Assessment of wind power potential for turbine installation in coastal areas of Turkey

This paper analyses the potential and the feasibility basis for the wind energy resources in some locations of coastal regions of Turkey. The dominant wind directions, the mean values, wind speeds, wind potential and the frequency distributions were determined. The results showed that Bal?kesir and Çanakkale among annual averages show higher value of mean wind speed. The mean annual value of Weibull shape parameter k is between 1.54 and 1.86 while the annual value of scale parameter c is between 2.52 m/s and 8.34 m/s. A technical assessment has been made of electricity generation from four wind turbines having capacity of 600 kW, 1500 kW, 2000 kW and 2500 kW. The yearly energy output and capacity factor for the four different turbines were calculated.     

Using MODIS snow cover maps in modeling snowmelt runoff process in the eastern part of Turkey

Water perhaps is the most valuable natural asset in the Middle East as it was a historical key for settlement and survival in Mesopotamia, “the land between two rivers”. At present, the Euphrates and Tigris are the two largest trans-boundary rivers in Western Asia where Turkey, Syria, Iran, Iraq and Saudi Arabia are the riparian countries. The Euphrates and Tigris basins are largely fed from snow precipitation whereby nearly two-thirds occur in winter and may remain in the form of snow for half of the year. The concentration of discharge mainly from snowmelt during spring and early summer months causes not only extensive flooding, inundating large areas, but also the loss of much needed water required for irrigation and power generation purposes during the summer season. Accordingly, modeling of snow-covered area in the mountainous regions of Eastern Turkey, as being one of the major headwaters of Euphrates-Tigris basin, has significant importance in order to forecast snowmelt discharge especially for energy production, flood control, irrigation and reservoir operation optimization.A pilot basin, located on the upper Euphrates River, is selected where five automated meteorological and snow stations are installed for real time operations. The daily snow cover maps obtained from Moderate Resolution Imaging Spectroradiometer MODIS at 500 m resolution are compared with ground information for the winter of 2002-2003 both during accumulation and ablation and at accumulation stage for the winter of 2003-2004. The snow presence on the ground is determined from the snow courses performed. Such measurements were made at 19 points in and around the upper Euphrates River in Turkey and at 20 points in the upper portion of the pilot basin for the winters of 2002-2003 and 2003-2004, respectively. Comparison of MODIS snow maps with in situ measurements over the snow season show good agreement with overall accuracies ranging between 62% and 82% considering the shift in the days of comparison. The main reasons to have disagreement between MODIS and in situ data are the high cloud cover frequency in the area and the current version of the MODIS cloud-mask that appears to frequently map edges of snow-covered areas and land surfaces. The effect of elevation and land cover types on validation of MODIS snow cover maps is also analyzed. In order to minimize the cloud cover and maximize the snow cover, MODIS-8 daily snow cover products are used in deriving the snow depletion curve, which is one of the input parameters of the snowmelt runoff model (SRM). The initial results of modeling process show that MODIS snow-covered area product can be used for simulation and also for forecasting of snowmelt runoff in basins of Turkey.     

Ester exchange reactions in polyarylate/poly(ethylene terephthalate) blends

Blends coagulated by a solution/precipitation procedure of a polyarylate (PAr) based on bisphenol A and tere/isophthalates with poly(ethylene terephthalate) (PET) have been studied by a variety of experimental methods. Differential scanning calorimetry experiments have shown that in blends containing more than 30% PET, conditioning of the blends at high temperatures required for calorimetric measurements resulted in progressive ester exchange reactions. The 10% and 20% PET mixtures, in which this extreme conditioning was not required, showed a single glass transition, contrary to the behaviour of the other PET compositions. These differences may be attributed to the shape of the spinodal curve, which has been simulated according to the McMaster model for polymer mixtures. The progression of the interchange reactions has been followed by solvent extraction of the resulting products and subsequent Fourier transform infra-red spectroscopy analysis. A parallel decrease in the PET heat and temperature of fusion in the insoluble fractions was observed. In our opinion this was due to the incorporation of PAr units in the PET chains, which caused a decrease in their crystallizable segment length.     

Mapping potential motorised sightseeing recreation supply across broad privately-owned landscapes of the Southern United States

The recreational opportunities available across landscapes of the Southern United States can be broad and diverse, and collectively are considered a subset of cultural ecosystem services. In describing the settings of recreational opportunities, a number of methods have been proposed that are based in part on geographic information and that can be facilitated by geographical analyses. Presented here are two expedient and cost-effective methods for assessing the recreation supply potential of large, heavily-roaded areas that are situated mainly with privately-owned land in the Southern United States. One land classification process uses fine-scale aerial imagery and other geospatial data in a process that results in three recreational opportunity setting zones with a focus on motorised sightseeing: foreground, background, and remote areas. Within these zones, land cover was derived and aggregated into three major land cover classes, including forest, agriculture, and bare ground classes. Further, a second process uses fuzzy classification methods, and through this highly suitable recreation settings were identified. Each recreational opportunity zone is further subdivided by public- and privately-owned land. We feel these types of recreation setting models can allow managers and planners to gain an understanding of the passive recreation potential of heavily-roaded privately-owned landscapes typical of the Southern United States.     

Strategic Management Practices in Turkish Construction Firms

This paper presents a study that aims to define the present position of Turkish construction companies in terms of strategic management. It is based on a survey measuring strengths and weaknesses in the “strategic management” practices of Turkish construction companies, and thus reveals potential opportunities and threats in a generalized manner. The results highlight the current strategic management practice of construction firms for designing their own future. Toward this aim, a detailed questionnaire was administered to 52 construction companies. The culture of companies and their perceptions of strategic management were shown to have serious shortcomings. However, specialization on different project types through joint venture companies established by their partners was found to be a major strength of many companies. These companies also pointed out the developing and unstable nature of both the political and economic structure of Turkey as their most significant threat. This disadvantage has inclined many firms to choose investment in the private sector as a response.     

Phase Equilibria for Ternary Liquid Systems of (Water + Carboxylic Acid + 1‐Heptanol) at 293.15 K: Modelling Considerations

Liquid‐liquid equilibrium data of the solubility curves and tie‐line end compositions are presented for mixtures of [water (1) + formic acid, or acetic acid, or propanoic acid (2) + 1‐heptanol (3)] at T = 293.15 K and P = (101.3 ± 0.7) kPa. The properties and liquid‐liquid equilibria (LLE) of associated ternary systems have been correlated using a solvatochromic approach SERLAS. The tie‐lines were also predicted using the UNIFAC‐original model. The proposed model appears to be an improvement in data fit for the ternary systems yielding a mean error of 3.8% for all the systems considered.     

Study of the pre-equilibrium mean free path constant for light and heavy nuclei for (n, xn) reactions

Using pre-equilibrium reaction mechanisms, the neutron-emission spectra produced by (n, xn) reactions for some target (A = 16 ∼ 238) nuclei have been calculated for incident neutron energy in the range of 15–26 MeV. From light nuclei to heavy nuclei, the multiple pre-equilibrium mean free path constants from internal transition have been investigated. The obtained results are discussed and compared with the available experimental data.     

Learning feature-projection based classifiers

This paper aims at designing better performing feature-projection based classification algorithms and presents two new such algorithms. These algorithms are batch supervised learning algorithms and represent induced classification knowledge as feature intervals. In both algorithms, each feature participates in the classification by giving real-valued votes to classes. The prediction for an unseen example is the class receiving the highest vote. The first algorithm, OFP.MC, learns on each feature pairwise disjoint intervals which minimize feature classification error. The second algorithm, GFP.MC, constructs feature intervals by greedily improving the feature classification error. The new algorithms are empirically evaluated on twenty datasets from the UCI repository and are compared with the existing feature-projection based classification algorithms (FIL.IF, VFI5, CFP, k-NNFP, and NBC). The experiments demonstrate that the OFP.MC algorithm outperforms other feature-projection based classification algorithms. The GFP.MC algorithm is slightly inferior to the OFP.MC algorithm, but, if it is used for datasets with large number of instances, then it reduces the space requirement of the OFP.MC algorithm. The new algorithms are insensitive to boundary noise unlike the other feature-projection based classification algorithms considered here.     

月桂酸纤维素酯的均相法合成

在纤维素LiCl/N,N-二甲基乙酰胺(DMAc)均相溶液体系中,以对甲苯磺酰氯(TosCl)为共反应剂,原位活化月桂酸,合成了月桂酸纤维素酯。采用红外光谱、核磁共振、热重等分析手段对产品进行了表征。考察了反应物配比、温度、时间等酯化条件对产品取代度的影响。结果表明:酯化产品的取代度与反应物纤维素葡萄糖苷、月桂酸和对甲苯磺酰氯的配比、反应温度及反应时间有关。在最佳酯化条件下,所得产品的取代度(DS)为2.58。热重分析结果表明,酯化反应削弱了纤维素分子间及分子内的作用力,赋予了月桂酸纤维素酯较好的热加工性。月桂酸纤维素酯在有机溶剂中的溶解度随取代度的增加而提高。     

Sulfidogenic biotreatment of synthetic acid mine drainage and sulfide oxidation in anaerobic baffled reactor

The treatment of synthetic acid mine drainage (AMD) water (pH 3.0-6.5) containing sulfate (3.0-3.5 g L(-1)) and various metals (Co, Cu, Fe, Mn, Ni, and Zn) was studied in an ethanol-fed sulfate-reducing 4-compartment anaerobic baffled reactor (ABR) at 32°C. The reactor was operated for 160 days at different chemical oxygen demand (COD)/sulfate ratios, hydraulic retention times (HRT), pH, and metal concentrations to study the robustness of the process. The last compartment of the reactor was aerated at different rates to study the bio-oxidation of sulfide to elemental sulfur. The highest sulfate reduction efficiency (88%) was obtained with a feed sulfate concentration of 3.5 g L(-1), COD/sulfate mass ratio of 0.737, feed pH of 3.0 and HRT of 2 days without aeration in the 4th compartment. The corresponding COD removal efficiency was about 92%. The alkalinity produced in the sulfidogenic ethanol oxidation neutralized the acidic mine water from pH 3.0-4.5 to pH 7.0-8.0. Effluent soluble and total heavy metal concentrations were substantially reduced with removal efficiencies generally higher than 99%, except for Mn (25-77%). Limited aeration in the 4th compartment of ABR promoted incomplete oxidation of sulfide to elemental sulfur rather than complete oxidation to sulfate. Depending on the aeration rate and HRT, 32-74% of produced sulfide was oxidized to elemental sulfur. This study demonstrates that by optimizing operating conditions, sulfate reduction, metal removal, alkalinity generation, and excess sulfide oxidation can be achieved in a single ABR treating AMD.