Vremenske i prostorne varijacije salaniteta podzemnih voda u ravnici Mazandaran, Iran, tijekom dugogodišnjeg razdoblja od 26 godina

Groundwater resources are one of the main sources of water supply for agricultural sector in Iran. Therefore, this study aimed to investigate the situation of groundwater salinity in Mazandaran for use in agriculture. In this study, statistical analysis of collected data, proper semivariogram model selection, cross validation of predictions and preparing probabilistic and zoning maps using geostatistical tools in the ArcGIS software, were performed. To investigate the spatial variations and preparing zoning maps of water salinity, ordinary kriging (OK) was used and the zoning maps were prepared. Spatial structure of electrical conductivity (EC) assessment showed a moderate spatial dependence in most years. Zoning and probabilistic maps of EC showed that the salinity of groundwater will be added and the most probable salinity is related the lowland areas in the eastern part of the plain. The use of this groundwater for irrigation in the long term can decrease the rice yield and faced rice production with a serious risk. The results of the Mann-Kendall and the Sen tests indicated a decreasing trend in the area of groundwater with EC higher than one dS/m in Mazandaran plain that this expressing an improvement in the quality of groundwater in the plain.Resursi podzemnih voda jedan su od glavnih izvora vodoopskrbe poljoprivrednog sektora u Iranu. Stoga je ova studija usmjerena na istraživanje stanja saliniteta podzemnih voda u Mazandaranu koje se koriste u poljoprivredi. U ovoj studiji provedena je: statistička analiza prikupljenih podataka, odabir pravilnog modela semivariograma, unakrsno potvrđivanje predviđanja i pripremanje probabilističkih i zoniranje karata koristeći geostatističke alate u ArcGIS softveru. Da bi se istražile prostorne varijacije i pripremile karte slanosti vode korišteno je obično krigiranje (OK) i pripremljene su karte zoniranja. Prostorna struktura procjene električne provodljivosti (EC) pokazala je umjerenu prostornu ovisnost u većini godina. Zoniranje i probabilističke karte električne vodljivosti pokazale su da će se dodati slanost podzemnih voda, a najvjerojatnija slanost povezana je s nizinskim područjima u istočnom dijelu ravnice. Korištenje takvih podzemnih voda za navodnjavanje dugoročno može smanjiti prinos riže i proizvodnju s rižom s ozbiljnim rizikom. Rezultati ispitivanja pomoću Mann-Kendall-ovog i Senovog testa ukazali su na trend pada podzemnih voda s električnom vodljivošću 1 dS/m, što upućuje na poboljšanje kvalitete podzemnih voda u ravnici Mazandaran

Modification of immobilized titanium dioxide nanostructures by argon plasma for photocatalytic removal of organic dyes

The aim of this study was to modify surface properties of immobilized rutile TiO 2 using Argon cold plasma treatment and to evaluate the performance of the catalyst in photocatalytic elimination of synthetic dyes in UV/TiO 2 /H 2 O 2 process. The surface-modified TiO 2 was characterized by XRD, EDX, SEM, UV-DRS and XPS analyses. Response surface methodology was adopted to achieve high catalyst efficiency by evaluating the effect of two main independent cold plasma treatment parameters (exposure time and pressure) on surface modification of the catalyst. The increase of the plasma operation pressure led to higher decolorization percentage, while the increase of plasma exposure time decreased the decolorization efficiency. RSM methodology predicted optimum plasma treatment conditions to be 0.78 Torr and 21 min of exposure time, which resulted in decolorization of 10 mg/L solution of the malachite green solution by 94.94 in 30 min. The plasma treatment decreased the oxygen to titanium ratio and caused oxygen vacancy on the surface of the catalyst, resulting in the superior performance of the plasma-treated catalyst. Pseudo first-order kinetic rate constant for the plasma-treated catalyst was 4.28 and 2.03 times higher than the rate constant for the non-treated photocatalyst in decolorization of aqueous solutions of malachite green and crystal violet, respectively. © 2019 by the authors

A novel ensemble artificial intelligence approach for gully erosion mapping in a semi-arid watershed (Iran)

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. In this study, we introduced a novel hybrid artificial intelligence approach of rotation forest (RF) as a Meta/ensemble classifier based on alternating decision tree (ADTree) as a base classifier called RF-ADTree in order to spatially predict gully erosion at Klocheh watershed of Kurdistan province, Iran. A total of 915 gully erosion locations along with 22 gully conditioning factors were used to construct a database. Some soft computing benchmark models (SCBM) including the ADTree, the Support Vector Machine by two kernel functions such as Polynomial and Radial Base Function (SVM-Polynomial and SVM-RBF), the Logistic Regression (LR), and the Naïve Bayes Multinomial Updatable (NBMU) models were used for comparison of the designed model. Results indicated that 19 conditioning factors were effective among which distance to river, geomorphology, land use, hydrological group, lithology and slope angle were the most remarkable factors for gully modeling process. Additionally, results of modeling concluded the RF-ADTree ensemble model could significantly improve (area under the curve (AUC) = 0.906) the prediction accuracy of the ADTree model (AUC = 0.882). The new proposed model had also the highest performance (AUC = 0.913) in comparison to the SVM-Polynomial model (AUC = 0.879), the SVM-RBF model (AUC = 0.867), the LR model (AUC = 0.75), the ADTree model (AUC = 0.861) and the NBMU model (AUC = 0.811)

The generalized second law of gravitational thermodynamics on the apparent horizon in f(R)-gravity

We investigate the generalized second law (GSL) of thermodynamics in the framework of $f(R)$-gravity. We consider a FRW universe filled only with ordinary matter enclosed by the dynamical apparent horizon with the Hawking temperature. For a viable modified gravity model as $f(R)=R-\alpha/R+\beta R^{2}$, we examine the validity of the GSL during the early inflation and late acceleration eras. Our results show that for the selected $f(R)$-gravity model minimally coupled with matter, the GSL in the early inflation epoch is satisfied only for the special range of the equation of state parameter of the matter. But in the late acceleration regime, the GSL is always respected.Comment: 10 pages, accepted by Europhys. Lett. 201