On the possibility of calibrating urban storm-water drainage models using gauge-based adjusted radar rainfall estimates

Traditionally, urban storm water drainage models have been calibrated using only raingauge data, which may result in overly conservative models due to the lack of spatial description of rainfall. With the advent of weather radars, radar rainfall estimates with higher temporal and spatial resolution have become increasingly available and have started to be used operationally for urban storm water model calibration and real time operation. Nonetheless, the insufficient accuracy of radar rainfall estimates has proven problematic and has hindered its widespread practical use. This work explores the possibility of improving the applicability of radar rainfall estimates to the calibration of urban storm-water drainage models by employing gauge-based radar rainfall adjustment techniques. Four different types of rainfall estimates were used as input to the recently verified urban storm water drainage models of the Beddington catchment in South London; these included: raingauge, block-kriged raingauge, radar (UK Met Office Nimrod) and the adjusted (or merged) radar rainfall estimates. The performance of the simulated flow and water depths was assessed using measurements from 78 gauges. Results suggest that a better calibration could be achieved by using the block-kriged raingauge and the adjusted radar estimates as input, as compared to using only radar or raingauge estimates

Improving rainfall nowcasting and urban runoff forecasting through dynamic radar-raingauge rainfall adjustment

The insufficient accuracy of radar rainfall estimates is a major source of uncertainty in short-term quantitative precipitation forecasts (QPFs) and associated urban flood forecasts. This study looks at the possibility of improving QPFs and urban runoff forecasts through the dynamic adjustment of radar rainfall estimates based on raingauge measurements. Two commonly used techniques (Kriging with External Drift (KED) and mean field bias correction) were used to adjust radar rainfall estimates for a large area of the UK (250,000 km2) based on raingauge data. QPFs were produced using original radar and adjusted rainfall estimates as input to a nowcasting algorithm. Runoff forecasts were generated by feeding the different QPFs into the storm water drainage model of an urban catchment in London. The performance of the adjusted precipitation estimates and the associated forecasts was tested using local rainfall and flow records. The results show that adjustments done at too large scales cannot provide tangible improvements in rainfall estimates and associated QPFs and runoff forecasts at small scales, such as those of urban catchments. Moreover, the results suggest that the KED adjusted rainfall estimates may be unsuitable for generating QPFs, as this method damages the continuity of spatial structures between consecutive rainfall fields

Enhancement of urban pluvial flood risk management and resilience through collaborative modelling: a UK case study

This paper presents the main findings and lessons learned from the development and implementation of a new methodology for collaborative modelling, social learning and social acceptance of flood risk management technologies. The proposed methodology entails three main phases: (1) stakeholder analysis and engagement; (2) improvement of urban pluvial flood modelling and forecasting tools; and (3) development and implementation of web-based tools for collaborative modelling in flood risk management and knowledge sharing. The developed methodology and tools were tested in the Cranbrook catchment (London Borough of Redbridge, UK), an area that has experienced severe pluvial (surface) flooding in the past. The developed methodologies proved to be useful for promoting interaction between stakeholders, developing collaborative modelling and achieving social acceptance of new technologies for flood risk management. Some limitations for stakeholder engagement were identified and are discussed in the present paper

Elektrohemijsko ispitivanje uticaja pirokatehola na Bray-Liebhafsky reakciju nakon oscilatornog perioda

Thanks to the great sensitivity of oscillating reactions to external perturbations, which primarily refers to different analyte addition, chemical oscillators have become very popular for analytic determination of “reactive” analytes, and thus expand their use to many areas, such as environmental, pharmacy, food science etc. This paper aims at an electrochemical examination of the pyrocatechol (analyte) influence on the Bray-Liebhafsky (BL) reaction after the oscillatory period, precisely after six regular oscillations. Pyrocatechol addition provokes the appearance of one more BL oscillation after the second induction period. For investigated BL system, in a range of pyrocatechol concentrations from 2.7 × 10-6 M to 1.2 × 10-4 M, the period between sixth and seventh oscillations shows linear dependence with added pyrocatechol concentration. The obtained regression equation can be a useful tool for analytical purposes and accordingly, potential determination of unknown pyrocatechol concentration.Zahvaljujući velikoj osetljivosti oscilatornih reakcija na spoljne perturbatore, koja se prvenstveno odnosi na dodavanje različitih analita, hemijski oscilatori postali su vrlo popularni za analitičko određivanje „reaktivnih“ analita, proširivši svoju primenu na mnoge naučne grane, poput zaštite zivotne sredine, farmacije, nauke o hrani itd. Ovaj rad ima za cilj elektrohemijsko ispitivanje uticaja pirokatehola (analita) na Bray-Liebhafsky (BL) reakciju nakon oscilatornog perioda, odnosno nakon šest pravilnih oscilacija. Dodatak pirokatehola izaziva pojavu još jedne BL oscilacije nakon drugog indukcionog perioda. Za ispitivani BL sistem, u opsegu koncentracija pirokatehola od 2,7 × 10-6 M do 1,2 × 10-4 M, period između šeste i sedme oscilacije pokazuje linearnu zavisnost od koncentracije dodatog pirokatehola. Dobijena kalibraciona jednačina se može koristiti u analitičke svrhe i shodno tome, za potencijalno određivanje nepoznate koncentracije pirokatehola.XII YuCorr International Conference, September 13-16, 2021, Tara Mountain, Serbia, [http://sitzam.org.rs/YUCORR/

A possible connection between phosphate tungsten bronzes properties and briggs-rauscher oscillatory reaction response

The calcium phosphate tungsten bronze (Ca-PWB) has been synthesized and characterized (TGA, DSC, XRPD, FTIR, SEM). The influence of solid insoluble materials Ca-PWB, as well as lithium doped (Li-PWB) and cation free phosphate tungsten (PWB) bronzes on the oscillatory Briggs-Rauscher (BR) reaction dynamics, is compared. The results show that doping with Li and Ca reduces sensitivity of the BR reaction towards bronzes addition. These findings suggest the usage of the BR reaction as an innovative method for testing of different properties of bronze material. The behavior of PWB in the BR reaction is significantly changed with divalent cation (Ca2+) doping. The reasons for the different bronzes behavior were found in their calculated unit cell volumes. Namely, the compressed Ca-PWB unit cell volume indicates the difficult availability of the active site for heterogeneous catalysis. Hence, the linear correlation (slope) of the BR oscillogram’s length (τosc) vs. mass of bronze in BR reaction might be considered as a new parameter for the evaluation of the bronzes catalytic activity.У овом раду синтетисана је и окарактерисана (TGA, DSC, XRPD, FTIR, SEM) нова калцијумом допирана фосфат волфрамова бронза (Ca-PWB). Испитан је и упоређен утицај фосфат волфрамове бронзе (PWB), литијумом допиране фосфат волфрамове бронзе (Li-PWB) и калцијумом допиране фосфат волфрамове бронзе (Ca-PWB) на осцилаторну динамику Briggs-Rauscher (БР) реакције. Резултати показују да допирање катјонима Li+ и Ca2+ смањује осетљивост БР реакције на додатак нерастворних бронзи, што се огледа у смањивању нагиба праве осцилаторног времена (τosc) БР реакције у функцији масе додате допиране бронзе. Добијени резултати сугеришу употребу БР реакције као иновативне методе за испитивање различитих својстава допираних и недопиране фосфат волфрамове бронзе. Разлози за различито понашање бронзи у осцилаторној реакцији пронађени су у различитим величинама јединичних ћелија PWB, Li-PWB и Ca-PWB. Наиме, најмања вредност, тј. сабијање јединичне ћелије допирањем калицијумом указује на тежу доступност активних места за хетерогену катализу. Каталитичка активност бронзи усмерена је ка реакцијама оксидације које укључују водоник-пероксид (један од реактаната БР реакције). Стога би се линеарна корелација (нагиб) τosc у функцији масе бронзе у БР реакцији могла сматрати новим параметром за процену каталитичке активности бронзе, али и других материјала

A smooth introduction to the wavefront set

The wavefront set provides a precise description of the singularities of a distribution. Because of its ability to control the product of distributions, the wavefront set was a key element of recent progress in renormalized quantum field theory in curved spacetime, quantum gravity, the discussion of time machines or quantum energy inequalitites. However, the wavefront set is a somewhat subtle concept whose standard definition is not easy to grasp. This paper is a step by step introduction to the wavefront set, with examples and motivation. Many different definitions and new interpretations of the wavefront set are presented. Some of them involve a Radon transform.Comment: 29 pages, 7 figure

Trakhtenbrot's Theorem in Coq, A Constructive Approach to Finite Model Theory

We study finite first-order satisfiability (FSAT) in the constructive setting of dependent type theory. Employing synthetic accounts of enumerability and decidability, we give a full classification of FSAT depending on the first-order signature of non-logical symbols. On the one hand, our development focuses on Trakhtenbrot's theorem, stating that FSAT is undecidable as soon as the signature contains an at least binary relation symbol. Our proof proceeds by a many-one reduction chain starting from the Post correspondence problem. On the other hand, we establish the decidability of FSAT for monadic first-order logic, i.e. where the signature only contains at most unary function and relation symbols, as well as the enumerability of FSAT for arbitrary enumerable signatures. All our results are mechanised in the framework of a growing Coq library of synthetic undecidability proofs

Indigo Carmine in a Food Dye: Spectroscopic Characterization and Determining Its Micro-Concentration through the Clock Reaction

Indigo carmine is a commonly used industrial blue dye. To determine its concentration in a commercially available food dye composed of a mixture of indigo carmine and D-glucose, this paper characterizes it through (ATR, KBr) FTIR micro-Raman as well as UV/Vis and clock: Briggs–Rauscher (BR) oscillatory reaction methods. The indigo carmine was detected in the bulk food dye only by applying micro-Raman spectroscopy, indicating a low percentage of the indigo carmine present. This research provides an improvement in the deviations from the experimental Raman spectrum as calculated by the B97D/cc-pVTZ level of theory one, resulting in a better geometrical optimization of the indigo carmine molecule compared to data within the literature. The analytical curves used to determine indigo carmine concentrations (and quantities) in an aqueous solution of food dye were applied by means of UV/Vis and BR methods. BR yielded significantly better analytical parameters: 100 times lower LOD and LOQ compared to commonly used UV/Vis. The remarkable sensitivity of the BR reaction towards indigo carmine suggests that not only does indigo carmine react in an oscillatory reaction but also its decomposition products, meaning that the multiple oxidation reactions have an important role in the BR’s indigo carmine mechanism. The novelty of this research is the investigation of indigo carmine using a clock BR reaction, opening new possibilities to determine indigo carmine in other complex samples (pharmaceutical, food, etc.)