An Analysis of Reducing Perchloroethylene Emissions in the Urban Environment: A Case Study of Taiwan

Selected volatile organic compounds (VOCs) emitted from commercial activities and industrial processes have been classified as hazardous air pollutants, posing a potential health risk in the urban environment. In this respect, perchloroethylene (PCE), a suspected human carcinogen, is the most noticeable compound because it is widely used in laundries and hotels as a dry‐cleaning solvent. The objective of this paper was to quantify the emissions of PCE and other petroleum‐based solvents from dry cleaning business in illustration of the regulatory infrastructure of reducing PCE exposure in the environment of Taiwan. Based on the Emission Factors (AP‐42) method, the emissions of the non‐methane hydrocarbons (NMHCs) from dry cleaning business had decreased from 5100 metric tons in 1997 to 2800 metric tons in 2007. The success of significant reduction of NMHCs in Taiwan has been ascribed to the fact that Taiwan established the relevant regulations at the end of the 1990s. From the data on the industrial/commercial demand for PCE and the emission inventories of NMHCs from dry cleaning business, the reduction of PCE emissions will show a declining trend in the near future.     

Recovery of Phosphate Sludge as Concrete Supplementary Material

The automotive industry plays a major role in the worldwide economy and represents an opportunity to increase the performance of the Turkish economy. Phosphating units in the automotive manufacturing plants generate phosphate sludge as waste, which is classified as hazardous waste in the European Waste Catalogue. Phosphate sludge must be disposed of in licensed disposal plants according to the current environmental regulations. Solidification/stabilization (S/S) is a widely used treatment technology for the disposal of hazardous wastes. Portland cement is used for the solidification and stabilization processes to immobilize Ni and Zn in the phosphate sludge as well as to create construction material to be used as cobble stone for pavement. Examination of products obtained by S/S processes is performed for two points: to determine the quality and to assess the environmental impacts. The phosphate sludge samples are subjected to chemical characterization and a size distribution analysis leaching test. Concrete for cobble stone was produced by the S/S process with the addition of phosphate sludge to replace sand. Tests for the quality of the product were carried out to determine compressive strength, permeability, and elasticity. At the end of the leaching test, elution concentrations of Zn and Ni while using water with pH values of 4.0, 5.4, and 9.0 were determined to be under the limit of inert material properties. Use of phosphate sludge should be considered as a sand replacement in the proportion of 1% of phosphate sludge to cement in concrete production, such as for cobble stone for pavement, without any adverse environmental impacts.     

Fast free surface multiples attenuation workflow for three-dimensional ocean bottom seismic data

Water multiples can be very strong and contaminate the primary reflections. This can cause problems in the processing flow and the interpretation of the subsurface image. Hence, multiples suppression is an important part of the preprocessing flow. We present a fast workflow for attenuation of free surface related multiples for 2D and 3D ocean bottom seismic data based on the wave equation approach. Included in the workflow are: 1. Calibration of the pressure and vertical velocity components by using wavefield splitting. 2. Data interpolation by using offset projection. 3. Fast Radon transform by using fast fractional Fourier transform. Advantages of this workflow are that it is fast, efficient and the only requirements are the recording of both pressure and vertical particle components at some point below the source in the water column.     

Source Parameters for 1999 North Anatolian Fault Zone Aftershocks

We develop a data set of aftershock recordings of the 1999, M = 7.4 Izmit and M = 7.2 Duzce (Turkey) earthquakes to study their source parameters. We combined seismograms from 44 stations maintained by several sources (organizations) to obtain a unified data set of events (2.1 ≤ M_w ≤ 5.5). We calculate source parameters of these small earthquakes by two methods that use different techniques to address the difficulty in obtaining source spectra for small earthquakes subject to interference from site response. One method (program NetMoment (NM), Hutchings, 2004) uses spectra of direct S waves in a simultaneous inversion of local high-frequency network data to estimate seismic moment, source corner frequency (f_c), site attenuation (k) and whole-path Q. This approach takes advantage of the source commonality in all recordings for a particular earthquake by fitting a common Brune source spectrum to the data with a and individual k. The second approach (Mayeda et al., 2003) uses the coda method (CM) to obtain “nonmodel-based” source spectra and moment estimates from selected broadband recording sites. We found that both methods do well for events that allow the comparison with seismic moment estimates derived from waveform modeling. Also, source spectra obtained from the two methods are very closely matched for most of the events they have in common. We use an F test to examine the trade-off between k and f_c picks identified by the direct S-wave method. About half of the events could be constrained to have less than a 50% average uncertainty in f_c and k. We used these source spectra solutions to calculate energy and apparent stress and compare these to estimates from the selected “good quality” source spectra from CM. Both studies have values mutually consistent and show a similar increase in apparent stress with increasing moment. This result has added merit due to the independent approaches to calculate apparent stress. We conclude that both methods are at least partially validated by our study, and they both have usefulness for different circumstances of recording local small earthquakes. CM would work well in studies for which there is a broad magnitude range of events and NM works well for local events recorded by band-limited recorders.     

Source mechanism and stress analysis of 23 October 2011 Van Earthquake (Mw = 7.1) and aftershocks

On 23 October 2011 at 1341 local time, a strong earthquake (Mw?=?7.1) occurred east of Lake Van (KOERI; Kandilli Observatory and Earthquake Research Institute). The focal parameters of the main shock and 29 aftershocks with M?≥?4.0 were obtained from regional broadband seismic data from KOERI network by using Regional Moment Tensor Inversion Code (Dreger 2002). It is confirmed that the main shock had thrust faulting mechanism. The stress tensor analysis was completed using the focal mechanism solutions and the software developed by (Gephart Comp Geosci 16: 953-989, 1990). The maximum principal stress (P compressional) of the main shock is aligned in a N-S (NNW/SSE) direction and the tensional axis (T dilatation) is aligned in an E-W (ENE-WSW) direction. The b value is calculated as 0.96 using the maximum likelihood method (Utsu 1999).     

Experimental investigation on the grain-scale compression behavior of loose wet granular material

The behavior of model granular materials (glass beads) wetted by a small quantity of liquid forming capillary bridges is studied by one-dimensional compression test combined with X-ray computed tomography (XRCT) observation. Special attention is paid to obtain very loose initial states (initial void ratio of about 2.30) stabilized by capillary cohesion. XRCT-based analyses involve spherical particle detection adapted to relatively low-resolution images, which enable heterogeneities to be visualized and microstructural information to be collected. This study on an ideal material provides an insight into the macroscopic compression behavior of wet granular materials based on the microstructural change, such as pore distance distribution, coordination number of contacts, coordination number of neighbors and number of contacts per grain.

     

A hybrid machine learning ensemble approach based on a Radial Basis Function neural network and Rotation Forest for landslide susceptibility modeling: A case study in the Himalayan area,India

In this paper, a hybrid machine learning ensemble approach namely the Rotation Forest based Radial Basis Function (RFRBF) neural network is proposed for spatial prediction of landslides in part of the Himalayan area (India). The proposed approach is an integration of the Radial Basis Function (RBF) neural network classifier and Rotation Forest ensemble, which are state-of-the art machine learning algorithms for classification problems. For this purpose, a spatial database of the study area was established that consists of 930 landslide locations and fifteen influencing parameters (slope angle, road density, curvature, land use, distance to road, plan curvature, lineament density, distance to lineaments, rainfall, distance to river, profile curvature, elevation, slope aspect, river density, and soil type). Using the database, training and validation datasets were generated for constructing and validating the model. Performance of the model was assessed using the Receiver Operating Characteristic (ROC) curve, area under the ROC curve (AUC), statistical analysis methods, and the Chi square test. In addition, Logistic Regression (LR), Multi-layer Perceptron Neural Networks (MLP Neural Nets), Naïve Bayes (NB), and the hybrid model of Rotation Forest and Decision Trees (RFDT) were selected for comparison. The results show that the proposed RFRBF model has the highest prediction capability in comparison to the other models (LR, MLP Neural Nets, NB, and RFDT); therefore, the proposed RFRBF model is promising and should be used as an alternative technique for landslide susceptibility modeling.     

Seismotectonic database of Turkey

Turkey is located in one of the most seismically active regions in the world. Characterizing seismic source zones in this region requires evaluation and integration of geological, geophysical, seismological and geodetical data. This first seismotectonic database for Turkey presented herein was prepared, under the framework of the National Earthquake Strategy and Action Plan—2023. The geographic information system (GIS)-based database includes maps of active faults, catalogues of instrumental and historical earthquakes, moment tensor solutions and data on crustal thickness. On the basis of these data, 18 major seismotectonic zones were delineated for Turkey and the surrounding region. The compilation and storage of the seismotectonic data sets in a digital GIS will allow analyses and systematic updates as new data accrete over time.     

A fractal model for streaming potential coefficient in porous media

Streaming potential is the result of coupling between a fluid flow and an electric current in porous rocks. The modified Helmholtz–Smoluchowski equation derived for capillary tubes is mostly used to determine the streaming potential coefficient of porous media. However, to the best of our knowledge, the fractal geometry theory is not yet applied to analyse the streaming potential in porous media. In this article, a fractal model for the streaming potential coefficient in porous media is developed based on the fractal theory of porous media and on the streaming potential in a capillary. The proposed model is expressed in terms of the zeta potential at the solid?liquid interface, the minimum and maximum pore/capillary radii, the fractal dimension, and the porosity of porous media. The model is also examined by using another capillary size distribution available in published articles. The results obtained from the model using two different capillary size distributions are in good agreement with each other. The model predictions are then compared with experimental data in the literature and those based on the modified Helmholtz–Smoluchowski equation. It is shown that the predictions from the proposed fractal model are in good agreement with experimental data. In addition, the proposed model is able to reproduce the same result as the Helmholtz–Smoluchowski equation, particularly for high fluid conductivity or large grain diameters. Other factors influencing the streaming potential coefficient in porous media are also analysed.