Dimensional Stability and Water Uptake Properties of Cement-Bonded Wood Composites

This study was carried out to explore the possibility of making cement-bonded composite building products using eucalypt (Eucalyptus camaldulensis) and poplar (Populus deltoides). The experimental design consisted of three treatments—mixture of fibrous materials, cement and calcium chloride (CaCl₂) contents. Some physical properties, vis. water absorption (WA) and thickness swelling (TS), were investigated. The ratio of woodwool : cement was 40:60 and 60:40 by weight. Results showed that, water uptake increased with increasing woodwool content. In addition, boards fully made with poplar woodwools had superior properties compared to the eucalypt and mixed woodwools. The presence of eucalypt woodwools in mixture of fibrous materials typically resulted in increase in TS and WA. It is interesting to note that a dose of 5% of CaCl₂ by weight of cement can enhance the effect of cement. Application of Duncan’s Multiple Range Test for the mean values of the results showed that the effects of all variables and their interactions on the mechanical properties in terms of TS and WA were highly significant.     

Fish Bone as a Low-Cost Adsorbent for Dye Removal from Wastewater: Response Surface Methodology and Classical Method

This research studied the application of fish bone as a low-cost adsorbent for the removal of two basic dyes (C.I. Basic Blue 41 and C.I. Basic Yellow 28) from textile wastewaters. The surface morphology and functional groups of the fish bone was studied by scanning electron microscopy and Fourier transform infrared, respectively. The experiments were designed in two methods: classical method and response surface methodology (RSM). The effect of operating parameters including pH, initial dye concentration, adsorbent dosage, and inorganic salts was investigated by both methods. The optimum conditions to satisfy 75 % of dye removal for both dyes were predicted by RSM method and the results were very close to the experimental values. So, it was concluded that the fish bone can be used as a low-cost adsorbent for dye removal from effluents.     

Environmental protection stability of river bed and banks using convex, concave, and linear bed sills

River bed scourings are a major environmental problem for fish and aquatic habitat resources. In this study, to prevent river bed and banks from scouring, different types of bed sills including convex, concave and linear patterns were installed in a movable channel bed in a laboratory flume. The bed sills were tested with nine different arrangements and under different flow conditions. To find the most effective bed sill pattern, the scouring depth was measured downstream of the bed sill for a long experimental duration. The scour depth was measured at the middle and at the end of each experimental test for different ratios of the arch radius to the channel width $(r/\emph{w})$ . The experimental results indicated that the convex pattern with $r/\emph{w}=0.35$ produced minimum bed scouring depth at the center line whereas the concave pattern with $r/\emph{w}=0.23$ produced the minimum scour depth at the wall banks. Therefore, the convex pattern was the most effective configuration for prevention of scouring at the center line of the river while the concave pattern was very effective to prevent scouring at the river banks. These findings can be suggested to be used in practical applications.     

Petroleum pollution in mangrove forests sediments from Qeshm Island and Khamir Port—Persian Gulf, Iran

The concentrations of total polycyclic aromatic hydrocarbons (?PAHs) and 22 individual PAH compounds in 42 surface sediments collected from the mangrove forest of Qeshm Island and Khamir Port (Persian Gulf) were analyzed. ?PAHs concentrations ranged from 259 to 5,376 ng?g^?1 dry weight with mean and median values of 1,585 and 1,146 ng?g^?1, respectively. The mangrove sediments had higher percentages of lower molecular weight PAHs and the PAH profiles were dominated by naphthalene. Ratio values of specific PAH compounds were calculated to evaluate the possible source of PAH contamination. This ratios suggesting that the mangrove sediments have a petrogenic input of PAHs. Sediment quality guidelines were conducted to assess the toxicity of PAH compounds. The levels of total PAHs at all of stations except one station, namely Q₆, were below the effects range low. Also, concentrations of naphthalene in some stations exceeded the effects range median.