Multi-criteria Decision Support System for Siemianowka Reservoir under Uncertainties

Protection of biodiversity against climatic variations became recently one of the most important issues in water management politics. In the case of a river system it is necessary to provide desirable water conditions for protected ecosystems. This paper presents an application of a Multiple Criteria Decision Suppport System for optimal management of a reservoir located in NE Poland in the Upper Narew Basin. The proposed system allows tradeoff between different reservoir users, including protected wetland ecosystems of the Narew Nation Park to be found. The most challenging task was to take the account of inherent uncertainties related to the model structure. It was done using stochastic formulation of the reservoir control problem. Optimisation was carried out for several criteria:wetland water requirements, agricultural, energy production, flood protection, fishery and reservoir storage. The goal was to achieve a desirable water management regime within the defined safety levels. These highly nonliniear constrains were met through the minimisation of convex functions by solving a linear programming problem within Multiple Criteria Analysis

Modeling nutrient removal and energy consumption in an advanced activated sludge system under uncertainty

Activated sludge models are widely used to simulate, optimize and control performance of wastewater treatment plants (WWTP). For simulation of nutrient removal and energy consumption, kinetic parameters would need to be estimated, which requires an extensive measurement campaign. In this study, a novel methodology is proposed for modeling the performance and energy consumption of a biological nutrient removal activated sludge system under sensitivity and uncertainty. The actual data from the wastewater treatment plant in Slupsk (northern Poland) were used for the analysis. Global sensitivity analysis methods accounting for interactions between kinetic parameters were compared with the local sensitivity approach. An extensive procedure for estimation of kinetic parameters allowed to reduce the computational effort in the uncertainty analysis and improve the reliability of the computational results. Due to high costs of measurement campaigns for model calibration, a modification of the Generalized Likelihood Uncertainty method was applied considering the location of measurement points. The inclusion of nutrient measurements in the aerobic compartment in the uncertainty analysis resulted in percentages of ammonium, nitrate, ortho-phosphate measurements of 81%, 90%, 78%, respectively, in the 95% confidence interval. The additional inclusion of measurements in the anaerobic compartment resulted in an increase in the percentage of ortho-phosphate measurements in the aerobic compartment by 5% in the confidence interval. The developed procedure reduces computational and measurement efforts, while maintaining a high compatibility of the observed data and model predictions. This enables to implement activated sludge models also for the facilities with a limited availability of data

An advanced tool integrating failure and sensitivity analysis into novel modeling of the stormwater flood volume

An innovative tool for modeling the specific flood volume was presented that can be applied to assess the need for stormwater network modernization as well as for advanced flood risk assessment. Field measurements for a catchment area in Kielce, Poland, were used to apply the model and demonstrate its usefulness. This model extends the capability of recently developed statistical and machine learning hydrodynamic models developed from multiple runs of the US Environmental Protection Agency (EPA) Storm Water Management Model (SWMM). The extensions enable the inclusion of (1) the characteristics of the catchment and its stormwater network, calibrated model parameters expressing catchment retention, and the capacity of the sewer system; (2) extended sensitivity analysis; and (3) risk analysis. Sensitivity coefficients of calibrated model parameters include correction coefficients for percentage area, flow path, depth of storage, and impervious area; Manning roughness coefficients for impervious areas; and Manning roughness coefficients for sewer channels. Sensitivity coefficients were determined with respect to rainfall intensity and characteristics of the catchment and stormwater network. Extended sensitivity analysis enabled an evaluation of the variability in the specific flood volume and sensitivity coefficients within a catchment, in order to identify the most vulnerable areas threatened by flooding. Thus, the model can be used to identify areas particularly susceptible to stormwater network failure and the sections of the network where corrective action should be taken to reduce the probability of system failure. The simulator developed to determine the specific flood volume represents an alternative approach to the SWMM that, unlike current approaches, can be calibrated with limited topological data availability; therefore, the aforementioned simulator incurs a lower cost due to the lower number and lower specificity of data required.</p

Guidance on how to identify impacts of hydromorphological degradation on riparian ecosystems. Deliverable 3.4 of REFORM (REstoring rivers FOR effective catchment Management), a collaborative project (large-scale integrating project) funded by the European Commission within the 7th Framework Grant Agreement 282656

The aim of this deliverable is to address the impact of hydromorphological degradation on floodplain and riparian ecosystems, with specific focus on vegetation, fish and invertebrate responses and to provide guidance on how to identify those impacts

Multiple-criteria decision support system for Siemianowka Reservoir under uncertainties

This paper presents a Multiple Criteria Decision Support System for the optimal management of the Siemianowka reservoir. The reservoir is localized on the Narew River upstream the NNP. The river system under consideration consists of a storage reservoir and a 100 km long River Narew reach, at which end the NNP is located. The goal of the work is to provide decision makers with a tool that would allow the safety of the NNP environmental requirements within the reservoir management policy to be included. An important issue is the competition between many water-dependent systems and agents, e.g., agriculture, energy, wetlands, for limited water resources. The proposed system allows a trade-off between different reservoir users to be found, including protected wetland ecosystems of the Narew Nation Park. Unobserved inflows play an essential role in the river water balance and are dealt with use of k-NN technique. In addition, as the optimization problem requires numerous realizations of the river model, a numerically efficient Stochastic Linear Transfer Function was applied to flow routing

Heat effects measurements in process of dynamic crash of polymer composites

In the work, the attempt to determine the influence of loading rate on temperature of the surface of the crushed composite energy absorbing elements was undertaken. The specimens made of epoxy composites reinforced with glass fabrics and carbon fabrics of the structures [(0/90)T ]n were subjected to dynamic investigations. Thermovision investigations were conducted during energy absorbing tests. A thermovision camera enables the measurement of the temperature on the whole surface of the specimen visible in the camera lens while the measurement with the use of thermocouple is only local and has great heat inertia. During the investigations, the increase of specimen temperature related to impact velocity occurs. The temperature increase is caused by friction between the particles of the crushed specimen and by friction between the specimen and the support of the strength machine. At high loading rates, the increase of temperature on the surface of the specimens was significantly greater than the softening temperature of the epoxy resin E-53

Doświadczalna i numeryczna analiza niezatopionego wypływu spod zasuwy

The problem of sluice gate flow is analyzed using two models: a simplified one, derived according to the concept of the Potential Field (PF), and a more complex form, based on the Reynolds Average Navier-Stokes (RANS) equations. The numerical solution is compared with experimental data, including measurements performed by authors and results acquired from literature. Despite its simplicity, the PF model provides a satisfactory agreement with the measurements. The slightly worse performance of the RANS model comes from an overestimation of energy losses.Niezatopiony wypływ wody spod zasuwy opisano dwoma modelami: uproszczonym, wyprowadzonym na podstawie teorii płaskiego przepływu potencjalnego (PF), i modelem o większym stopniu złożoności, bazującym na uśrednieniu Reynoldsa równań Naviera-Stokesa (RANS). Wyniki obliczeń przepustowości scharakteryzowano współczynnikami wydatku i porównano z wynikami własnych pomiarów hydraulicznych oraz podawanymi w literaturze. Współczynniki wydatku uzyskane z modelu PF są zbliżone do wyników badań eksperymentalnych. Nieco większe różnice wartości współczynników wydatku uzyskano z obliczeń modelem RANS. Wynika to z przeszacowania strat energii strumienia wody

Investigations of composite energy absorbing elements

In this work the problem connected with an improvement of the road safety through implementation of additional elements absorbing the hitting energy is taken into consideration. The experimental results of a basic absorbing element of the glass epoxy composite are presented. The results of these tests will serve for the construction of a reliable numerical model of a panel of protective elements. The coincidence between the experimental and numerical results is also proved, showing that introduced approach to the modelling of the process of the progressive destruction and the energy absorption by composite elements is not only properly assumed but is very promising for the future. Efforts, which lead to increase the amount of absorbed energy need actions, directed to improving absorbing energy properties of used elements. Therefore, the received results will serve as guidelines for elaboration the methodology of the research structures of that type and also could be used in further research works within the scope of increasing the road security. In the article it is also proved that there is the necessity to conduct the series of comparative experiments and also tests verifying numerical studies at loading speeds, which can be compared with ones in reality, e.g. crash test or shock wave of an explosion. The validated, in such way, method of numerical simulations enables the limitation of costly and long-lasting research of real objects

Influence of hardness on mechanical properties of elastomers

In this paper, elastomers with different hardness factors were examined to evaluate the influence of the hardness on their mechanical properties. The following hardness numbers, measured in Shore A hardness scale, were investigated: 40; 60; 70 and 90°. Basic mechanical tests i.e. axial tension and axial compression have been performed in order to calculate elastic properties and stress values corresponding to the fixed strains: epsilon = 0.2; 0.3 and 0.5. The sigma (epsilon) dependences from the tension and compression tests are nonlinear and have different shapes. The tension plot can be described by a convex parabola, while the compression curve can be approximated by a concave one. dynamic load tests with loading freąuencies 0.01; 0.1; 1.0 and 3,OHz were performed in order to determine the hysteresis loop and to obtain force and displacement dependences in time. From those results the following factors were calculated: relative damping coefficient and mechanical loss angle, as well as their dependence on load frequencies. The influence of hardness on both in-phase and out-of-phase components of normal modulus were investigated. The sensitivity of the examined elastomers to the loading rate was also investigated