentration ◽  
Chloride Concentration ◽  
Cost Effective ◽  
Copper Extraction ◽  
Distilled Water ◽  
Sample Type ◽  
Nitrate Ions ◽  
Cost Effective Alternative ◽  
Chalcopyrite Concentrate ◽  
Pre Treatment

A less harmful approach for the environment regarding chalcopyrite concentrate leaching, using seawater/brine and caliche’s salts as a source of chloride and nitrate ions, was investigated. Different variables were evaluated: sulfuric acid concentration, sodium nitrate concentration, chloride concentration, source of water (distilled water, seawater, and brine), temperature, concentrate sample type, nitrate source (analytical grade and industrial salt), and pre-treatment methods in order to obtain maximum copper extraction. All tests were performed at moderate temperatures (≤45 °C) and atmospheric pressure. The leaching system using distilled water, seawater, and brine base media resulted in copper extraction of 70.9%, 90.6%, and 86.6% respectively. The leaching media, with a concentration of 20 g/L Cl−, obtained a maximum Cu extraction of 93.5%. An increase in the concentration of H2SO4 and NaNO3 from 0.5 to 0.7 M, led to an increase in the copper extraction. The use of an industrial salt compared to the analytical salt did not show great variations in the percentage of extraction achieved, which would be a good and cost effective alternative. The increase in temperature from 25 to 45 °C showed a great effect on the copper leaching (of 60% until 90.6%, respectively). The pre-treatment is suggested to increase copper extraction from 60.0% to 71.4%.

scholarly journals Development of a Cost-effective Medium for Photorhabdus Temperata Bioinsecticide Production From Wastewater and Exploration of Performance Kinetic

2020 ◽  
Author(s):  
Sahar Keskes ◽  
Wafa Jallouli ◽  
Imen Ben Atitallah ◽  
Mohamed Chamkha ◽  
Slim Tounsi
Keyword(s):  
Biomass Production ◽  
Chloride Concentration ◽  
Cost Effective ◽  
Culture Conditions ◽  
Effective Medium ◽  
Inoculum Size ◽  
Raw Material ◽  
Oral Toxicity ◽  
Operation Conditions ◽  
Photorhabdus Temperata

Abstract This study investigates the optimization of culture conditions for enhancing Photorhabdus temperata biopesticide production using wastewater (WS4) as a raw material. Box-Behnken design (BBD) was used to evaluate the effect of carbon to nitrogen ratio (C/N), NaCl concentration and inoculum size on Photorhabdus temperata biomass production and insecticidal activity. Modelling results suggest that the selected variables had contributed significantly to the responses. For enhanced biopesticide production the optimum operation conditions were as follow: inoculum size=4 %; C/N ratio=12.5 and sodium chloride concentration= 4 g/L for two responses. 1.95 and 2.75 folds improvement in oral toxicity and biomass production, respectively, were obtained when using the three variables at their optimum values. From batch fermentations carried out in the cost-effective medium developed in this study (WS4 I) and WS4 used as control, P. temperata kinetic parameters in term of biomass production and substrate consumption were modeled. The obtained results showed that the maximum specific growth rate was of 0.38 h-1 compared to 0.16 h-1 obtained in WS4. In addition, the efficiency of P. temperata to metabolize organic carbon was enhanced by optimizing culture conditions reaching 70 % instead of 47.2 % in the control fermentation. Under the optimized conditions, P. temperata cells showed higher specific consumption rate resulting in P. temperata toxin synthesis improvement.

scholarly journals A Simple Method to Develop a Formula for Estimating Concentration Time of Drainage Design

2020 ◽  
Vol 8 (3) ◽  
pp. 137-142
Author(s):  
Alfiansyah Yulianur ◽  
Sugianto Sugianto ◽  
Frystia Mala Puspita
Keyword(s):  
Catchment Area ◽  
Rainfall Intensity ◽  
Peak Flow ◽  
Measurement Data ◽  
Zoysia Japonica ◽  
Simple Method ◽  
Time Of Concentration ◽  
Estimation Formula ◽  
Concentration Time ◽  
Drainage Design

Concentration time of rainfall is an important aspect to determine drainage design. A general rational formula is used to determine design flood or peak flow in urban drainage planning, especially for storm sewer design. The use of this balanced formula requires rainfall intensity, whose duration of rain is equal or more than the time of concentration. This time of concentration is determined using an estimation formula whose formation requires measurement data of the time of concentration. This study introduces how to measure the time of concentration using the concept of-rational-hydrograph, in which peak flow occurs at the time of concentration. To fulfill the aim of this research, an experimental of catchment area planted with Zoysia Japonica grass and showered with a rainfall simulator was conducted. The length of the flow path on the land, L, given in 5 variations, namely 50 cm, 100 cm, 150 cm, 200 cm, and 250 cm, was used. The slope of the land, S, is given in 3 variations, namely 2.8 %, 5,6%, and 8.8%. For each variation of L and S, the experimental catchment area was poured with a fixed rainfall intensity, which is 60 mm/hour. The flow was measured every 5 minutes intervals. Then, from the relationship of flow and time, a rational hydrograph was formed, from which the time of concentration, Tc, was deduced. This Tc value was treated as the measured Tc to form the Tc estimation formula using the regression formula. The formula is Tc = 3.543 + 1.211 L – 17.119 S, with the coefficient of determination R2 = 0.98. These results show that the determination of Tc using the concept of the rational- hydrograph is acceptable. This formula applies to L and S values greater than zero and applies to land covered by Zoysia Japonica grass. Further research is needed for other types of land cover to validate the formula obtained in this research.

scholarly journals Ferric chloride for odour control: studies from wastewater treatment plants in India

2020 ◽  
Author(s):  
T. C. Prathna ◽  
Ankit Srivastava
Keyword(s):  
Wastewater Treatment ◽  
Ferric Chloride ◽  
Hydrogen Sulphide ◽  
Wastewater Treatment Plants ◽  
Chloride Concentration ◽  
Oxygen Demand ◽  
Cost Effective ◽  
Odour Control ◽  
Pre Treatment ◽  
Wastewater Samples

Abstract This study was about the feasibility of using ferric chloride as an agent for odour control in wastewater treatment plants (WWTPs) due to hydrogen sulphide emission. Total inlet sulphide concentrations at 11 WWTPs in Delhi were measured and ranged between 1.1 and 14.8 mg/L. Wastewater samples from Najafgarh drain were used in jar tests to estimate the ferric chloride concentration required to obtain acceptable treatment. Ferric chloride was effective in removing sulphide, phosphate and total suspended solids (TSS), and gave significant biological oxygen demand (BOD) reduction. It was ineffective, however, in removing ammoniacal-nitrogen. A dose of 40 mg/L removed 76% of total sulphide, which corresponds to a significant reduction in hydrogen sulphide emission. The study demonstrated that ferric chloride can be used as a cost-effective pre-treatment step in WWTPs to reduce sulphur-related odours significantly, as well as TSS, BOD and phosphate from wastewater.

CORROSION INITIATION TIME OF REINFORCED CONCRETE STRUCTURES IN MARINE ENVIRONMENT — A PROBABILISTIC APPROACH

2008 ◽  
Vol 15 (02) ◽  
pp. 93-99
Author(s):  
A. SRIVIDYA ◽  
SATISH B. ALLAMPALLEWAR
Keyword(s):  
Probabilistic Approach ◽  
Chloride Concentration ◽  
Cost Effective ◽  
Threshold Value ◽  
Steel Reinforcement ◽  
Initiation Time ◽  
Expected Time ◽  
Corrosion Initiation ◽  
Cost Effective Approach ◽  
Corrosion Initiation Time

An approximate explicit method from literature to estimate the corrosion initiation time of steel reinforcement in concrete is developed to incorporate random variables which affect the diffusion rate. The method accounts for uncertainties of input parameters and predicate expected time of first corrosion for the chosen risk of corrosion and its variance. Method is also utilized to rank the sensitive parameters to initiate steel reinforcement corrosion. Corrosion is initiated when the chloride concentration on steel reinforcement exceeds a threshold value. Corrosion initiation time is useful for owner, designer, or to an organization to take decision in time of priority of repairs, repair strategy, corrosion protection in order to optimize maintenance planning and budgeting. Planned maintenance at the optimum time is the safest and most cost effective approach.

Seven-Sensor Fast-Response Probe for Full-Scale Wind Turbine Flowfield Measurements

2011 ◽  
Vol 133 (8) ◽  
Author(s):  
M. Mansour ◽  
G. Kocer ◽  
C. Lenherr ◽  
N. Chokani ◽  
R. S. Abhari
Keyword(s):  
Wind Turbine ◽  
Wind Profile ◽  
Lift Coefficient ◽  
Cost Effective ◽  
Fast Response ◽  
Full Scale ◽  
Site Assessment ◽  
Measured Time ◽  
Wind Profiles ◽  
Logarithmic Height

The unsteady wind profile in the atmospheric boundary layer upstream of a modern wind turbine is measured. The measurements are accomplished using a novel measurement approach that is comprised of an autonomous uninhabited aerial vehicle (UAV) that is equipped with a seven-sensor fast-response aerodynamic probe (F7S-UAV). The autonomous UAV enables high spatial resolution (∼6.3% of rotor diameter) measurements, which hitherto have not been accomplished around full-scale wind turbines. The F7S-UAV probe developed at ETH Zurich is the key-enabling technology for the measurements. The time-averaged wind profile from the F7S-UAV probe is found to be in very good agreement to an independently measured profile using the UAV. This time-averaged profile, which is measured in moderately complex terrain, differs by as much as 30% from the wind profile that is extrapolated from a logarithmic height formula; therefore, the limited utility of extrapolated profiles, which are commonly used in site assessments, is made evident. The time-varying wind profiles show that at a given height, the velocity fluctuations can be as much as 44% of the time-averaged velocity, therefore indicating that there are substantial loads that may impact the fatigue life of the wind turbine’s components. Furthermore, the shear in the velocity profile also subjects the fixed pitch blade to varying incidences and loading. Analysis of the associated velocity triangles indicates that the sectional lift coefficient at midspan of this modern turbine would vary by 12% in the measured time-averaged wind profile. These variations must be accounted in the structural design of the blades. Thus, the measurements of the unsteady wind profile accomplished with this novel measurement system demonstrate that it is a cost effective complement to the suite of available site assessment measurement tools.

scholarly journals Comparative Analysis of Some Existing Models for Estimating the Time of Concentration for Watersheds in Anambra State, Nigeria

2021 ◽  
pp. 64-75
Author(s):  
J. C. Agunwamba ◽  
N. C. Mmonwuba
Keyword(s):  
Comparative Analysis ◽  
Local Government ◽  
Correlation Coefficient ◽  
Robust Design ◽  
Correlation Measure ◽  
Anambra State ◽  
Time Of Concentration ◽  
Measured Time ◽  
Estimation Of Time ◽  
Area Data

This study considered the estimation of the time of concentration (TC) using 30 different watersheds in Anambra State, Nigeria. The study assessed the performance of some existing models for the estimation of time of concentration in the study area. Data for this research were collected from watersheds located at Awka-South Local Government in Anambra State. A measured time of concentration values was also obtained by using a tracer at the watershed divide and the time it took the tracer to get the outlet of the watershed was recorded. This was carried out on all the 30 watersheds at the same time. The length, slope and area of the 30 watersheds were also measured. Thereafter, the time of concentration was estimated using the 30 existing models. The extent of linear association between the observed and estimated time of concentration for the different models was determined. The outcome of the study revealed that the Ventura model (Tc12) developed in Italy recorded the highest correlation coefficient with a measure of 0.681, followed by DNOS model (Tc14) with a coefficient measure of 0.661 while the least performing model was Picking model (Tc13) with -0.423 correlation measure. There was also an obvious difference in the values of the time of concentration calculated using the different models. Therefore there is always a need to verify any model to be used for estimating the time of concentration in other to have a more robust design. 

In situ measurements of target strength with optical and model verification: a case study for blue grenadier, Macruronus novaezelandiae

2011 ◽  
Vol 68 (9) ◽  
pp. 1986-1995 ◽  
Author(s):  
Rudy J. Kloser ◽  
Tim E. Ryan ◽  
Gavin J. Macaulay ◽  
Mark E. Lewis
Keyword(s):  
Cost Effective ◽  
In Situ Measurements ◽  
Model Verification ◽  
Optical Measurements ◽  
Target Strength ◽  
Fish Length ◽  
Neutral Buoyancy ◽  
Cost Effective Method

Abstract Kloser, R. J., Ryan, T. E., Macaulay, G. J., and Lewis, M. E. 2011. In situ measurements of target strength with optical and model verification: a case study for blue grenadier, Macruronus novaezelandiae. – ICES Journal of Marine Science, 68: 1986–1995. In situ measurements of target strength (TS) of isolated fish surrounding dense schools need to be representative of the schooling fish to calculate their echo-integrated biomass. Using synchronous optical and acoustic measurements from a pelagic fishing net, the standard length (81 cm, n = 128), tilt-angle (−9°), and net-disturbed in situ TS (−34.4 dB) of Australian Macruronus novaezelandiae (blue grenadier) were confirmed at depth. In situ drift experiments of assumed undisturbed but dispersed blue grenadier recorded a mean TS of −31.8 dB (CI −33.1 to −30.9 dB) with attributed fish standard lengths of 83 cm (s.d. 7.5 cm) and weight 2.5 kg. Modelling the gasbladder showed that uncertainties in fish length, orientation, and gasbladder size could explain the differences observed. Blue grenadiers have negative buoyancy because the cavity size of their gasbladder is smaller than the volume of gas required for neutral buoyancy at depth. For the same species and length, New Zealand hoki weigh less and have smaller gasbladders than Australian blue grenadier, suggesting a conversion factor of 1.10 in length for comparative measurements. Net-attached acoustic and optical measurements indicate that model and drift in situ measurements are biased high by 2.9 and 1.0 dB, respectively. Net-attached acoustic and optical measurements are a cost-effective method of monitoring TS routinely at depth for changes in species length and weight.

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