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Purpose |!|#8211; Solving the non-linear equation f(x)=0 has nice applications in various branches of physics and engineering. Sometimes the applications of the numerical methods to solve non-linear equations depending on the second derivatives are restricted in physics and engineering. The purpose of this paper is to propose two new modified Newton|!|#39;s method for solving non-linear equations. Convergence results show that the order of convergence of the proposed iterative methods for a simple root is four. The iterative methods are free from second derivative and can be used for solving non-linear equations without computing the second derivative. Finally, several numerical examples are given to illustrate that proposed iterative algorithms are effective. Design/methodology/approach |!|#8211; In this paper, first the authors introduce two new approximations for the definite integral arising from Newton|!|#39;s theorem. Then by considering these approximations, two new iterative methods are provided with fourth-order convergence which can be used for solving non-linear equations without computing second derivatives. Findings |!|#8211; In this paper, the authors propose two new iterative methods without second derivatives for solving the non-linear equation f(x)=0. From numerical results, it is observed that the new methods are comparable with various iterative methods. Also numerical results corroborate the theoretical analysis. Originality/value |!|#8211; The best property of these schemes is that they are second derivative free. Also from numerical results, it is observed that the new methods are comparable with various iterative methods. The numerical results corroborate the theoretical analysis. [ABSTRACT FROM AUTHOR]

Purpose Realistic data bank of aerodynamic and stability derivatives is still missing for hybrid buoyant aerial vehicles. Such vehicles take-off and land similar to an aircraft with their partial weight balanced by the aerostatic lift. The purpose of this paper is to use wind tunnel testing for a better understanding of the aerodynamic and static stability behavior of such vehicles.Design/methodology/approach The effect of wing on the aerodynamic and static stability characteristics of a clean configuration hybrid buoyant is analyzed. The free stream velocity is 20 m/s, and ranges of angle of attack and side slip angle are from −8° to 12° and ±16°, respectively. Data are corrected to account for the effect of strut interference and zero load condition. The maximum blockage of the model with respect to the cross-section area of the test section is about 2.7 per cent.Findings A hybrid model manufactured by using wood and metal is an optimum solution with less number of parts. The vehicle is statically, longitudinally and directionally stable. Wings designed to fulfill the partial requirement of lift contribute significantly to counter the huge moment generated by the voluminous hull for centre of gravity location ahead of the leading edge of the wing.Research limitations/implications There are number of manufacturing constraints for scaling down a model of a hybrid buoyant aerial vehicle configuration. Specially, the thickness of the wing limits the testing envelop of angle of attack and free stream velocity.Practical implications The data presented here are a preliminary guide for further work on larger size models. The data may also be used to build and perform flight tests on small full-scale instrumented models and to obtain flight dynamics data.Originality/value The estimated aerodynamic and stability derivatives and slopes can be utilized in future for multidisciplinary design. [ABSTRACT FROM AUTHOR]

Purpose – Piezoelectric actuators (PEAs) exhibit hysteresis nonlinearity in open-loop operation, which may lead to unwanted inaccuracy and limit system performance. Classical Preisach model is widely used for representing hysteresis but it requires a large number of first-order reversal curves to ensure the model accuracy. All the curves may not be obtained due to the limitations of experimental conditions, and the detachment between the major and minor loops is not taken into account. The purpose of this paper is to propose a modified Preisach model that requires relatively few measurements and that describes the detachment, and then to implement the inverse of the modified model for compensation in PEAs. Design/methodology/approach – The classical Preisach model is modified by adding a derivative term in parallel. The derivative gain is adjusted to an appropriate value so that the measured and predicted hysteresis loops are in good agreement. Subsequently, the new inverse model is similarly implemented by adding another derivative term in parallel with the inverse classical Preisach model, and is then inserted in open-loop operation to compensate the hysteresis. Tracking control experiments are conducted to validate the compensation. Findings – The hysteresis in PEAs can be accurately and conveniently described by using the modified Preisach model. The experimental results prove that the hysteresis effect can be nearly completely compensated. Originality/value – The proposed modified Preisach model is an effective and convenient mean to characterize accurately the hysteresis. The compensation method by inserting the inverse modified Preisach model in open-loop operation is feasible in practice. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to develop a new protective coating formulation for industrial use, using benzodiazepine derivatives as double function additives. Design/methodology/approach: Benzodiazepine's derivatives of types (3–5) were prepared and confirmed by infrared, Mass, 1H-Proton nuclear magnetic resonance (NMR) and 13C NMR spectra. The synthesized compound was physically incorporated in the alkyd paint formulation by pebble mill grinding until all particulates are smaller than 20 ums. The prepared coatings were applied by air spray on steel panels. The physical, mechanical characteristics, corrosion resistance and antimicrobial test of the prepared coatings were studied to evaluate the prepared compounds drawbacks. Findings: The results of the mechanical and physical properties of the paint formulation revealed that the paint formulation incorporating benzodiazepines derivatives 3–5 performed best and improved corrosion-resistance and antibacterial activity tests. Research limitations/implications: In alkyd paint, heterocyclic compounds are the most used antibacterial additives. Other functionalities of these compounds, such as corrosion inhibitors, might be studied to see if they are suited for these applications. Practical implications: Because of the activity of various benzodiazepine derivatives, which may be attributable to the presence of some function groups such as sulfonamide aromatic amino NH2 group, and elements such as Sulphur, Nitrogen, Chlorine, in its chemical structure. As a result, paint compositions including these compounds as additives can be used as dual-purpose paint and for a variety of industrial applications. Originality/value: The research demonstrates how a low-cost paint composition based on synthesized benzodiazepine derivatives 3–5 may be used as a dual-function paint for industrial use. [ABSTRACT FROM AUTHOR]