Flow estimations for the Sohu Stream using artificial neural networks

In this study, daily rainfall–runoff relationships for Sohu Stream were modelled using an artificial neural network (ANN) method by including the feed-forward back-propagation method. The ANN part was divided into two stages. During the first stage, current flows were estimated by using previously measured flow data. The best network architecture was found to utilise two neurons in the input layer (the delayed flows from the first and second days), two hidden layers, and one output layer (the current flow). The coefficient of determination (R ²) in this architecture was 81.4%. During the second stage, the current flows were estimated by using a combination of previously measured values for precipitation, temperature, and flows. The best architecture consisted of an input layer of 2 days of delayed precipitation, 3 days of delayed flows, and temperature of the current. The R ² in this architecture was calculated to be 85.5%. The results of the second stage best reflected the real-world situation because they accounted for more input variables. In all models, the variables with the highest R ² ranked as the previous flow (81.4%), previous precipitation (21.7%), and temperature.     

Seismic hazard analysis of Mersin Province,Turkey using probabilistic and statistical methods

Nearly 108-km lengths of Mersin shores are composed of natural beaches. The region is located between major tourist centers. In the future, this region is thought to be built with a great number of tourist facilities. Turkey’s largest seaport, Ata? refinery (Mersin International Port) is located in Mersin. Recently, Mersin is becoming of great importance to Turkey as the latter plans to construct its second nuclear power plant in the region. Therefore, as nuclear power plants are built to withstand environmental hazards, it is very important to analyze the seismic risk of the areas where the nuclear power plant will be constructed. The region is located between the East Anatolian Fault Zone and Center Anatolian Fault Zone. Based on the Turkey Earthquake Regions Map, Mersin is divided into second-, third-, and fourth-degree earthquake regions. In this study, we sampled earthquakes of magnitude of 4.0 or greater between 01 Jan 1900 and 31 Dec 2010 in the area; seismic hazard of Mersin province was estimated with probabilistic and statistical methods. The study area was selected as the coordinates between 36.03° and 37.42° North and 32.57° and 35.16° East. On the study area, different scaled magnitude values in the last 110 years converted to a common scale (Mw) and earthquake catalog was re-compiled and also seismic sources that may affect the area was determined. In this study, the seismic hazards of the region were obtained using the methods of probability and statistics. This study used three different attenuation relationships. Using the attenuation relationships suggested by Boore et al. (Seismol Res Lett 68(1):128–153, 1997) and Kalkan and Gülkan (Earthquake Spectra 20:1111–1138, 2004), the largest ground acceleration which corresponds to a recurrence period of 475 years was found as 0.08–0.09 g and Akkar and Ça?nan (Bull Seismol Soc Am 100 6:2978–2995, 2010), 0.04 g for bedrock at the central district. When computing for seismic hazard curves, Mut district appears to have a greater seismic hazard compared with other districts. Moreover, according to the attenuation relationships, seismic hazard curves corresponding to a recurrence period of 475 years were obtained for the Mersin Central, Mut, Erdemli, Çaml?yayla, and Tarsus districts.     

Spatial Distribution of SO2, NO2, and O3 Concentrations in an Industrial City of Turkey Using a Passive Sampling Method

Ambient concentrations of sulfur dioxide (SO₂), nitrogen dioxide (NO₂), and ozone (O₃) were measured at 51 sampling points by passive sampling technique in Kocaeli, an important industrial city in Turkey. Samples were analyzed by UV‐spectrophotometry for NO₂ and O₃ and by ion chromatography for SO₂, respectively. Concentrations of SO₂, NO₂, and O₃ were determined to investigate their spatial distribution and source characterization. The sampling campaigns revealed an average concentration of 8 µg/m³ (max. 82 µg/m³) for SO₂, and 14 µg/m³ (max. 40 µg/m³) for NO₂, in summer; while average winter concentrations were 25 µg/m³ (max. 61 µg/m³) for SO₂, and 50 µg/m³ (max. 100 µg/m³) for NO₂. The maximum ozone concentrations were determined to be 86 µg/m³ in summer and 61 µg/m³ in winter downwind of the source areas of the precursor pollutant emissions. The results showed that NO₂ and SO₂ concentrations in industrial and urban areas were two to four times higher compared with rural areas in the summer and winter. In the light of the information obtained from the spatial interpolation of the pollutant concentrations, a selection of appropriate locations for continuous monitoring was suggested according to the European Community (EU) directives.     

M5 model tree application in daily river flow forecasting in Sohu Stream, Turkey

This study investigate the potential of M5 model tree in predicting daily stream flows in Sohu river located within the municipal borders of Ankara, Turkey. The results of the M5 model tree was compared with support vector machines. Both modelling approaches were used to forecast up to 7-day ahead stream flow. A comparison of correlation coefficient and root mean square value indicates that M5 model tree approach works equally well to the SVM for same day discharge prediction. The M5 model tree also works well up to 7-day ahead discharge forecasting in comparison of SVM with this data set. An advantage of using M5 model tree approach is the availability of simple linear models to predict the discharge as well use of less computational time.     

Field experiments on wave propagation and vibration isolation by using wave barriers

In this paper, the obtained results from the experimental studies describe the basic characteristics of wave propagation and ability of possible measures to reduce the impact of soil vibrations on structural response for both active and passive isolation cases. A series of field tests on the foundation vibrations generated by electrodynamic shaker are performed to examine the screening efficiency of open and in-filled trench barriers which are constructed for full-scale measurement. From field measurements of amplitude with and without the barrier, the amplitude reduction ratio is estimated at different points of interest. Wave propagating characteristics and frequency-dependent screening effects of the wave barriers are investigated according to various isolation material stiffnesses. The remarkable outcomes from these experimental studies can be briefly generalized as follows: backfilled trench with softer material than soil is more effective for the passive isolation than the active one. The reduction effects of wave barriers depend on the frequency of vibration source for both passive and active isolation cases. In-situ measurements confirm that vibration screening systems using open or in-filled trench barriers can be applied as a reduction measure for soil vibrations due to a moving load which is considered as stationary wave source in this problem.     

Work of Adhesion of Thin Spray-On Liners

The interface property known as work of adhesion incorporates both adhesion and effective bond width, which are two important design parameters in thin spray-on liner (TSL) support design. The value of this parameter is yet to be recognized by the mining industry and liner manufacturers. The importance of this parameter is introduced in this study. A new methodology using pull-out load–displacement data was developed to calculate the work of adhesion between a TSL and a substrate. Tests were performed using Tekflex as a liner material, which was applied to concrete, granite or sandstone substrate. It was found that a Tekflex liner, when sprayed onto substrates, will likely have work of adhesion values around 777–973?N/m depending on the type of substrate. In addition, for the first time in TSL literature, an effective bond width calculation is introduced in this study. It was found that Tekflex has average effective bond width of 0.7?mm on different substrates. Liner manufacturers should measure and document work of adhesion for their products on a standard substrate.     

System Performance in UASB Reactors Receiving Increasing Levels of Sulfate

Glucose‐fed high‐rate UASB reactors were tested at three COD/SO₄ ratios and hydraulic retention times to promote sulfate reducing activity and observe the effects on reactor performance. Different COD/SO₄ ratios (20, 10, and 5) resulted in changes in organic matter removal, methane production, alkalinity, dissolved sulfide and biomass concentrations and profile. The COD removal dropped from 95 to 80–84 % at the lowest COD/SO₄ ratio. Sulfate was removed at 79 to 89 % at the highest ratio and dropped to 72 to 74 % with increasing sulfate loading. Alkalinity was produced at higher levels with increasing sulfate loading. Specific methane production dropped with decreasing hydraulic retention times. Sulfate‐reducing activity used a maximum of 11.7 % of organic matter at the highest sulfate loading level, producing a slight shift to sulfate‐reducing activity in the substrate competition between sulfate‐reducing bacteria and methanogens. Increased sulfate loading at COD/SO₄ ratios of 10 and 5 caused deterioration of the concentration profile of the sludge, resulting in biomass washout and decreased volatile fraction of biosolids in the reactors.     

Spatial variations of fundamental seismotectonic parameters for the earthquake occurrences in the Eastern Mediterranean and Caucasus

Natural Hazards - In this study, a comprehensive statistical analysis was made for different parts of the world. For this purpose, fundamental seismotectonic earthquake parameters such as b-value,...