In general, the outgoing exhaust gasses are released to atmosphere at over temperature of the dew point of water vapor in waste gases. It is well known that recovering a portion of the waste heat enhances the efficiency of boilers and provides fuel savings. In this study, the potential of recovering waste heat emitted by the hot water boiler chimney in a central heating plant of the selected university was investigated. Energy losses were calculated for six months that the central heating system was in full-load operation. As a result of the calculation, it was determined that recovery of the waste heat can be employed as a combustion air preheater by means of a recuperator. It was stated that 53768 m 3 of natural gas savings per year (44.86 TOE/year) can be achieved with the suggested system.
This study is carried out to assess the relative efficiencies of the Anatolian high schools in Izmir /Turkey and to guide inefficient educational institutions to become efficient. Firstly, efficiency measurement is performed by data envelopment analysis (DEA) model. Instead of assigning equal weights to the input and output variables, the analysis is repeated by assigning weights with the aid of the analytic hierarchy process(AHP) model. 3 input and 3 output variables are determined in the study and 47 Anatolian High Schools are analyzed. In Izmir, this study is important since it is the first study to assess the efficiencies of Anatolian high schools with data envelopment analytic hierarchy process (DEAHP) integrated model.
Simultaneous Localization and Mapping (SLAM) problem is a very popular research area in robotic applications. EKF-SLAM and FastSLAM are widely used algorithms for SLAM problem. The greatest advantage of FastSLAM over EKF-SLAM is that it reduces the quadratic complexity of EKF-SLAM. On the other hand, increasing number of estimated landmarks naturally slows down the operation of FastSLAM. In this paper, we propose a new method called as Intelligent Data Association-SLAM (IDA-SLAM) which reduces this slowing down problem. In data association step also known as likelihood estimation, IDA-SLAM skips comparing a new landmark with all of the pre-calculated landmarks. Instead of this, it compares the newly found one with only nearby landmarks that was found previously. The simulation results indicate that the proposed algorithm significantly speeds up the operation of SLAM without a loss of state estimation accuracy. Real world experiments which have been performed in two different scenarios verify the simulation results. A runtime reduction of 43% and 52% is observed respectively for each of the test environments.
3D printed polymer composites are gaining more interest due to weight reduction and high geometrical complexity freedom especially for highly demanding applications such as aerospace and defense.Using the material-extrusion based processes, polymer matrix composite parts with complex geometries can be designed and realized to improve the mechanical properties of pure thermoplastic parts.However, in addition to porosity found at the fracture interfaces, the layered nature additive manufacturing processes may become a limitation for the direct replacement for functional applications.In this study, the results of Charpy impact testing of chopped carbon fiber reinforced nylon fabricated by fused filament fabrication (FFF) are reported.The effects of the build direction and customized density by different infill strategies on the obtained toughness are presented in comparison to the one of nylon without any reinforcement.The toughness results show a severe anisotropy in toughness and high dependence on the infill strategy.
Under repeated loads, stress-strain and strength properties of soils play an important role in solving the engineering problems.The resistance of a material is defined by the slope of the initial part of stress-strain curve.However, this value changes due to cyclic loading and decreases cycle by cycle.As a result, deformations occur on the ground and resulting structural damage.Engineering properties of soils (such as modulus and damping properties of soil, shear wave velocity, unit weight etc..) must be known to minimize the effects of earthquakes.Another important parameter is the frequency content of earthquakes which directly affects the wave propagation through the soil.In this study, the effects of frequencies, obtained from different earthquakes, on the dynamic characteristics of the soil have been investigated.A dynamic triaxial test set has been used to examine the dynamic properties of soils.The variation of dynamic properties of sand samples under the experimental conditions has been determined for regular and irregular loading types.
This study is inspired by the work of Neumann in 2011.In the study, we establish some double inequalities involving the ratio, where is the -analogue of Euler's gamma function.Some monotonicity results involving k-gamma function are found.By the aid of these results, some inequalities such asfor > 0, 1 ≤ ≤ , where = 1 + 2 + ⋯ + are valid.
In this study, it was investigated the treatability of real wastewater from textile industry by electrochemical treatment methods (electrocoagulation and electrooxidation).Effect of important operating parameters such as, electrode type and combination (Al-Al, Fe-Fe, Al-Fe, Fe-Al, Pt-Fe), pH, reaction time and potential were investigated on removal efficiency of color and chemical oxygen demand (COD).The initial color and COD concentrations of the wastewater were 395 Pt-Co and 1040 mg/L, respectively.At the end of the electrocoagulation experiments, concentrations of color and COD were decreased to 28 Pt-Co and 115 mg/L, respectively.Results showed that at pH 3 and 6 V potential, up to 93% color and 89% COD removal efficiencies were obtained in the reactor consisting of Fe-Fe electrodes.COD and color were removed at the rate of 88% and 92%, respectively in the study done with Al-Al couple at 10 V in natural pH (6.96).COD removal was achieved in the ratio of 93% at 6V as a result of the electrooxidation study with a couple of Pt-Fe electrodes.The study showed that the removal process was promising and it was reached to the discharge limit values for the color and COD with each electrode couple specified in the regulation.When considering the removal efficiencies, electrocoagulation process is the best treatment method is for this study.In terms of energy consumption, the electrooxidation process is more economical to effectively remove COD
The propagation of harmonic waves in an elastic tube filled with fluid is presented in this study.The tube material is considered to be incompressible, homogeneous, isotropic, initially axially stretched, inflated, and constructed of thick elastic, like human arteries.The viscous fluid is assumed to be incompressible and Newtonian.The differential equations of both materials are obtained in cylindrical coordinates.The analytical solutions of the equations of motion for the fluid and numerical solutions of the equations of motion for the tube have been found.The residual circumferential strain in the unloaded state of artery causes an opening angle.The dispersion relation is presented as a function of the axial stretch, opening angle, internal pressure, and material parameters.The effects of these parameters are shown and discussed in the graphics.
In this study machinibility of hardox steel plates (welded by plasma and Mag welding) was examined in WEDM.Two different ampere values and two different feed rates were determined for the two different welding types.Depending on these factors ,micro structures, micro hardnesses and resistivity/conductivity values (varying according to heat output) were obtained at the HAZ and WM zones.Then, each of the samples taken from both HAZ and WM zones were cut in the WEDM by using 2 levelled four different parameters.The purpose at this stage is to examine the cutting width (kerf) and surface roughness (Ra) values at the HAZ and WM zones with respect to varying micro structure, micro hardness and conductivity values.At the end of the study, the lowest kerf was obtained with the plasma welded samples whereas the lowest Ra values were obtained with the Mag welded samples .The samples at WM zone are in general are the ones welded by high conductivity sample Mag welding.Whereas in the HAZ zone the samples are the ones welded by high conductivity plasma welding.
Time series prediction is a method to predict the system behavior in the future based on current given data.Neural Networks (NNs) approach is a well-known technique that is useful for time series prediction.In the literature many NN models such as Multilayer Perceptron (MLP), Pi-Sigma NN (PSNN), Recurrent NN etc. are proposed for solving time series prediction.In this paper, we use Multiplicative Neuron Model (MNM) to predict time series.For training this model, we propose to use newly developed evolutionary optimization algorithm called Sine Cosine algorithm (SCA), and this algorithm has not been used as far as we know in training the MNM.The proposed SCA-MNM model is employed for the well-known time series problems.In this paper, the application of the SCA-MNM on time prediction is illustrated using two mostly used datasets Mackey-Glass time series dataset, Box-Jenkins gas furnace dataset.To investigate the effect of the proposed SCA-MNM model, comparisons are made with some of the results given in the literature.
Natural Rubber (NR) has been used in dynamic applications for many years.NR has satisfactory resilience, vibration, and fatigue properties.Besides all these good properties, NR has quite poor aging resistance; also its service temperature is limited to about 90 °C.Improving aging characteristics of NR is a common problem for both rubber industry and academy.Nowadays, especially automotive industry has been focused on thermally resistant static and dynamic rubber based materials in new generation automobiles because of current strict emission regulations.There are a lot of attempts to improve service conditions of NR however; they are not comparable yet, with alternative saturated rubbers such as ethylene propylene diene monomer rubber (EPDM).In this study, a new grade EPDM, which had a high molecular weight, narrow molecular weight distribution, and tailor-made chain structure, has been studied in terms of rheological, mechanical, dynamic mechanical, aging, and low temperature properties for target dynamic applications.Especially possible service temperature and dynamic performance of EPDM were compared to that of NR based reference.It was concluded that, EPDM may be an assertive competitor to NR, if its chain structure is modified correctly.
Renewable energy resources have great potential to give solution to the long-lasting energy deficiency problems being faced by Pakistan.The aim of this study was to make use of multi criteria analysis for the identification of wind potential sites in KPK, Pakistan by utilizing the monthly 10 years (1983-1993) and 22 years (1983-2005) annual average wind speed data sets for the six districts (Chitral, Peshawar, Dir, DIK, Buner and Mansehra) at 10m and 50m, 100m, 150m, 300m altitudes, Earth Skin Temperature ( 0 C) and Atmospheric Pressure (kpa) respectively.At 10 m altitude, annual wind speed analysis showed similar pattern among all the districts, each with two maximum peaks one in April and the other between October and November.Multi-criteria Approach involved, creating suitable criteria for selected variables then classification (based on each variable magnitude), scores were then assigned to each class.Based on methodology (MCA) applied in this research, Chitral district appeared as the best location for exploiting in terms of wind power.
In this paper, the effects of hydrostatic pressure on the thermodynamic and vibrational properties such as bulk modulus, second order elastic constants, acoustic phonon frequencies, density of state (DOS) and Grüneisen parameters (γ) on Cu-%20Pd alloys was examined by using the molecular dynamics (MD) simulation.Interaction forces between atoms in the model system were calculated by Quantum Sutton-Chen (Q-SC) potential energy function.The simulation results obtained from this study were compared with the experimental and theoretical results in the literature.
Sustainable development depends on the availability of energy resources and their impact on environment.Biogas is a carbon neutral renewable energy option and one of the leading solutions to the climate change combat.As Turkey is an energy importer country, using indigenous energy sources is vital to meet future energy demand.Agricultural activities and livestock potential have high contribution to economy in Turkey.Biogas production from organic wastes such as livestock manure in this context, gain more importance to contribute both renewable energy production and waste management strategies.Livestock farming has important economic value in Burdur.In this regard, the animal manure based biogas potential, energy value, electricity and organic fertilizer generation capacity of Burdur Province were determined in this study.The results revealed that Burdur has annually 1.45 million tons of available animal manure potential to be used for biogas production of 27.1 million m 3 /year.This potential corresponds to 135.4 GWh annual energy generation that could be converted to heat and electricity.Considerable amount of the biogas production capacity has accumulated in the Center and, Bucak, Yeşilova, Gölhisar and Karamanlı districts of Burdur.In addition, about 50776 tons/year of organic fertilizer can be produced as the residual of the biogas plants.
This paper were investigated spectroscopic studies of 1-(4-Chlorophenyl) piperazine (14CPP) with nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) and Raman techniques. The conformational analysis, vibrational spectra, vibrational assignments and nuclear magnetic shielding tensors of title molecule were examined by the density functional theory (DFT), using the Becke-3-Lee-Yang-Parr (B3LYP) functional and the 6-311++G(d,p) basis sets. Moreover, energy gap values (HOMO-LUMO) of title molecule was performed using TD-DFT/B3LYP/6-311++G(d,p) method. There is a good agreement between the experimentally obtained data and theoretically obtained data.
In present study, Ag-doped TiO 2 bioceramic coatings were fabricated on cp-Ti by plasma electrolytic oxidation (PEO) and physical vapor deposition (PVD). The phase composition, surface microstructure, elemental composition, surface topography, wettability and chemical state of the PEO and Ag-doped TiO 2 surfaces were characterized by using powder- and thin film-X-ray diffraction (TF-XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), surface profilometer and contact angle measurement system (CAM), respectively. The PEO coating’ surface was porous and rough due to the nature of process. The Ti, anatase-TiO 2 , rutile-TiO 2 and Ag 2 O phases were detected on the Ag-doped PEO surfaces by TF-XRD while The Ti, anatase and rutile phases were obtained on the PEO surfaces. The surface morphology structure of the PEO coating was not changed by PVD process. The Ti, O, P and Ag elements were observed on the Ag-doped PEO surfaces by EDS. Also, the amount of Ag existed on the surface was below cytotoxic limit. The Ag-doped PEO surfaces indicated better hydrophilic character to the PEO surface owing to increasing polarity of the surfaces. In vitro hydroxyapatite-forming ability was evaluated by immersion in simulated body fluid (SBF) at 36.5 ° C for 28 days. The Ag-doped PEO surfaces showed good hydroxyapatite formation ability compared to the PEO surface. The antibacterial activity was evaluated by exposing the samples to Staphylococcus aureus ( S. aureus ) and Escherichia coli ( E. coli ) and they were compared by the reaction of the pathogens to Ag-doped PEO with the PEO controls. The antibacterial ability of the Ag-doped PEO surfaces was significantly improved respect to the PEO surfaces for S. aureus and E. coli .
A time domain performance criterion based on the multi-objective Pareto front solutions is proposed to tune the Proportional-Integral-Derivative (PID) controller parameters with the Cuckoo Search (CS) algorithm for different process systems: first order plus dead time (FOPDT) and high order dynamics. The proposed multi-objective cost function consists of conflicting objective functions including the overshoot, rise time, settling time and steady state error. In this paper, multi-objective genetic algorithm (MOGA) is used for obtaining the Pareto optimal solutions of the conflicting objective functions. The weights in the proposed multi-objective cost function are calculated by way of nondominated solutions of the obtained Pareto fronts based on the four conflicting objective functions. Also, the optimal tuning parameters of the PID controller are obtained by minimizing the integral based objective functions commonly introduced in the literature using the CS algorithm. The obtained results show that the CS optimized approach based on the proposed objective cost function outperforms than that of the integral based objective functions with higher efficiency and better quality no matter whether the process systems are employed under unload or load conditions.
Refractive index (RI) is one of the optical parameters that is of paramount interest in characterizing liquid solutions and solvents.Increased public awareness and legal requirements for quality standards in different sectors have created a need for reliable, fast, automated, remote and/or portable refractive index sensors with multi-measurement capability.The fiber-based RI sensors are very good candidates in providing attractive solutions in such application areas and have been attracting a growing interest by the scientific community.In this work, a fiber optic refractive index sensor has been investigated.It uses a long-period fiber grating (LPFG) and an Optical Spectrum Analyzer (OSA), as sensor head and interrogator unit, respectively.New measurements of refractive indices of common solvents and solutions at the low-loss telecom wavelength band have been successfully demonstrated by using the proposed sensor.The reported measurement results are in excellent agreement with our simulation results and reference measurements realized by conventional measurement techniques.
The longitudinal stability of an aircraft is analyzed using root locations of the transfer function's denominator (the characteristic equation).This transfer function is obtained by linearizing aircraft dynamic model at a certain operation point (altitude and speed).However, aircraft have varying stability derivatives, therefore dynamic behavior, for different flight phases such as takeoff, cruise, and landing.Thus the stability analysis of the characteristic equation can be said to be valid only for a single flight condition.In fact, stability derivatives vary with flight conditions, so an analysis that includes all possible stability derivatives in the flight envelope is required to guarantee stability.In this study, the two most variable stability derivatives in the transfer function were taken as uncertain parameters.Gridding these two parameters to check the stability of the unmanned aerial vehicle for all possible flight conditions is a possible method, but it is very time-consuming, and it cannot assure the stability theoretically.A new simple approach is developed by using the Edge and Bialas theorems, which guarantees stability despite the uncertainty of two stability derivatives.The problem is reduced to the analysis of four polynomials.With the eigenvalues of just four polynomials, the stability characteristics of an airplane for a given flight envelope can be easily determined.
Coprime array geometries provide robust performance for direction-of-arrival estimation problem with more sources than sensor elements. In previous works it is shown that K source directions can be resolved using only 2M + N -1 sensor elements where K is less than or equal to MN. In this paper we introduce a new approach to enhance the degrees of freedom (DOF) from MN to 2MN by using the same number of sensor elements. The proposed method is based on computing the covariance matrix of the observation data multiple times. Hence more DOF can be obtained. The resulting cross terms corresponding to the coherent sources are modeled as an interference in a sparse recovery algorithm which is solved effectively by an alternating minimization procedure. The theoretical analysis of the proposed method is provided and its superior performance is evaluated through numerical simulations.
