Methods for solving the nonlinear equilibrium equation of a compressed elastic rod

A nonlinear boundary value problem on the equilibrium of a compressed elastic rod on nonlinear foundation is considered for cases of free pinching or pivotally supported of the ends. The problem is written as a nonlinear operator equation. Numerical and analytical methods for solving nonlinear boundary value problems are discussed: The Newton-Kantorovich method and the Lyapunov-Schmidt method. We also consider a problem linearized on a trivial solution (the eigenvalue problem), which has an exact solution (Euler) in the case of a hinge support, and for the case of pinching the ends of the rod, the solution formulas are obtained in the works of A. A. Esipov and V. I. Yudovich. The eigenvalue problem is also solved by numerical method. To determine the equilibria of a nonlinear boundary value problem for a given value of the compressive force, it is proposed to apply the Newton-Kantorovich method in combination with the numerical methods, using as initial approximations the asymptotic formulas of new solutions found using the Lyapunov-Schmidt method in the vicinity of the critical value closest to the current value of the compressive load. Numerical calculations are performed and conclusions are drawn about the effectiveness of the methods used.

What improves smart meters' implementation? A statistical meta-analysis on smart meters' acceptance

PurposeThis article aims to compare smart meters' acceptance studies worldwide to consolidate trends and highlight factors that are not a consensus.Design/methodology/approachThis work performs a statistical meta-analysis, using the Hunter–Schmidt method and the UTAUT2 model, of the factors of acceptance of smart meters in the world literature. A meta-regression was also conducted to verify the moderation exercised by gender, level of education and timeline context of the articles.FindingsThe main results point to hedonic motivation, performance expectancy and effort expectancy as the leading influencers for smart meter's acceptance. Meta-regression indicates that the influence is more significant among the male gender and that over the years, the social influence must gain weight in the smart meter's acceptance.Social implicationsSpecific strategies are suggested to improve projects for the implementation of smart meters based on the obtained results.Originality/valueThe contribution given by this work is relevant, considering it is the first meta-analysis focused on smart meters' acceptance published in the literature

Synthesis and structural characterization of novel O-substituted phenolic and chalcone derivatives with antioxidant activity

A series of novel 4- O-alkyltriazolylphenolic derivatives is first synthesized with good to excellent yields via the click reaction of 3-methoxy-4- O-propargylbenzaldehyde or 3-allyl-4- O-propargylacetophenone and aromatic azide derivatives. Next, the chalcones are prepared via the Claisen-Schmidt method from 4- O-alkylphenylketone derivatives in the presence of the corresponding (hetero)aromatic aldehydes as electrophiles. The structures of the newly synthesized compounds are confirmed from their infrared, nuclear magnetic resonance spectral data, and by elemental analysis. The main advantages of this procedure are the simplicity of the reaction conditions, easily available starting materials, and simple work-up. The antioxidant activity of several of the products is determined using the DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) radical scavenging assay. 4- O-propargylvanillin (IC50 = 14.54 µg/mL) had moderate antioxidant activity.

BUCKLING A COMPRESSED ELASTIC RECTANGULAR PLATE WITH FREE EDGES

The influence of a small transverse load on the stability of an elastic rectangular plate compressed in one direction with free longitudinal edges, lying on a nonlinear elastic base, is studied. The plate contains internal stress sources in the form of continuously distributed edge dislocations and disclinations, or other sources, such as heat. The reaction of a nonlinear elastic base is taken into account in the form of a polynomial of the third degree of deflection. The compressive load is evenly distributed along the two opposite edges of the plate, which are freely pinched or pivotally supported. The other two edges of the plate are free. We consider a nonlinear boundary value problem for a modified system of nonlinear Karman equations that take into account internal stresses. By replacing variables, the problem is reduced to a sequence of two problems, of which the linear boundary value problem determines the function of stresses caused by the presence of internal sources, and the other, nonlinear, determines the deflection of the plate and the function of stresses caused by the compressive load. Using the Lyapunov-Schmidt method, the branching of solutions of a modified system of nonlinear Karman equations is investigated. The critical values of the load parameter are determined from a linearized problem based on a trivial solution. In this case, the variational method in combination with the finite-difference method is used to solve the linearized problem. The coefficients of the system of branching equations of the Lyapunov-Schmidt method are calculated numerically. The post-critical behavior of the plate is investigated and asymptotic formulas for new equilibria in the vicinity of critical loads are derived. For different parameter values of compressive loads and internal stresses the relations between the values of the parameters of the base, which preserve its load-bearing capacity in the vicinity of the classical critical load.

GA-MIMO: Genetic Algorithm for Optimization of ESPAR Antenna on Beamspace MIMO

<p><em>An electronically steerable passive array radiator (ESPAR) antenna can be used on a beamspace (BS)-multiple input multiple output (MIMO) system to reduce the device complexity. An ESPAR antenna has beamforming ability with single RF chain. However, antenna structure and channel conditions affect the number of orthogonal basis pattern which generated using Gram-Schmidt method. Based on this problem, reactance value at each parasitic element need to be optimized to form radiation pattern that required by the BS-MIMO. In this research, Genetic Algorithm (GA) is used to optimize reactance value which represented by the correlation between the desired and achieved radiation pattern, in different number of elements and different channel condition. GA is selected because this problem can be modeled as chromosome and several individual. Furthermore, the result shows in channel-ignorant and channel-aware, antenna with seven elements has a correlation in median value of 99.46% and 90.58%, respectively.</em></p><p><em> <em>Antena electronically steerable passive array radiator (ESPAR) dapat digunakan dalam sistem beamspace (BS)-multiple input multiple output (MIMO) dalam mengatasi kompleksitas perangkat. Antena ESPAR memiliki kemampuan untuk membentuk pola radiasi pada arah tertentu dengan menggunakan terminal tunggal, namun struktur antena dan kondisi kanal mempengaruhi pola dasar ortogonal yang dihasilkan melalui metode Gram Schmidt. Berdasarkan permasalahan tersebut, nilai reaktansi pada setiap elemen parasit perlu dioptimasi sehingga dapat menghasilkan pola radiasi yang dibutuhkan oleh sistem BS-MIMO. Pada penelitian ini, Algoritma Genetika digunakan untuk mengoptimasi nilai reaktansi yang direpresentasikan melalui korelasi antara pola radiasi yang dibutuhkan dengan pola radiasi yang dihasilkan, dalam jumlah elemen yang berbeda dan kondisi kanal yang berbeda. AG dipilih karena permasalahan ini dapat dimodelkan sebagai kromosom dan beberapa individual. Hasil analisis pada kondisi channel-ignorant dan channel-aware menunjukkan bahwa antena dengan tujuh elemen memiliki korelasi nilai median sebesar 99,46% dan 90,58%.</em></em></p>

A review on recent advances and potential pharmacological activities of versatile chalchone molecule

Chalchone is an aromatic ketone and precursors of open chain flavonoids and isoflavonoids present in edible plants and their derivatives have attracted attention due to many potential pharmacological activities. Chalchone are also known as benzalacetophenone and phenyl styryl ketone. Modifications in their structure have offered diverse pharmacological activities that have proven useful for the development of new medicinal agents having improved potency and lesser toxicity. They are also the intermediates in the Auwer's synthesis of flavanoids and in the biosynthesis of flavanoids. Chalchone can be synthesized by various method but the two main methods are Aldol condensation method and Claisen Schmidt method. This review provides an overview of the pharmacological activities of natural and synthetic chalchone derivatives.