The history of rainfall data time-resolution in a wide variety of geographical areas

Collected rainfall records by gauges lead to key forcings in most hydrological studies. Depending on sensor type and recording systems, such data are characterized by different time-resolutions (or temporal aggregations), ta. We present an historical analysis of the time-evolution of ta based on a large database of rain gauge networks operative in many study areas. Globally, ta data were collected for 25,423 rain gauge stations across 32 geo graphic areas, with larger contributions from Australia, USA, Italy and Spain. For very old networks early re cordings were manual with coarse time-resolution, typically daily or sometimes monthly. With a few exceptions, mechanical recordings on paper rolls began in the first half of the 20th century, typically with ta of 1 h or 30 min. Digital registrations started only during the last three decades of the 20th century. This short period limits investigations that require long time-series of sub-daily rainfall data, e.g, analyses of the effects of climate change on short-duration (sub-hourly) heavy rainfall. In addition, in the areas with rainfall data characterized for many years by coarse time-resolutions, annual maximum rainfall depths of short duration can be potentially underestimated and their use would produce errors in the results of successive applications. Currently, only 50% of the stations provide useful data at any time-resolution, that practically means ta = 1 min. However, a sig nificant reduction of these issues can be obtained through the information content of the present database. Finally, we suggest an integration of the database by including additional rain gauge networks to enhance its usefulness particularly in a comparative analysis of the effects of climate change on extreme rainfalls of short duration available in different locations

Equilibrium and kinetic studies of palladium(II) ions sorption onto Dowex resins

Palladium(II) sorption was studied in hydrochloric acid solutions with sodium chloride addition onto Dowex MSA-1 and Dowex MSA-2 resins by means of the static method. The dependence between the amount of palladium(II) ions sorbed at time tin a disequilibrium state (qt) as well as the sorption capacities (qe) and phases contact time were obtained. The results were applied in kinetic studies using the pseudo-fi rst (Lagergren equation) and pseudo-second order kinetic equations (linear form of Blanchard equation proposed by Ho, PSO). Moreover, the equilibrium studies were caried out at ambient temperature and fitted to the Langmuir and Freundlich isotherms. The AFM pictures of the surface of anion exchange resins before and after the loading process were also recorded. Both resins exhibit high selectivity towards palladium(II) ions. The sorption capacities are in the range 7–10 mg/g for both resins under discussion in all examined solutions. Th e pseudo-second order kinetic equation and the Langmuir isotherm show the best fit with the experimental data

Sorption of the acid dyes onto strongly basic anion exchanger: Kinetic and equilibrium studies

The strong base acrylic anion exchangers, Amberlite IRA-458, was used as an adsorbent for the investigation of acid dyes (Acid Orange 7, Acid Orange 10 and Acid Red 88) adsorption kinetics and isotherms. The pseudo-fi rst order and pseudo-second order kinetic models were used to analyze the kinetic data and good agreement between the experimental and calculated amounts of dye adsorbed at equilibrium were obtained for the pseudo-second order kinetic models for the entire investigated concentrations domain in the case all three investigated dyes. The adsorption equilibrium data were analyzed by the Langmuir and Freundlich isotherm models with the best fitting being the first one

Usuwanie toksycznych jonów metali ciężkich oraz metalobarwników z roztworów wodnych z wykorzystaniem jonitu oraz tlenku mineralnego

The aim of the study was to compare the removal efficiency of toxic heavy metal ions: chromium(VI), nickel(II) and copper(II) as well as metal-complex dyes from aqueous solution using Lewatite VPOC 1065 and AdsorbsiaTM As500. The point of zero charge (pHPZC) of both sorbents and the influence of the initial concentration on the sorption process of Ni(II), Cu(II), Cr(VI), C.I. Acid Red 183 (AR183), C.I. Reactive Blue 21 (RB21) and nickel(II) phthalocyanine-tetrasulfonic acid tetrasodium salt (NiPc-TSATSS) were studied to determine the maximum sorption capacity. Kinetic studies were also carried out for the most effective sorbent-sorbate systems. The concentration effect of both hydrochloric acid and auxiliaries on the removal yield was also taken into account. As was found, Lewatit VPOC 1065 can be successfully applied for the treatment of textile wastewaters containing metal complex dyes and heavy metal ions. The highest sorption capacity, qe = 816.1 mg/g, was found for C.I. Acid Red 183.Wśród zanieczyszczeń środowiska na szczególną uwagę zasługują metale ciężkie oraz metalobarwniki, które emitowane są do środowiska z różnych gałęzi przemysłu. Z uwagi na ich negatywny wpływ na organizmy żywe niezwykle istotnym jest ich usuwanie z wód i ścieków z wykorzystaniem różnych metod, wśród których adsorpcja odgrywa istotną rolę. Celem pracy było porównanie efektywności usuwania toksycznych jonów metali ciężkich: Cr(VI), Ni(II), Cu(II) oraz metalobarwników :C.I. Acid Red 183, C.I. Reactive Blue 21, soli tetrasodowej kompleksu nikluikwasu ftalocyjanino-tetrasulfonowego z roztworów wodnych z wykorzystaniem jonitu Lewatit VPOC 1065 oraz tlenku AdsorbsiaTM As500. Wyznaczono pHPZC obu sorbentów oraz zbadano wpływ stężenia początkowego na proces sorpcji badanych sorbatów oraz kinetykę procesu sorpcji dla najbardziej efektywnego układu sorbent-sorbat. W badaniach uwzględniono także wpływ stężenia kwasu chlorowodorowego oraz wpływ substancji pomocniczych na proces sorpcji

The effect of parallel hot windbox repowering on 387 MW fossil fuel power plant

The paper presents the concept of repowering in existing power plant. Among technologies for existing steam power plants, the hot windbox repowering is the fastest way to respond to the energy demand, improve efficiency and reduce the pollutants emissions. Thermodynamic analysis of power plant model with fossil boiler before and after hot windbox repowering, has been investigated using commercial software. The purpose of this work is to understand and analyze the effect of hot windbox repowering on 387 MW fossil fuel power plant as well as the effect of additional heat exchangers, which have been installed parallel with regeneration system to use the heat of boiler exhaust gases. In this way, after repowering the summary power of power plant in base load is 615 MW, which has been reached adding gas turbine (176.9 MW). To analyze the model, calculations were performed in 3 stages: 1) calculation and comparison of the thermodynamic parameters as well as carbon dioxide emissions of power plant model before and after repowering, 2) analysis of the optimal value of feed water mass flow through heat exchangers installed after economizer, 3) calculation of thermodynamic parameters in values 100%, 90%, 80% and 75% of fossil boiler heat loads

Comparison of Varion resins selectivity towards palladium(II) ions in hydrochloric acid solutions with sodium chloride addition

Ion exchange is Ion exchange is found more and more signifi cant importance in metal processing, and hydrometallurgy in general, not only for the removal of impurities but also for the reconcentration process of metal ions. The ion exchange method (dynamic method) was applied in the preconcentration of palladium(II) ions from the chloride solutions with sodium chloride addition. Varion resins such as the strongly basic anion exchange resins: Varion ADM and Varion ATM and the weakly basic anion exchange resin Varion ADAM were taken into account during the sorption process. The selectivity series were obtained based on the breakthrough curves of palladium(II) ions determined by means of dynamic method. Moreover, the distribution coefficients: weight and bed as well as the working anion exchange capacities were calculated. From the Varion resins — Varion ADAM is the most promising in the preconcentration of Pd(II)