Separation of Cd(II) from Aqueous Solutions by A New Consecutive Process Consisting of Supported Liquid Membrane and Electrodialysis

Altin, Sureyya,Altin, Ahmet The Korean Electrochemical Society 2019 Journal of electrochemical science and technology Vol.10 No.1

Supported liquid membrane process usually is used for recovering or enrichment of valuable metals in the industrial wastewater. But, even if the metals in the wastewater was separated with high chemical selectivity, it cannot be enough concentrated since separation performance of supported liquid membrane (SLM) process is limited by concentration gradient between feed solution and stripping solution. If metal concentration in the stripping solution to be enough low, transport of metal through membrane can be accomplishment constantly. Therefore, Electrodialysis (ED) has been placed after SLM process and the stripping solution of SLM was used as the feed solution for the ED process. Transport of ions in the solutions is successfully performed by ED process. Thus, the metal concentration in the stripping solution does not rise as to stop ion transport. Besides, valuable metals easily are concentrated by ED process for re-use. In this study, effects of operation parameters like initial Cd(II) concentration, HCl concentration in the feed solution of SLM and applied voltage are investigated on separation efficiency, flux and permeability of the both processes. As the feed solution concentration increased, all performance values has increased. When initial concentration of 100 mg/L is used, separation performances (SP) are 55% and 70%, for SLM and consecutive process, respectively. The best HCl concentration in the feed solution of SLM has determined as 2 M, in this conditions SP are 64% and 72%, for SLM and consecutive process, respectively. With increased of applied voltage on ED process, SP of the consecutive process has been raised from 72% to 83%. According to the obtained experimental data, consecutive process has better separation performance than SLM. When the separation performances of both processes were compared for the same operating conditions, it was determined higher the separation efficiency, permeability and flux values of the consecutive process, 8%, 9% and %10.6, respectively. Consequently, the use of the consecutive process increases the performance efficiency of both processes. The consecutive process studied has quite a good chemical separation efficiency, and enrichment capability. Moreover, this process requires few water and energy.

MgB2 thin film fabrication with excess Mg by sequential e-beam evaporation and transport properties under magnetic fields

E. Altin,F. Kurt,S. Altin,M.E. Yakinci,Z.D. Yakinci 한국물리학회 2014 Current Applied Physics Vol.14 No.3

Superconducting MgB2 thin films with different thicknesses were fabricated by excess Mg using sequential electron beam evaporation technique. The flux rate of Mg and B were chosen as 3 nm/sn and 0.5 nm/sn respectively. The thickness of Mg/B layer was determined as 3/1 which causes an excess Mg for MgB2 formation. After two-step preparation process, the superconducting transition temperatures were found in the range of 32e37 K with a sharp transition to zero resistance state. The irreversibility fields, upper critical fields and activation energies were derived from magneto resistivity curves. The transport critical current densities of films were determined from IeV characteristics under different applied fields and the data was extrapolated for determination of value of the 0 K.

Comparison of electrodialysis and reverse electrodialysis processes in the removal of Cu(II) from dilute solutions

Sureyya Altin,Elif Oztekin,Ahmet Altin 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.8

Electrodialysis (ED) and electrodialysis reversal (EDR) processes have been often used for separation of ions in dilute solutions. In this study, the performance of ED and EDR processes has been examined in the removal of copper from the dilute solutions. First, applied voltage, initial concentration, flow rate, type of electrolyte and the effect of concentration were determined for both processes. Then, separation efficiency, current efficiency, energy requirement and material flux of the processes were calculated, and the performances of the processes were compared. The separation efficiency and energy consumption of EDR process were higher compared to ED process under equal operating conditions. Also, the current efficiency (39.58%) of EDR process was lower than the current efficiency (67.46%) of ED process. It can be said that the ED process is more suitable in terms of energy consumption for separation in the low flow rate and concentration.

RULED SURFACES IN E³ WITH DENSITY

Altin, Mustafa,Kazan, Ahmet,Karadag, H.Bayram The Honam Mathematical Society 2019 호남수학학술지 Vol.41 No.4

In the present paper, we study curves in 𝔼³ with density $e^{ax^2+by^2}$, where a, b ∈ ℝ not all zero constants and give the parametric expressions of the curves with vanishing weighted curvature. Also, we create ruled surfaces whose base curves are the curve with vanishing weighted curvature and the ruling curves are Smarandache curves of this curve. Then, we give some characterizations about these ruled surfaces by obtaining the mean curvatures, Gaussian curvatures, distribution parameters and striction curves of them.

Rehabilitation of heavily earthquake damaged masonry building using steel straps

Altin, Sinan,Kuran, Fikret,Anil, Ozgur,Kara, M. Emin Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.30 No.6

The purpose of this study is to develop a rehabilitation technique for heavily earthquake damaged masonry buildings. A full scale one storey masonry building with window and door openings was manufactured and tested on the shock table by applying increased amplitude free vibration up to the point where heavy earthquake damage was observed. Damaged test building was rehabilitated with vertical and diagonal steel straps and then tested again. The effectiveness of improvements obtained by the rehabilitation technique was investigated. Steel straps improved the lateral strength and stiffness of masonry walls and limited the lateral displacement of building. Stability of the masonry walls were also improved by the steel straps. Steel straps reduced the natural period of the earthquake damaged masonry building and prevented the failure of the building at the same amplitude of free vibration.

A NOTE ON LACUNARY STATISTICALLY CONVERGENT DOUBLE SEQUENCES OF FUZZY NUMBERS

Altin, Yavuz Korean Mathematical Society 2008 대한수학회논문집 Vol.23 No.2

In this paper we introduce and study lacunary statistical convergence for double sequences of fuzzy numbers and we shall also present some inclusion theorems.

Rehabilitation of heavily earthquake damaged masonry building using steel straps

Sinan Altin,Fikret Kuran,Özgür Anil,M. Emin Kara 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.30 No.6

The purpose of this study is to develop a rehabilitation technique for heavily earthquake damaged masonry buildings. A full scale one storey masonry building with window and door openings was manufactured and tested on the shock table by applying increased amplitude free vibration up to the point where heavy earthquake damage was observed. Damaged test building was rehabilitated with vertical and diagonal steel straps and then tested again. The effectiveness of improvements obtained by the rehabilitation technique was investigated. Steel straps improved the lateral strength and stiffness of masonry walls and limited the lateral displacement of building. Stability of the masonry walls were also improved by the steel straps. Steel straps reduced the natural period of the earthquake damaged masonry building and prevented the failure of the building at the same amplitude of free vibration.

Ruled surfaces in $E^{3}$ with density

Mustafa Altin,Ahmet Kazan,H.Bayram Karadag 호남수학회 2019 호남수학학술지 Vol.41 No.4

In the present paper, we study curves in $\mathbb{E}^{3}$ with density $e^{ax^{2}+by^{2}},$ where $a,b\in \mathbb{R}$ not all zero constants and give the parametric expressions of the curves with vanishing weighted curvature. Also, we create ruled surfaces whose base curves are the curve with vanishing weighted curvature and the ruling curves are Smarandache curves of this curve. Then, we give some characterizations about these ruled surfaces by obtaining the mean curvatures, Gaussian curvatures, distribution parameters and striction curves of them.

RULED SURFACES IN E³ WITH DENSITY

( Mustafa Altin ),( Ahmet Kazan ),( H. Bayram Karadag ) 호남수학회 2019 호남수학학술지 Vol.41 No.4

In the present paper, we study curves in E³ with den- sity e^ax2+by2, where a, b ∈ R not all zero constants and give the parametric expressions of the curves with vanishing weighted cur- vature. Also, we create ruled surfaces whose base curves are the curve with vanishing weighted curvature and the ruling curves are Smarandache curves of this curve. Then, we give some characteriza- tions about these ruled surfaces by obtaining the mean curvatures, Gaussian curvatures, distribution parameters and striction curves of them.

Thermal conductivity and magnetic properties of the B substituted Ca3Co4O9

S. Altin,A. Bayri,S. Demirel,M.A. Aksan 한국물리학회 2014 Current Applied Physics Vol.14 No.4

In this study, we reported the effects of the boron (B) substitution into the Ca site in the Ca3Co4O9 system on the electrical, thermal and magnetic properties between 300 K and 5 K. The results indicated that the B-substitution into the system caused an increase of resistivity due to the decrease on carrier concentration. Thermal conductivity decreased for the x ¼ 0.5 B-substituted sample and then increased with increasing the B-content. Analysis on the thermal conductivity of samples showed that the phonon ephonon interaction term is the dominant component in the total thermal conductivity for all the samples. It was found that the point defect contribution to the thermal conductivity increased by increasing the B-content. The temperature dependence of magnetic susceptibility showed a paramagnetic behavior at room temperature and ferrimagnetic behavior below 20 K for unsubstituted sample. But, the magnetization decreased in the B-substituted samples. The substitution of B into the Ca site destroyed the interlayer coupling, which resulted in the decrease of the ferromagnetic behavior. The susceptibility data was fitted using CurieeWeiss law with temperature independent term and the meff values were calculated to be 1.42 mB and 3.89 mB for unsubstituted sample and the highest B-substitution, respectively.