Simulating deposition of high density tailings using smoothed particle hydrodynamics

Yagmur Babaoglu,Paul H. Simms 한국유변학회 2017 Korea-Australia rheology journal Vol.29 No.3

Tailings are a slurry of silt-sized residual material derived from the milling of rock. High density (HD) tailings are tailings that have been sufficiently dewatered to a point where they exhibit a yield stress upon deposition. They form gently sloped stacks on the surface when deposited; this eliminates or minimizes the need for dams or embankments for containment. Understanding the flow behaviour of high density tailings is essential for estimating the final stack geometry and overall slope angle. This paper focuses on modelling the flow behaviour of HD tailings using smoothed particle hydrodynamics (SPH) method incorporating a ‘bi-viscosity’ model to simulate the non-Newtonian behaviour. The model is validated by comparing the numerical results with bench scale experiments simulating single or multi-layer deposits in two-dimensions. The results indicate that the model agreed fairly well with the experimental work, excepting some repulsion of particles away from the bottom boundary closer to the toe of the deposits. Novel aspects of the work, compared to other simulation of Bingham fluids by SPH, are the simulation of multilayer deposits and the use of a stopping criteria to characterize the rest state.

New Approach to Pell and Pell-Lucas Sequences

Yagmur, Tulay Department of Mathematics 2019 Kyungpook mathematical journal Vol.59 No.1

In this paper, we first define generalizations of Pell and Pell-Lucas sequences by the recurrence relations $$p_n=2ap_{n-1}+(b-a^2)p_{n-2}\;and\;q_n=2aq_{n-1}+(b-a^2)q_{n-2}$$ with initial conditions $p_0=0$, $p_1=1$, and $p_0=2$, $p_1=2a$, respectively. We give generating functions and Binet's formulas for these sequences. Also, we obtain some identities of these sequences.

HARDY SPACE OF LOMMEL FUNCTIONS

Yagmur, Nihat Korean Mathematical Society 2015 대한수학회보 Vol.52 No.3

In this work we present some geometric properties (like star-likeness and convexity of order ${\alpha}$ and also close-to-convexity of order ($1+{\alpha}$)/2) for normalized of Lommel functions of the first kind. In order to prove our main results, we use the technique of differential subordinations and some inequalities. Furthermore, we present some applications of convexity involving Lommel functions associated with the Hardy space of analytic functions, i.e., we obtain conditions for the function $h_{{\mu},{\upsilon}}(z)$ to belong to the Hardy space $H^p$.

HARDY SPACE OF LOMMEL FUNCTIONS

Nihat Yagmur 대한수학회 2015 대한수학회보 Vol.52 No.3

In this work we present some geometric properties (like star- likeness and convexity of order α and also close-to-convexity of order (1 + α)/2) for normalized of Lommel functions of the first kind. In order to prove our main results, we use the technique of differential subordina- tions and some inequalities. Furthermore, we present some applications of convexity involving Lommel functions associated with the Hardy space of analytic functions, i.e., we obtain conditions for the function hμ,v(z) to belong to the Hardy space Hp.

Fekete-Szegö Problem for a Generalized Subclass of Analytic Functions

Orhan, Halit,Yagmur, Nihat,Caglar, Murat Department of Mathematics 2013 Kyungpook mathematical journal Vol.53 No.1

In this present work, the authors obtain Fekete-Szeg$\ddot{o}$ inequality for certain normalized analytic function $f(z)$ defined on the open unit disk for which $$\frac{{\lambda}{\beta}z^3(L(a,c)f(z))^{{\prime}{\prime}{\prime}}+(2{\lambda}{\beta}+{\lambda}-{\beta})z^2(L(a,c)f(z))^{{\prime}{\prime}}+z(L(a,c)f(z))^{{\prime}}}{{\lambda}{\beta}z^2(L(a,c)f(z))^{{\prime}{\prime}}+({\lambda}-{\beta})z(L(a,c)f(z))^{\prime}+(1-{\lambda}+{\beta})(L(a,c)f(z))}\;(0{\leq}{\beta}{\leq}{\lambda}{\leq}1)$$ lies in a region starlike with respect to 1 and is symmetric with respect to the real axis. Also certain applications of the main result for a class of functions defined by Hadamard product (or convolution) are given. As a special case of this result, Fekete-Szeg$\ddot{o}$ inequality for a class of functions defined through fractional derivatives are obtained.

Design of buckling restrained braces with composite technique

Ramazan Ozcelik,Yagmur Dikiciasik,Kazim B. Civelek,Elif F. Erdil,Ferhat Erdal 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.35 No.5

This paper focus on the buckling restrained braces (BRBs) with new casing members (CMs). Seven BRBs with CMs consisting of precast concrete modules (PCMs) were tested to investigate the effects of CMs on the cyclic performance of BRBs. The PCMs consisted of plain and reinforced concrete casted into wooden or steel molds than they were located on the core plate (CP) via bolts. There were 14 or 18 PCMs on the CP for each BRBs. The technique of the PCMs for the CM provides that the BRBs can be constructed inside the steel or reinforced concrete (RC) structures. In this way, their applications may be rapid and practical during the application of the retrofitting. The test results indicated that the cyclic performance of the BRBs was dominated by the connection strength and confinement of the PCMs. The BRBs with PCMs wrapped with fiber reinforced polymers (FRPs) sustained stable hysteretic performance up to a CP strain of 2.0 %. This indicates that the new designed BRBs with PCMs were found to be acceptable in terms of cyclic performance. Furthermore, the connection details, isolation materials and their application techniques have been also investigated for the improved BRB design in this study.

Weakly Nonergodic Dynamics in the Gross-Pitaevskii Lattice

Mithun, Thudiyangal,Kati, Yagmur,Danieli, Carlo,Flach, Sergej American Physical Society 2018 Physical review letters Vol.120 No.18

<P>The microcanonical Gross-Pitaevskii (also known as the semiclassical Bose-Hubbard) lattice model dynamics is characterized by a pair of energy and norm densities. The grand canonical Gibbs distribution fails to describe a part of the density space, due to the boundedness of its kinetic energy spectrum. We define Poincare equilibrium manifolds and compute the statistics of microcanonical excursion times off them. The tails of the distribution functions quantify the proximity of the many-body dynamics to a weakly nonergodic phase, which occurs when the average excursion time is infinite. We find that a crossover to weakly nonergodic dynamics takes place inside the non-Gibbs phase, being unnoticed by the largest Lyapunov exponent. In the ergodic part of the non-Gibbs phase, the Gibbs distribution should be replaced by an unknown modified one. We relate our findings to the corresponding integrable limit, close to which the actions are interacting through a short range coupling network.</P>

Dynamical Glass and Ergodization Times in Classical Josephson Junction Chains

Mithun, Thudiyangal,Danieli, Carlo,Kati, Yagmur,Flach, Sergej American Physical Society 2019 Physical review letters Vol.122 No.5

Bilateral Comparison of Mass Standards Between the UME (Turkey) and the KRISS (Korea)

이성준,정진완,김광표,Sevda Kacmaz,Levent Yagmur,Lenara Kangi 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.2

A bilateral comparison of mass standards of 100 mg, 100 g and 2 kg was carried out between the Ulusal Metroloji Enstitusu (UME, Turkey) and the Korea Research Institute of Standards and Science (KRISS, Korea) during the period from December 2005 to June 2006. For 100 g and 2 kg, the difference between the data obtained at the UME and those obtained at the KRISS was less than the combined uncertainty for the two standards. This result demonstrates accordingly, the metrological equivalence between the UME and the KRISS in dierent regions. Showing instability, 100 mg weight showed a degree of equivalence is larger than one. Despite this point, the measurement capability can still be validated because each uncertainty was within less than one-third the maximum permissible error (∽1.6 μg) for an E1 class weight.

Can the Mean Platelet Volume Be a Risk Factor for Vasculogenic Erectile Dysfunction?

Halil Ciftci,ErcanYeni,Mehmet Demir,Ismail Yagmur,Kemal Gümüş,Hakim Celik,Murat Savas,Mehmet Gulum 대한남성과학회 2013 The World Journal of Men's Health Vol.31 No.3

Purpose: The mean platelet volume (MPV) is a marker of the platelet activity and is reported to increase in vascular diseases. We aimed to investigate the association between MPV and vasculogenic erectile dysfunction (ED). Materials and Methods: MPV and platelet (PLT) levels were measured in 50 cases of ED and 40 healthy controls. The diagnosis of vasculogenic ED was based on a detailed sexual history, physical examination, laboratory assessment, and color Doppler ultrasonography. The results are given as mean±standard deviation of the mean. Results: The mean ages of the patient and the control groups were 53.70±12.39 years (range 24∼77 years) and 53.85±9.5 years (range 30∼73 years), respectively (p=0.947). The MPV and PLT values were significantly higher in the patients with ED than those of the controls (7.49±1.4), (6.85±1.2), (262.97±68), (252.89±82) respectively, p<0.001). However, the MPV values were not statistically significantly different in the patients with severe ED according to the International Index of Erectile Function than in those with mild ED, p>0.05), and there was no correlation between MPV and either age of patients (p=0.905) or duration of ED (p=0.583). Conclusions: The platelet count and MPV was detected to be increased in patients with vasculogenic ED. This finding suggests a role for platelets in the pathogenesis of vascular complications and that the MPV would be useful in monitoring disease progression.