Anisotropic Zeeman Splitting in YbNi4P2

The electronic structure of heavy-fermion materials is highly renormalised at low temperatures with localised moments contributing to the electronic excitation spectrum via the Kondo effect. Thus, heavy-fermion materials are very susceptible to Lifshitz transitions due to the small effective Fermi energy arising on parts of the renormalised Fermi surface. Here, we study Lifshitz transitions that have been discovered in YbNi4P2 in high magnetic fields. We measure the angular dependence of the critical fields necessary to induce a number of Lifshitz transitions and find it to follow a simple Zeeman-shift model with anisotropic g-factor. This highlights the coherent nature of the heavy quasiparticles forming a renormalised Fermi surface. We extract information on the orientation of the Fermi surface parts giving rise to the Lifshitz transitions and we determine the anisotropy of the effective g-factor to be $\eta \approx 3.8$ in good agreement with the crystal field scheme of YbNi4P2.Comment: 10 pages, 5 figures, prepared for resubmission to SciPos

Solving an Optimal Control Problem of Cancer Treatment by Artificial Neural Networks

Cancer is an uncontrollable growth of abnormal cells in any tissue of the body. Many researchers have focused on machine learning and artificial intelligence (AI) based on approaches for cancer treatment. Dissimilar to traditional methods, these approaches are efficient and are able to find the optimal solutions of cancer chemotherapy problems. In this paper, a system of ordinary differential equations (ODEs) with the state variables of immune cells, tumor cells, healthy cells and drug concentration is proposed to anticipate the tumor growth and to show their interactions in the body. Then, an artificial neural network (ANN) is applied to solve the ODEs system through minimizing the error function and modifying the parameters consisting of weights and biases. The mean square errors (MSEs) between the analytical and ANN results corresponding to four state variables are 1.54e-06, 6.43e-07, 6.61e-06, and 3.99e-07, respectively. These results show the good performance and efficiency of the proposed method. Moreover, the optimal dose of chemotherapy drug and the amount of drug needed to continue the treatment process are achieved

A Numerical Approach for Solving Optimal Control Problems Using the Boubaker Polynomials Expansion Scheme

In this paper, we present a computational method for solving optimal control problems and the controlled Duffing oscillator. This method is based on state parametrization. In fact, the state variable is approximated by Boubaker polynomials with unknown coefficients. The equation of motion, performance index and boundary conditions are converted into some algebraic equations. Thus, an optimal control problem converts to a optimization problem, which can then be solved easily. By this method, the numerical value of the performance index is obtained. Also, the control and state variables can be approximated as functions of time. Convergence of the algorithms is proved. Numerical results are given for several test examples to demonstrate the applicability and efficiency of the method

Microbial biodegradable potato starch based low density polyethylene

Plastic materials remain in the nature for decades. Slow degradation of plastics in the environment caused a public trend to biodegradable polymers. The aim of this research was to produce the microbial biodegradable low density polyethylene with potato starch. Degradation of potato starch based low density polyethylene (LDPE) was investigated in soil rich in microorganisms for 8 months. Weight differences of polymeric samples before and after degradation in soil indicated soil biodegradation. Fourier transform spectroscopy (FTIR) approved the result. Scanning electron microscope (SEM) and weight change after 84 days’ exposure to Pseudomonas aeruginosa confirmed degradation by microorganisms. In addition, potato starch based LDPE was exposed to 8 different kinds of fungi and the degradation was studied visually. Result confirmed the microbialbiodegradability of potato starch based LDPE blend in natural and laboratory condition

Effect of the selected physico-chemical parameters on growth of rainbow trout (Oncorhynchus mykiss) in raceway system in Iran

A study was conducted to evaluate the correlation between selected physico-chemical parameters of water and their effects on growth of Rainbow trout (Oncorhynchus mykiss) in raceway system in the area of Sarab Gerdu, Iran. The samples were collected from twenty raceways (270-day old fish, surface area 55m^2 flow rate 150 ls^-1 total production 15 T). Physico-chemical parameters were the fluctuations of total ammonia nitrogen, dissolved oxygen, turbidity, nitrogen (nitrates), phosphorous (phosphates), total dissolved solids, electrical conductivity, fluoride, boron, pH, temperature, total hardness, and alkalinity. Multivariate analyses were conducted employing three categories of parameters including A, B, and C. The results of the study showed that temperature and pH variations were similar. Dissolved oxygen with negative similarity coefficient, _0.618 was located in the third category while positive coefficient, 0.479 of other parameters except for pH and temperature (second category) and dissolved oxygen (third category) was located in the first one. pH value was not in a standard range due to increase in water temperature. This, in turn had impact on other parameters, such as unionized ammonia, a toxic chemical, to fish. Our result demonstrated that nitrate concentration is the most significant chemical parameter for fish growth in this area. Similarity, increase in concentration of dissolved oxygen in the water (from 3.30 mgl^-1 up to 12 mgl^-1) was necessary to promote productivity

Optimization of energy consumption of ozone generator and plasma generator in decolorization and disinfecting of water system in urban residence

BACKGROUND AND OBJECTIVES: The water field futurology is mostly focused on the water shortage and resulting political-security crises. However, the emphasis of this study is on the water pollution crisis. This study utilizes water decolorization and microbial decontamination as novel and low-risk methods in water and water resources sanitization with the preservation of the municipal environment approach. Modern oxidation methods for pre-treatment or aid-treatment have well-attained their place in the water and wastewater treatment process to reduce microbial and chemical contamination of water. Applying light, plasma, ozone, and Ultraviolet light is one of the modern and eco-friendly methods for water treatment and disinfection with growing usage.METHODS: In this research, various types of ozone and plasma generators, with the approach of energy consumption reduction, were manufactured for simultaneous decolorization and disinfecting of the water. All these devices consist of three main sections; frequency-increasing circuits, voltage-increasing transformers, and a reactor based on electrical discharge in gas. The simulation was performed using Orcad and PSPICE and Comsol softwares. After designing and simulation, a pilot of each of these three sections was made.FINDINGS: Both plasma and ozone reactors, which act as light tubes with a purple color spectrum were made and optimized for water treatment in the form of tubular tubes and flat cell for volume and surface radiation. Microbial testing of 8 water samples in terms of coliform in laboratory was confirmed by the Iran Environmental Organization mpn/100ml.RESULTS: After computer simulation, all three basic sections of an ozone generator device with a power consumption equal to a 30-watt lightbulb were made and optimized. By 5-minute injection of the ozone generated by this device into the water containing methylene blue as the color contamination index and Escherichia coli as the microbial contamination index, 99% of microbial decontamination was achieved, along with decolorization.CONCLUSION: Various types of plasma devices for decolorization and disinfecting water were made in this research. Due to the light-like nature of the plasma treatment and since the tested water sample was volumetric, and above all, due to the turbidity of the tested water sample, 30 minute of plasma treatment had no comparable effect to the ozonation method. Therefore, generating and injecting ozone was still the most effective method for simultaneous decolorization and microbial decontamination. The discoloration of water samples by ozonation with optimized devices was noticeable in the first minute

Cascade of magnetic field induced Lifshitz transitions in the ferromagnetic Kondo lattice material YbNi4P2

A ferromagnetic quantum critical point is thought not to exist in two and three-dimensional metallic systems yet is realized in the Kondo lattice compound YbNi4(P,As)2, possibly due to its one-dimensionality. It is crucial to investigate the dimensionality of the Fermi surface of YbNi4P2 experimentally but common probes such as ARPES and quantum oscillation measurements are lacking. Here, we studied the magnetic field dependence of transport and thermodynamic properties of YbNi4P2. The Kondo effect is continuously suppressed and additionally we identify nine Lifshitz transitions between 0.4 and 18 T. We analyze the transport coefficients in detail and identify the type of Lifshitz transitions as neck or void type to gain information on the Fermi surface of YbNi4P2. The large number of Lifshitz transitions observed within this small energy window is unprecedented and results from the particular flat renormalized band structure with strong 4f-electron character shaped by the Kondo lattice effect.Comment: 6 pages, 4 figure