Physical development trend and green space destruction in developing cities: a GIS approach

Green spaces considered natural remnants in urban environments play a key role in promoting environmental quality and forming a sustainable city. Nowadays, development of urban spaces has taken a hasty growth. In the meanwhile, the natural green spaces are severely damaged. The current study aims at investigating the trend of changes in green space of Tabriz City, the second large industrial city in Iran, on the basis of landscape ecology principles. In order to prepare the land-cover maps, Landsat TM and IRS LISS-III of the years 1989 and 2006 were applied. Alongside, landscape percentage metrics, the largest patch index, number of patches, patch density, edge density, total edge, class area and landscape shape index were also used to analyse the changes. Metric analysis of the landscape within the studied years revealed that a large part of the region has enjoyed a rapid growth (equivalent to 64.5 %) in constructions. As the obtained results showed, the smallest landscape percentage (3.9 %) in the study area is belonged to the municipal green space, while the largest landscape percentage (66 %) is allocated to the barren land. This shows that the constructions have not balanced with creation of new green spaces, and the lack of green space per capita continues to be felt.     

Ultrasound-assistant preparation of Cu-SAPO-34 nanocatalyst for selective catalytic reduction of NO by NH3

The influence of the various preparation methods of Cu-SAPO-34 nanocatalysts on the selective catalytic reduction of NO with NH₃ under excess oxygen was studied. Cu-SAPO-34 nanocatalysts were prepared by using four techniques: conventional impregnation (IM), ultrasound-enhanced impregnation (UIM), conventional deposition precipitation (DP) using NaOH and homogeneous deposition precipitation (HDP) using urea. These catalysts were characterized in detail by various techniques such as N₂-sorption, XRD, TEM, H₂-TPR, NH₃-TPD and XPS to understand the catalyst structure, the nature and the dispersed state of the copper species, and the acid sites for NH₃ adsorption. All of the nanocatalysts showed high activities for NO removal. However, the activities were different and followed the sequence of Cu-SAPO-34 (UIM) > Cu-SAPO-34 (HDP) > Cu-SAPO-34 (IM) > Cu-SAPO-34 (DP). Based on the obtained results, it was concluded that the NO conversion on Cu-SAPO-34 nanocatalysts was mainly related to the high reducibility of the isolated Cu^2 + ions and CuO species, the number of the acid sites and the dispersion of CuO species on SAPO-34.     

Treatment of Basic Red 29 dye solution using iron-aluminum electrode pairs by electrocoagulation and electro-Fenton methods

The aim of this study is the treatment of Basic Red 29 (BR29) dye solution using hybrid iron-aluminum electrodes by electrocoagulation and electro-Fenton methods. The effect of current density, initial pH, supporting electrolyte, H₂O₂, and initial dye concentration on dye removal efficiency was investigated, and the best experimental conditions were obtained. Time-coarse variation of UV-Vis spectra and toxicity and chemical oxygen demand (COD) removal were also examined at the best experimental conditions. Both systems were found very successful for the removal of BR29 dye. The removal efficiency of >95 % for BR29 dye solution was reached easily in a short time. At the best experimental conditions, for the initial BR29 concentration of 100 mg/L, >95 % BR29 dye and 71.43 % COD removal were obtained after 20 and 40 min of electrolysis, respectively. Additionally, toxicity results for electro-Fenton treatment of 100 mg/L BR29 were also very promising. According to the results obtained, although electro-Fenton is more effective, both systems can be used successfully to treat textile wastewater including dyes.     

Laboratory waste minimization by recovery of silver as nano-silver colloidal dispersion from waste silver chloride

The use of cyclic experiments, where the product of one reaction becomes the starting material for the next experiment, was proposed as an effective protocol for waste minimization in an educational lab. A simple, cheap and pollution-free method was developed for recovering silver as nano-silver colloidal dispersion from waste silver chloride in the laboratories of the Faculty of Health, Safety and Environment. Silver nanoparticles of the size 5–18 nm were recovered in the presence of sodium borohydride as a reducing agent and polyvinylpyrrolidone as a stabilizer agent. The nano-silver particles were studied for their formation, structure, stability and size using UV–Vis spectroscopy, transmission electron microscopy and dynamic light scattering techniques. The antibacterial assays of nanoparticles showed satisfactory results for Escherichia coli ATCC25922, Staphylococcus aureus ATCC 29213, and Acinetobacter baumanii (Clinical isolate). A laboratory experiment was designed in which students synthesize yellow colloidal silver solution from chemical waste silver chloride and estimate particle size using visible spectroscopy.     

PREDICTING EROSION AND DEPOSITION ON A STRIPMINED AND RECLAIMED AREA1

ABSTRACT A rill-interrill erosion model was applied to a mined and reclaimed area. Soil loss from the interrill areas was estimated by the Universal Soil Loss Equation (USLE). The model considers the fate and ultimate disposition of the sediment from interrill areas along with the fate and destination of soil materials detached by the rill flow. The net sediment loss was predicted by comparing, for a given flow, the amounts of eroded soil to rill transport capacity. When applied to a selected stripmined and reclaimed site the model displayed the location of contributing areas and the amount of erosion and deposition. The predicted areal distribution of erosion and deposition was compared to measured data. Agreement between the predicted and measured values was within 25 percent.     

Estimating and mapping forest biomass using regression models and Spot-6 images (case study: Hyrcanian forests of north of Iran)

Hyrcanian forests of North of Iran are of great importance in terms of various economic and environmental aspects. In this study, Spot-6 satellite images and regression models were applied to estimate above-ground biomass in these forests. This research was carried out in six compartments in three climatic (semi-arid to humid) types and two altitude classes. In the first step, ground sampling methods at the compartment level were used to estimate aboveground biomass (Mg/ha). Then, by reviewing the results of other studies, the most appropriate vegetation indices were selected. In this study, three indices of NDVI, RVI, and TVI were calculated. We investigated the relationship between the vegetation indices and aboveground biomass measured at sample-plot level. Based on the results, the relationship between aboveground biomass values and vegetation indices was a linear regression with the highest level of significance for NDVI in all compartments. Since at the compartment level the correlation coefficient between NDVI and aboveground biomass was the highest, NDVI was used for mapping aboveground biomass. According to the results of this study, biomass values were highly different in various climatic and altitudinal classes with the highest biomass value observed in humid climate and high-altitude class.     

Response curves of seventeen woody species to soil factors along a riparian forest in northern Iran

The aim of this study was to determine type of response curves for seventeen woody species (10 tree and 7 shrub species) to soil factors in an intact riparian forest in Safaroud River in northern Iran using HOF function. Data were collected along transects established perpendicular to the water flow on both sides of the river. Results indicated different responses for different woody species. The most common were symmetricunimodal response curves and curves showing an increase in occurrence probability after a certain value in form of a plateau. Bimodal curves were four times more frequent in riverside than forest interior area. It seems that river flow disturbances through frequent floods effect on species tolerance and optimum in riversides.