Experimental study on micro-electrolysis technology for pharmaceutical wastewater treatment

Experiments were conducted to study the role of micro-electrolysis in removing chromaticity and COD and improving the biodegradability of pharmaceutical wastewater. The results showed that the use of micro-electrolysis technology could remove more than 90% of chromaticity and more than 50% of COD and greatly improved the biodegradability of pharmaceutical wastewater. Lower initial pH could be advantageous to the removal of chromaticity. A retention time of 30 minutes was recommended for the process design of micro-electrolysis.

Controlled-source electromagnetic data processing based on gray system theory and robust estimation

We propose a novel method that combines gray system theory and robust M-estimation method to suppress the interference in controlled-source electromagnetic data. We estimate the standard deviation of the data using a gray model because of the weak dependence of the gray system on data distribution and size. We combine the proposed and threshold method to identify and eliminate outliers. Robust M-estimation is applied to suppress the effect of the outliers and improve the accuracy. We treat the M-estimators of the preserved data as the true data. We use our method to reject the outliers in simulated signals containing noise to verify the feasibility of our proposed method. The processed values are observed to be approximate to the expected values with high accuracy. The maximum relative error is 3.6676%, whereas the minimum is 0.0251%. In processing field data, we observe that the proposed method eliminates outliers, minimizes the root-mean-square error, and improves the reliability of controlled-source electromagnetic data in follow-up processing and interpretation.

Quo Vadis Archimedean Turbines Nowadays in Greece, in the Era of Transition？

According to recent hydropower inventories, the first aim of this paper is to prove that Greece is a real ＂Archimedean Soft Small Hydro Development Terra Incognita＂. It is a country in the Era of Transition of nowadays, having an important unexploited hydropower potential of several TWh and thousands of MW. The second goal is to present the results of rediscovering the old screw pumps and the always-modern Archimedean cochlear screw ideas as a series of soft hydropower turbines with inclined axis rotors and floating spiral screw devices. By following the similarity methodology, a few small-scale models of cochlear rotors were designed, developed and tested in an Armfield hydraulic channel. The conventional and unconventional, low or zero-head screw turbines, could efficiently harness the important and unexploited Greek small potential and kinetic hydraulic energy of all the natural watercourses, the man-made open urban or rural channels and the most important tidal or sea currents, producing useful green electricity. The very promising low-head hydropower inventory of Greece, the preliminary experimental results and the research studies of cochlear projects in watercourses, hydraulic works, tidal conditions of Euripus Strait and in the mysterious ＂Sea River Current of Cephalonia＂, seems to give a good answer to the question ＂Quo Vadis Archimedes nowadays in Greece, in the Era of Transition？＂.

The electrochemical stability of ionic liquids and deep eutectic solvents

Room temperature ionic liquids （ILs） composed of cations and anions, as well as deep eutectic solvents （DESs） composed of hydrogen bond donors （HBDs） and hydrogen bond acceptors （HBAs）, are regarded as green solvents due to their low volatility. They have been used widely for electrochemically driven reactions because they exhibit high conductivity and excellent elec- trochemical stability. However, no systematic investigations on the electrochemical potential windows （EPWs）, which could be used to characterize the electrochemical stability, have been reported. In this regard, the EPWs of 33 ILs and 23 DESs have been studied utilizing cyclic voltammetry （CV） method and the effects of structural factors （cations and anions of ILs, and HBDs and HBAs of DESs） and external factors （electrode, water content） on the EPWs have been comprehensively investi- gated. The electrochemical stability of selected 1Ls comprising five traditional cations, namely imidazolium, pyridinium, pyr- rolidinium, piperidinium and ammonium and 13 kinds of versatile anions was studied. The results show that for ILs, both cati- on and anion play an important role on the reductive and oxidative potential limit. For a same IL at different working electrode, for example, glassy carbon （GC）, gold （Au） and platinum （Pt） electrode, the largest potential window is almost observed on the GC working electrode. The investigations on the EPWs of choline chloride （ChCl）, choline bromide （ChBr）, choline iodide （ChI）, and methyl urea based DESs show that the DES composed of ChCl and methyl urea has the largest potential window. This work may aid the selection of ILs or DESs for use as a direct electrolyte or a solvent in electrochemical applications.