2018 Cilt 23 Sayı 2

Permanent URI for this collectionhttps://hdl.handle.net/11452/12466

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Atmospheric organochlorinated pesticide levels and gas/particle partitioning in Istanbul during winter weather conditions
(Uludağ Üniversitesi, 2018-05-28) Kuzu, S. Levent
In this study, gas and particle phase ambient organochlorine pesticide (OCP) levels were investigated atan urban site in Istanbul. Samples were collected by a high-volume sampler for fourteen days in winter. Individual OCP concentrations were between13 and 593 pg.m-3 for particle phase and 14 and 1,748 pg.m-3 for gaseous phase. The sums of the average concentration of each OCP in gaseous and particle phases were 3,219 and 2,746 pg.m-3 , respectively. δ-HCH had the highest individual concentration. The abundance of DDTs followed the order 4.4'-DDT > 4.4'-DDD > 4.4'-DDE.The Σ(gas+particle)OCP concentrations ranged between 1,845 and 10,196 pg.m-3 . On the days when high concentrations were observed, the trajectories of air masses were investigated by the HYSPLIT model. logKp versus logPL 0 model was applied in order to determine the fate of gas/particle partitioning. The average slope of the regression line was -0.35, whereas the intercept was -2.89.
Centralized versus decentralized wastewater reuse: A case study for a touristic area
(Uludağ Üniversitesi, 2018-07-11) Hocaoğlu, Selda Murat; Erzi, İpek; Ergenekon, Seyla
In this study, centralized and decentralized wastewater reuse alternatives were compared in terms of water saving potential and costs for a touristic case study area in Antalya, Turkey. The results of decentralized reuse revealed that the maximum water saving of a hotel is limited with either amount of wastewater generated or ratio of irrigated landscape area to bed number. The breakpoint for the case study area is estimated as 50 m2 /bed. As a result, in hotels where the ratio of irrigated area is less than 50 m 2 /bed, wastewater reuse may not be cost effective. In case of centralized wastewater reuse, supply and demand is balanced and as a result 60% more water saving may be achieved for the case study area. Furthermore, investment and operation cost of centralized reuse are considerably low and the price of reclaimed water is lower than price of service water. The average unit price of reclaimed water used as irrigation water was found to be 1.29 €/m3 in decentralized reuse, while the unit price was found to be 0.35 €/m3 in centralized reuse; which brings forth an internal rate of return by 20% and a 5-year payback period.
The combined impact of SRS and FWM phenomena on the downlink channel performance of DWDM-GPON systems
(Uludağ Üniversitesi, 2018-05-23) Ibrahim, Faisal Ibrahim Mohamed; Karlık, Sait Eser; Mühendislik Fakültesi; Elektrik Elektronik Mühendisliği Bölümü
In this paper the combined impact of stimulated Raman scattering (SRS) and four-wave mixing (FWM) on the downlink channel performance of dense wavelength division multiplexed-gigabit passive optical networks (DWDM-GPONs) has been compared with the single impact of FWM via signal-tocrosstalk ratio (SXR) simulations performed on center downlink channels of 7-, 15- and 31-channel DWDM-GPON systems. Simulation results show that SRS compensates negative impacts of FWM and compensation significance enhances with increasing channel numbers and channel spacing values. At high channel spacing values of 50 GHz and 100 GHz, variation of SXR can display a strong oscillatory behavior in very short channel length variations of 0.5 km. The combined impact of SRS and FWM enhances the maximum oscillation amplitude of SXR variation with respect to the single impact of FWM at those channel spacing values. It has been observed that Raman gain exhibits an approximately linear variation with channel input powers in 0.1-5 mW range and it increases with increasing fiber lengths, channel spacing values and channel numbers. Results of this research emphasize the significant difference between the combined impact of SRS and FWM and the single impact of FWM on DWDM-GPON systems and give important hints for current DWDM-GPON implementations.
Determination of the efficiency of waste gas washing equipments used in jewelery workshop
(Uludağ Üniversitesi, 2018-07-06) Avşar, Edip; Hanedar, Asude; Alp, Kadir; Toröz, İsmail
During the processes where acid and cyanide are used in jewelery workshops, waste gases originates that hazardous in terms of human and environmental health and material. It is necessary to control these originated gas flows with suitable methods and equipment in the workshop and convert them to non-hazardous forms. For this purpose, waste gas washing equipment which can be used by various producers in jewelery workshops are produced. In this study, waste gas stream hazardous emissions removal efficiency of a system produced for this purpose was examined and the measures to be taken for the continuous efficiency were mentioned. According to results; it has been determined that the nitric acid emissions and the sulfuric acid emissions originated from the iron / copper solvation process are reduced by 94.5% and 88.3%, respectively, by means of waste gas washing system. It has been determined that cyanide emissions are reduced by 98.7% by washing the waste gases from the bombing process by means of washing system. According to results, treated toxic gaseous emission concentrations were below the limit. values of Turkish Industrial Air Pollution Control Regulation (TIAPCR) and Netherlands Emission Guidelines for Air (NER).
Effect of attack angle on flow around a square prısm wıth a splıtter plate
(Uludağ Üniversitesi, 2018-06-22) Seyhan, Mehmet; Sarıoğlu, Mustafa; Akansu, Yahya Erkan
Lift and drag forces on a square prism with a (splitter) plate are experimentally investigated by force measurements with a load cell. Results showed that drag and lift coefficients are independent of Reynolds number for Re = 9700 – 36500 at 0°, 45°, 90°, 135° and 180°. Drag coefficient at 0 is obtained as 2.02 for the square prism alone, and 1.04 for the square cylinder with splitter plate. Maximum drag reduction for the square cylinder with the plate is 50% as compared to the square cylinder at 0° and 15°. For α < 30° and α > 114°, drag coefficient of a square prism with splitter plate is smaller than that of the square prism alone. At Re = 20000, lift and drag coefficients significantly change with increasing attack angle.
Effects of elastic supports on nonlinear vibrations of a slightly curved beam
(Uludağ Üniversitesi, 2018-07-02) Sarıgül, Murat
In this study, nonlinear vibrations of a slightly curved beam having arbitrary rising function are handled. The beam is restricted in longitudinal direction using elastic supports on both ends. Sag-to-span ratio of the beam, which is assumed to have sinusoidal curvature function at the beginning, is taken as 1/10. Beam being of Euler-Bernoulli type rests on Winkler elastic foundation and carries an arbitrarily placed concentrated mass. Equations of motion are obtained by using Hamilton Principle. Cubic and quadratic nonlinear terms have been aroused at the mathematical model because of the foundation and the beam's elongation. The Method of Multiple Scales (MMS), a perturbation technique, is used to solve the equations of motion analytically. The primary resonance case is taken into account during steady-state vibrations. The natural frequencies are obtained exactly for different control parameters such as supports' types, locations of the masses and linear coefficient of foundation. Frequency-amplitude and frequencyresponse graphs are drawn by using amplitude-phase modulation equations.
Loss preventıon of fuel terminal operatıons: A case study in Turkey
(Uludağ Üniversitesi, 2018-08-27) Denizhan, Berrin; Görmez, İbrahim
Upon exiting the refinery, fuel products are distributed to vessels, from vessels to the terminals conducting the activities of fuel storage and distribution operations, and from terminals to stations via road tanker. Problems of loss in the product quantities occur after the movements of displacement of the product in terminal tanks and simultaneous the movements during filling operations. In this paper all operation processes of one of the fuel oil terminal in Turkey. The fuel products were received upon the unloading of the vessel and storage and distribution activities were carried out in this terminal. The elements causing loss during the terminal operation processes were examined with the failure modes and effects analysis (FMEA) technique. According to this analysis, the fields for which measures would be taken with precedence and a solution approach were presented for the company. While this approach is providing the causes of occurrence of failures as well as the control of loss for the company, the risk of fire and spillage likely to occur can be prevented as well.
A new message processing mechanism for internet of things
(Uludağ Üniversitesi, 2018-05-15) Toğay, Cengiz; Mühendislik Fakültesi; Bilgisayar Mühendisliği Bölümü
Data is the most valuable thing in Industry 4.0 Era. Devices in the industry produce a tremendous amount of data and they are stored or processed by the services. Because of the advantages of the cloud computing, now the data is on the Internet instead of the local servers. Therefore, thanks to the cloud computing, the data can be processed by third parties. There are two concerns about sharing the data; namely performance and privacy. For near real-time problems, the data should be sent to services as soon as possible. For privacy, only required and allowed part of the data payload should be shared among parties.Therefore, a processing mechanism is needed before sending the data to target nodes. In this study, a new mechanism is proposed for processing/filtering the data based on the target node needs and rules defined by the administrator.
A novel survey on solvent based-dyes containing shellac and pumice
(Uludağ Üniversitesi, 2018-05-25) Acaralı, Nil
This study aimed the dyes as decorative usage and improving the physical properties by using solvent based-dye with additives to evaluate in construction and chemical applications. The physical tests as viscosity, hydrophobicity, drying time, gloss effect, hiding power/transparency were applied on surfaces. Taguchi Method was used as an optimization method and characterization of molecular bonds was investigated with FT-IR. Shellac was used for protection of metallic surfaces and pumice increased the adhesive effect of dye. The test results showed that the additives did not affect the glossiness, color availability and drying time as a negative result. When the prepared dyes compared reference dyes, it was seen that hydrophobicity and hiding power/transparency effects were increased. FT-IR spectra showed that the prepared dyes had similar bonds with reference dyes.
Stability analysis of a class of Takagi-Sugeno Fuzzy Cohen-Grossberg neural networks with time delays
(Uludağ Üniversitesi, 2018-05-15) Özcan, Neyir; Barış, Samet; Fen Bilimleri Enstitüsü; Elektrik Elektronik Mühendisliği Bölümü
This paper deals with the problem of the global asymptotic stability of the class of TakagiSugeno Fuzzy Cohen-Grossberg neural networks with multiple time delays. By constructing a suitable fuzzy Lyapunov functional, we present a new delay-independent sufficient condition for the global asymptotic stability of the equilibrium point for delayed Takagi-Sugeno Fuzzy Cohen-Grossberg neural networks with respect to the Lipschitz activation functions. The obtained condition simply relies on the network parameters of the neural system. Therefore, the equilibrium and stability properties of the neural network model considered in this paper can be easily verified by exploiting some basic properties of some certain classes of matrices.
Streamflow and sediment load prediction using linear genetic programming
(Uludağ Üniversitesi, 2018-07-17) Mehr, Ali Danandeh; Şorman, Ali Ünal
Daily flow and suspended sediment discharge are two major hydrological variables that affect rivers’ morphology and ecosystem, particularly during flood events. Artificial neural networks (ANNs) have been successfully used to model and predict these variables in recent studies. However, these are implicit and cannot be simply used in practice. In this paper, linear genetic programming (LGP) approach has been suggested to develop explicit models to predict these variables in two rivers in Iran. The explicit relationships (prediction rules) evolved by LGP take the form of equations or program codes, which can be checked for its physical consistency. The results showed that the LGP outperforms ANNs to get global maximum and minimum discharges providing lowest root mean squared error and higher coefficient of efficiency both for training and validation periods.

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