Açikel, S.; Cumhur, I.; Öztürk, A.; Başoğlu, M.; Düzgün, I.

This work systematically examines the influence of partial substitution of calcium (Ca) by erbium (Er) on the structural integrity and superconducting performance of Bi2Sr2Ca2Cu3O10+δ (BSCCO) high-temperature superconductors. Samples were synthesized through the conventional solid-state reaction method and characterized via X-ray diffraction, scanning electron microscopy, resistivity, and magnetization measurements. Despite the close effective ionic radii of Er and Ca, experimental results revealed that increasing Er content led to a deterioration of the superconducting phase and the emergence of semicon ducting characteristics. Quantitative analyses demonstrated a notable reduction in critical current density (Jc), with undoped BSCCO samples exhibiting approximately 14% higher Jc values under equivalent conditions. These findings suggest that while ionic size considerations may permit Er substitution from a stoichiometric perspective, the structural and superconducting phase stability of the BSCCO matrix is adversely affected by Er incorporation.

Caliskan, A.

We consider the production of excited electrons with spin-1/2 at future SPPC-based electron–proton colliders with center-of-mass energies of 8.4, 11.6, 26.6, and 36.8 TeV. These exotic particles are predicted in the composite models. We calculate the production cross sections and concentrate on the photon decay channel of the excited electrons with the process of ep → e*X → eγX. The pseudo rapidity and transverse momentum distributions of the electrons and photons in the final state have been plotted to determine the kinematical cutoffs best suited for discovery of the excited electrons. By applying these cutoffs we compute 2σ, 3σ, and 5σ contour plots of the statistical significance of the expected signal in the parameter space (L, m*), where L denotes the integrated luminosity of the collider and m* is the mass of the composite electrons.

Karabıdak, S.M.; Kaya, S.

Pile up and dead time are two important corrections in the analysis of X-ray and gamma ray spectra. The most important of these is pile up correction because these peaks do not really exist in the spectra; they only seem to exist. For this reason, these peaks affect both the qualitative and quantitative accuracy of the analysis. In addition, the pile up pulses forming the pile up peaks increase the background count in the spectrum. Companies that produce X-ray or gamma ray detector systems design pile up reject circuits and integrate them into detector systems to prevent these pulses. These circuits have time limitations because they are made up of electronic devices. For this reason, the pile up problem cannot be solved completely in these circuits. Therefore, mathematical models based on a statistical approach are needed. Such a model was developed in this study. A computer program based on this model was developed. This developed program has been applied to X-ray and gamma ray spectra. It has been shown that this model provides about 2% correction in the main peak regions and significantly reduces background counts.

Yildirim, Ahmet; Gökdoǧan, Ahmet; Merdan, Mehmet

In this article, the multi-step differential transform method is implemented to give approximate and analytical solutions of nonlinear fractional order ordinary differential equation systems, such as Chen, Lorenz, Arneodo-Coullet, Genesio, Lui, and Rikitake chaotic systems. The numerical solutions obtained from the proposed method indicate that the approach is easy, simple, and accurate when applied to systems of fractional differential equations. Numerical simulations are given to verify the reliability and effectiveness of this method.