Artificial neural network models for forecasting monthly precipitation in Jordan

Forecasting precipitation in arid and semi-arid regions, in Jordan in the Middle East for example, has particular importance since precipitation is the unique source of water in such regions. In this study, 1-month ahead precipitation forecasts are made using artificial neural network (ANN) models. Feed forward back propagation (FFBP), radial basis function (RBF) and generalized regression type ANNs are used and compared with a simple multiple linear regression (MLR) model. The models are tested on monthly total precipitation recorded at three meteorological stations (Baqura, Amman and Safawi) from different climatological regions in Jordan. For the three stations, it is found that the best calibrated model is FFBP with respect to all performance criteria used in the study, including determination coefficient, mean square error, mean absolute error, the slope and the intercept in the best-fit linear line of the scatter diagram. In the validation stage, FFBP is again the best model in Baqura and Amman. However, in Safawi, the driest station, not only FFBP but also RBF and MLR perform equally well depending on the performance criterion under consideration.     

Analysis of Diffusion and Adsorption of Volatile Organic Compounds in Zeolites by a Single Pellet Moment Technique

The diffusion and adsorption of two common volatile organic compounds, i. e., methanol and benzene, in different zeolite pellets were studied experimentally by using the single pellet moment technique. The experiments were conducted in a one‐sided single pellet adsorption cell at different temperatures in the range between 303 and 343 K. The results showed that both volatile organic tracers were adsorbed reversibly onto all zeolite samples. The overall adsorption equilibrium constants of both volatile organic compounds decreased with increasing temperature. The adsorption of the tracers onto the zeolite samples were found to increase in the order of NaY > clinoptilolite > 4A. In the range between 303 and 343 K, the adsorption constants of benzene range from 10.51 to 5.52 for zeolite 4A, from 11.90 to 6.37 for clinoptilolite and from 20.32 to 9.82 for NaY. The adsorption constants of methanol range from 19.05 to 8.26 for zeolite 4A, from 38.40 to 9.12 for clinoptilolite and from 74.21 to 14.70 for NaY at temperatures between 303 and 333 K. The effective diffusivities for benzene varied from 2.20·10^–6 to 13.01·10^–6 m²/s, whereas for methanol, they varied from 9.80·10^–6 to 15.60·10^–6 m²/s at the temperatures studied.     

Determination of Polycyclic Aromatic Hydrocarbons in Soil by Miniaturized Ultrasonic Extraction and Gas Chromatography‐Mass Selective Detection

A miniaturized ultrasonic extraction procedure was developed for the determination of polycyclic aromatic hydrocarbons (PAHs) in soil by gas chromatography‐mass spectrometry. After determination of the most suitable extraction solvent with 5 min sonication time, several other parameters (sample amount, solvent volume and number of extraction times) were optimized using a 2³ factorial experimental design. Recoveries of PAHs from spiked soil samples were over 90% for three different fortification levels between 50 and 300 μg/kg, and relative standard deviations of the recoveries were in the range of < 1–15%. The limits of detection ranged from 0.002 to 1.87 μg/kg. The performance of the developed procedure was also compared with other traditional Soxhlet, shake flask and large scale ultrasonic extraction procedures on real soil samples, and extraction methods showed comparable efficiencies. The proposed procedure required small volumes of solvent and sample. It was practicable, rapid and easy to use for analysis of PAHs in soils.     

Current velocity forecasting in straits with artificial neural networks,a case study: Strait of Istanbul

Owing to their complex character, modeling flow patterns of narrow straits has always been a challenge, even with the numerical techniques of today. This study was aimed at predicting vertical current profiles of a given point in a narrow strait, the Strait of Istanbul. On account of the speed and simplicity it offers, and of its remarkable success in solving complex problems, the feed forward back propagation (FFBP) artificial neural network (ANN) technique was chosen for this study. The model was built on 7039 hours of concurrent measurements of current profiles, meteorological conditions, and surface elevations. The model predicted 12 outputs of East and North velocity components at different depths in a given location. Various alternative models with different inputs and neuron numbers were evaluated attaining the best model by trial and error. Predictions from proposed ANN model were in accordance with the observations with average root mean square error of 0.16 m/s. The same input parameters were then used to build models that predicted current velocities 1–12 h into the future. Results of these predictions show good overall agreement with observations and that FFBP ANN can be used as a reliable tool for forecasting current profiles in straits.     

土耳其棉花堡与中国黄龙和白水台钙华退化原因对比研究

通过比较中国四川黄龙、中国云南白水台、土耳其帕穆克卡莱棉花堡三地钙华景观的基本环境地质特征、钙华景观水化学、钙华沉积生物因素的差异性,探讨了土耳其棉花堡钙华退化缓慢的影响因素。对比发现,棉花堡景区藻类约为38种,种类单一,植被覆盖率较低,沉积主要受物理化学因素控制,沉积速率较快,多形成较好的层状结构,杂质少,且原生孔隙度较低,结构致密,结晶度较高,不易坍塌损坏;黄龙和白水台景区藻类分别为86种、196种,种类多样,且植被覆盖率皆高达80%以上,沉积主控于化学和生物因素,沉积速率较慢,结构呈多孔疏松状或多孔珊瑚状,原生孔隙度普遍较高,易退化。此外,棉花堡钙华景区泉水各离子含量均高于黄龙和白水台景区,尤其是Ca2+和HCO3-,这能有效促进CaCO3的沉积。     

Systematic paleontology,biostratigraphy, paleobiogeography of <Emphasis Type="Italic">Loftusia</Emphasis> (foraminifera) and <Emphasis Type="Italic">Rudist</Emphasis> assemblages in a regressive sequence in the Hekimhan-Malatya area (Eastern Anatolia) Turkey

The Maastrichtian regressive sequence of the Hekimhan-Malatya area in Eastern Turkey consists of dolomitic limestones, limestones and calcareous mudstones which are dominated by rudists and Loftusia (foraminifera) assemblages. Several Loftusia species indicating middle to late Maastrichtian age such as Loftusia anatolica Meriç, L. baykali Meriç, L. coxi Henson, L. harrisoni Cox, L. minor Cox and L. morgani Douvillé have been recorded. Other benthic foraminifers present include Orbitoides medius d’ Archiac, Omphalocyclus macroporus (Lamarck), Laffitteina conica Drooger, Laffitteina mengaudi (Astre) and Laffitteina oeztuerki Inan. The rudists are abundant in the dolomitic limestones in the study area. The genus Miseia Patrulius is dominant and represented by Miseia bilacunosa Özer and Miseia hekimhanensis Karacabey-Öztemür. The Loftusia species and the Rudists assemblage indicates middle to late Maastrichtian age for the formation. The paleobiogeographic distribution of the assemblage has been discussed taking this find into account.     

Determination of sediment deposition of Hasanlar Dam using bathymetric and remote sensing studies

Natural Hazards - Hasanlar Dam and Hydroelectric Power Plant are located on Küçük Melen Creek in the Western Black Sea Basin of Turkey. The dam was constructed in 1974 to provide...     

The effect of opium poppy oil diesel fuel mixture on engine performance and emissions

Recently, decreasing of fossil fuel reserves and their negative effect on environment have increased the interest in alternative energy sources. One of the alternative energy sources is vegetable oils. In this study, blends of 50 % opium poppy oil — 50 % diesel fuel mixture are tested as alternative fuel on a single cylinder, 4-stroke, air cooled, pre-combustion chamber diesel engine at different speeds and its effects on engine performance and emissions are investigated. When compared to the diesel fuel as average, engine torque and power decrease at 4 % and 5.73 %, respectively. Specific fuel consumption increases by using of 50% opium poppy oil — 50 % diesel fuel mixture. When compared to the diesel fuel as average, carbon monoxide and nitrogen oxides emissions of 50 % opium poppy oil — 50 % diesel fuel mixture decrease to 15.5 % and 5.9 %, respectively. Diesel fuel-opium poppy oil mixture has been found notably successful and environment friendly as an alternative fuel for diesel engines.     

Experimental determination of three-dimensional dispersivities in homogeneous porous medium

Laboratory tracer experiments were conducted to investigate longitudinal dispersivity (α _x ) as well as the transversal (α _y ) and vertical (α _z ) dispersivities in homogeneous 3–5 mm sandy aquifer. The experiments were carried out in a channel 12-m long, 1.35-m wide and 0.60-m high which was built in the Hydraulics Laboratory of Civil Engineering Department in Dokuz Eylul University. NaCl was used as a tracer and conductivity values were measured at 220 measurement points. Mass Transport 3 Dimensional (Zheng and Wang in SERDP-99-1, US Army Engineer Research and Development Center, Vicksburg, MS, 1999; MT3DMS code) which is a three-dimensional solute transport simulation model incorporating finite differences solution option was used to solve the three-dimensional advective–dispersive transport equation. The estimated dispersivity values were modified until an acceptable compatibility between the observed and calculated concentrations at measurement points was reached. The best match was obtained for α _x  = 12 cm, α _y /α _x  = 0.2 and α _z /α _x  = 0.05. These values are compatible with those encountered in the literature.