Non-equilibrium physical systems approach to modeling evolution of optical fiber reliability

We propose a new approach, based on physics of non-equilibrium systems, to modeling optical fiber reliability. Unlike the traditional approach to statistical modeling of fracture, the presented one describes the phenomenon in terms of its dynamics and links the thermal-fluctuation damage events with the corresponding strength deterioration, thereby establishing an evolution equation of the time-dependent strength distribution. The developed model is validated by both simulations and experimental data.     

$$\varvec{\varphi }$$-admissibility results via extended simulation functions

We introduce the class of extended simulation functions, which is more large than the class of simulation functions, recently introduced in (Khojasteh et al. Filomat 29(6):1189–1194, 2015). We obtain a \(\varphi \)-admissibility result involving extended simulation functions, for a new class of mappings \(T: X\rightarrow X\), with respect to a lower semi-continuous function \(\varphi : X\rightarrow [0,\infty )\), where X is a set equipped with a certain metric d. The main theorem in this paper generalizes a recent \(\varphi \)-admissibility result obtained in (Karap?nar et al. Fixed Point Theory Appl 2015:152, 2015), and many other related results.     

HESI-MS/MS Analysis of Phenolic Compounds from Calendula aegyptiaca Fruits Extracts and Evaluation of Their Antioxidant Activities

Considering medicinal plants as an inexhaustible source of active ingredients that may be easily isolated using simple and inexpensive techniques, phytotherapy is becoming increasingly popular. Various experimental approaches and analytical methods have been used to demonstrate that the genus Calendula (Asteraceae) has a particular richness in active ingredients, especially phenolic compounds, which justifies the growing interest in scientific studies on this genus’ species. From a chemical and biological viewpoint, Calendula aegyptiaca is a little-studied plant. For the first time, high-performance liquid chromatography combined with negative electrospray ionization mass spectrometry (HPLC-HESI-MS) was used to analyze methanolic extracts of Calendula aegyptiaca (C. aegyptiaca) fruits. Thirty-five molecules were identified. Flavonoids (47.87%), phenolic acids (5.18%), and saponins (6.47%) formed the majority of these chemicals. Rutin, caffeic acid hexoside, and Soyasaponin βg’ were the most abundant molecules in the fruit methanolic extract, accounting for 17.49% of total flavonoids, 2.32 % of total phenolic acids, and 0.95% of total saponins, respectively. The antioxidant activity of the fruit extracts of C. aegyptiaca was investigated using FRAP, TAC, and DPPH as well as flavonoids and total phenols content. Because the phenolic components were more extractable using polar solvents, the antioxidant activity of the methanolic extract was found to be higher than that of the dichloromethane and hexane extracts. The IC50 value for DPPH of methanolic extract was found to be 0.041 mg·mL⁻¹. Our findings showed that C. aegyptiaca is an important source of physiologically active compounds.     

Degrees-Of-Freedom in Multi-Cloud Based Sectored Cellular Networks

This paper investigates the achievable per-user degrees-of-freedom (DoF) in multi-cloud based sectored hexagonal cellular networks (M-CRAN) at uplink. The network consists of N base stations (BS) and K≤N base band unit pools (BBUP), which function as independent cloud centers. The communication between BSs and BBUPs occurs by means of finite-capacity fronthaul links of capacities CF=μF·12log(1+P) with P denoting transmit power. In the system model, BBUPs have limited processing capacity CBBU=μBBU·12log(1+P). We propose two different achievability schemes based on dividing the network into non-interfering parallelogram and hexagonal clusters, respectively. The minimum number of users in a cluster is determined by the ratio of BBUPs to BSs, r=K/N. Both of the parallelogram and hexagonal schemes are based on practically implementable beamforming and adapt the way of forming clusters to the sectorization of the cells. Proposed coding schemes improve the sum-rate over naive approaches that ignore cell sectorization, both at finite signal-to-noise ratio (SNR) and in the high-SNR limit. We derive a lower bound on per-user DoF which is a function of μBBU, μF, and r. We show that cut-set bound are attained for several cases, the achievability gap between lower and cut-set bounds decreases with the inverse of BBUP-BS ratio 1r for μF≤2M irrespective of μBBU, and that per-user DoF achieved through hexagonal clustering can not exceed the per-user DoF of parallelogram clustering for any value of μBBU and r as long as μF≤2M. Since the achievability gap decreases with inverse of the BBUP-BS ratio for small and moderate fronthaul capacities, the cut-set bound is almost achieved even for small cluster sizes for this range of fronthaul capacities. For higher fronthaul capacities, the achievability gap is not always tight but decreases with processing capacity. However, the cut-set bound, e.g., at 5M6, can be achieved with a moderate clustering size.     

A study of fractional Lotka-Volterra population model using Haar wavelet and Adams-Bashforth-Moulton methods

The Lotka-Volterra (LV) system is an interesting mathematical model because of its significant and wide applications in biological sciences and ecology. A fractional LV model in the Caputo sense is investigated in this paper. Namely, we provide a comparative study of the considered model using Haar wavelet and Adams-Bashforth-Moulton methods. For the first method, the Haar wavelet operational matrix of the fractional order integration is derived and used to solve the fractional LV model. The main characteristic of the operational method is to convert the considered model into an algebraic equation which is easy to solve. To demonstrate the efficiency and accuracy of the proposed methods, some numerical tests are provided.     

Discrete Sturm comparison theorems on finite and infinite intervals

The Sturm comparison theorem for second-order Sturm–Liouville difference equations on infinite intervals is established and discussed.     

A numerical approach based on ln‐shifted Legendre polynomials for solving a fractional model of pollution

The model of pollution for a system of 3 lakes interconnected by channels is extended using Caputo‐Hadamard fractional derivatives of different orders α_i∈(0,1), i=1,2,3. A numerical approach based on ln‐shifted Legendre polynomials is proposed to solve the considered fractional model. No discretization is needed in our approach. Some numerical experiments are provided to illustrate the presented method.     

Poly(pyrrole‐co‐pyrrole‐2‐carboxylic acid)/Pyruvate Oxidase Based Biosensor for Phosphate: Determination of the Potential,and Application in Streams

A biosensor based on conductive poly(pyrrole‐co‐pyrrole‐2‐carboxylic acid) [Poly(Py‐co‐PyCOOH)] copolymer film coated gold electrode was developed for the quantitative phosphate determination. Enzyme pyruvate oxidase was immobilized chemically via the functional carboxylated groups of the copolymer. The potential to be applied which is deficiency of phosphate biosensor studies for precise phosphate detection was clarified by using differential pulse voltammetry technique. Performance of the sensing ability of the biosensor was improved by optimizing cofactor/cosubstrate concentrations, polymeric film density and pH. The biosensor showed a linearity up to phosphate concentration of 5 mM, operational stability with a relative standard deviation (RSD) of 0.07 % (n=7) and accuracy of 101 % at ?0.15 V (vs. Ag/AgCl). Detection limit (LOD) and sensitivity were calculated to be 13.3 μM and 5.4 μA mM^?1 cm^?2, respectively by preserving 50 % of its initial response at the end of 30 days. It's performance was tested to determine phosphate concentrations in two streams of Zonguldak City in Turkey. Accuracy of phosphate measurement in stream water was found to be 91 %.     

Synthesis of chiral chromenes from levoglucosenone

Levoglucosenone, an optically active α,β-unsaturated ketone available from cellulose, undergoes a stereoselective oxa-Michael-aldol domino reaction with 2-hydroxybenzaldehydes with the formation of optically active oxepino[4,5-b]chromen-1-ones. These compounds attacked by nucleophiles undergo recyclization to 4-substituted oxepino[3,4-b]chromen-11a-ols, while their oximes treated with SOCl₂ are converted to 3-cyano-2H-chromenes through the Beckmann fragmentation.