We aim at splitting a given multiply connected polygon into a set of convex quadrilaterals. Our approach consists in repeatedly removing quadrilaterals from the given polygon. We will first derive theoretical results pertaining to quadrangulation of simple polygons from the usual 2-ear theorem. Unfortunately, that theorem holds only for simply connected polygons while we are interested in quadr...

Contaminants in water are classified into different types based on their physical and chemical properties. Thus, more than one type of sorbents may be needed for their removal. In this article, a combination of vermiculite with palygorskite was studied for their simultaneous removal of ammonium and humic acid from simulated groundwater. Batch results showed that the Langmuir model described amm...

Trace organic compounds (TrOCs), mostly found in secondary effluents, have a potential impact on the environment, affecting surface water, groundwater, and especially aquatic ecosystems. The present study focuses on oxidation of five selected TrOCs in column experiments, by simulating Soil Aquifer Treatment (SAT) integrated with Fenton-like reaction, using Granular Ferric Hydroxide (GFH) as a c...

Lignite is an abundant carbon material with a variable surface structure and low cation density The introduction of metal (hydr)oxide phases has improved the anionic binding potential lignite. In this study, activated lignite (A−L), Ca2+−modified (Ca−L), (Ca−A−L) were synthesized to remove aqueous phosphate. was first (KOH: lignite, mass ratio, 3:1) at 750 ºC prepare A−L, improving its area by ...

This paper introduces a new off-line sample preparation that eliminates carbohydrates from amino acid samples containing a high carbohydrate content before analysis by anion-exchange chromatography and integrated pulsed amperometric detection. First, the sample is introduced into a cation-exchange column in the hydrogen form. Carbohydrates are removed completely using 0.02% formic acid as a tra...

An on-line pretreatment liquid chromatography-tandem mass spectrometry (LC-MS/MS) system was developed for the analysis of chloramphenicol (CAP) in royal jelly. A novel methylcellulose-immobilized restricted access media column with a higher-pressure capability of 60 MPa (MC-ODS HP) was developed for the effective removal of proteins and other compounds in the sample matrix. CAP in a sample sol...

Sarkhoon gas plant, located in south of Iran, has been installed to removal H2S contained in a high pressure natural gas stream. The solvent used for the H2S removal from gaseous stream is 34% by weight (wt%) Di-ethanol amine (DEA) solutions. Due to increasing concentration of heat stable salt (HSS) in solvent, corrosivity of amine solution had been increased. Reports indicated that there was c...

background: water filtration units have been faced problems in water turbidity removal related to their media, which is determined by qualitative indices. moreover, current qualitative indices such as turbidity and escaping particle number could not precisely determine the efficiency of the media in water filtration, so defining new indices is essential. in this study, the efficiency of anthrac...

Langmuir, Removal Efficiency. Abstract—Heavy metals are hazardous elements in aqueous solutions which threaten the living thing organisms. Steel making plant is among the industries which may generate high amounts of pollutants and can possess high values of heavy metals. In this research granular activated carbon material is used in two different types: 1) column made of separate layers of act...