Early mandibular canine-lateral incisor transposition: case report

Purpose. The main aim of the present study is to present a case of mandibular transposition between lateral incisor and canine in a paediatric patient. Materials and methods. A fixed multibracket orthodontic treatment was performed by means of a modified welded arch as to correct the transposition and obtaining a class I functional and symmetrical occlusion, also thanks to the early diagnosis of the eruption anomaly. Results. Our case report shows that a satisfactory treatment of mandibular transpositions is obtained when detected at an early stage of the tooth development. Conclusions. The main treatment options to be taken into consideration in case of a mandibular transposition are two: correcting the transposition or aligning it leaving the dental elements in their transposed order; in both cases, the followups show a stable condition, maintained without relapses. Several factors, such as age of the patient, occlusion, aesthetics, patient’s collaboration, periodontal support and duration of treatment have to be considered as to prevent potential damage to dental elements and support appliances. The choice between the two treatment approaches for mandibular lateral incisor/canine transpositions mainly depends on the time the anomaly is detected

Two-to-one resonant multi-modal dynamics of horizontal/inclined cables. Part I : theoretical formulation and model validation

This paper is first of the two papers dealingwith analytical investigation of resonant multimodal dynamics due to 2:1 internal resonances in the finite-amplitude free vibrations of horizontal/inclined cables. Part I deals with theoretical formulation and validation of the general cable model. Approximate nonlinear partial differential equations of 3-D coupled motion of small sagged cables - which account for both spatio-temporal variation of nonlinear dynamic tension and system asymmetry due to inclined sagged configurations - are presented. A multidimensional Galerkin expansion of the solution ofnonplanar/planar motion is performed, yielding a complete set of system quadratic/cubic coefficients. With the aim of parametrically studying the behavior of horizontal/inclined cables in Part II [25], a second-order asymptotic analysis under planar 2:1 resonance is accomplished by the method of multiple scales. On accounting for higher-order effectsof quadratic/cubic nonlinearities, approximate closed form solutions of nonlinear amplitudes, frequencies and dynamic configurations of resonant nonlinear normal modes reveal the dependence of cable response on resonant/nonresonant modal contributions. Depending on simplifying kinematic modeling and assigned system parameters, approximate horizontal/inclined cable models are thoroughly validated by numerically evaluating statics and non-planar/planar linear/non-linear dynamics against those of the exact model. Moreover, the modal coupling role and contribution of system longitudinal dynamics are discussed for horizontal cables, showing some meaningful effects due to kinematic condensation

Copper chloro-complexes concentrated solutions: An electrochemical study

Basic studies on concentrated solutions are becoming more and more important due to the practical industrial and geological applications. The use in redox flow batteries is one of the most important applications of these solutions. Specifically, in this paper we investigated high-concentrated copper chloro-complexes solutions with different additives. The concentration of ligands and additives affects the physicochemical and electrochemical properties of 2 M solutions of Cu(I) and Cu(II). Solutions with calcium chloride and HCl as Cl- source were investigated with Cu:Cl ratios of 1:5 and 1:7, the 1:5 Cu:Cl ratio being the best performing. The substitution of calcium chloride with ammonium chloride increased the conductivity. However, while the effect on the positive electrode process was not very evident, the reversibility of the copper deposition-stripping process was greatly improved. Orthophosphoric acid could be a viable additive to decrease the complexation of calcium with chloride anions and to improve the stability of Cu(II) chloro-complexes. Absorption spectroscopy demonstrated that phosphate ions do not coordinate copper(II) but lead to a shift in the distribution of copper chloro-complexes toward more coordinated species. Electrochemically, the increased availability of chloride anions in solution stabilized the Cu(II)-rich solution and led to increased reversibility of the Cu(II)/Cu(I) redox process

Periodic and Nonperiodic Responses of Shape-Memory Oscillators

Nonlinear responses of shape-memory oscillators are investigated systematically using a numerical procedure and a modified Ivshin-Pence model for the restoring force. Due to the discontinuities in the tangent stiffness, classical gradient-based shooting techniques for determining periodic responses are not applicable. Herein the implemented algorithm searches the periodic solutions as fixed points of the Poincar´e map. The Jacobian of the map is calculated via a central finite-difference scheme and its eigenvalues are computed to ascertain the stability of the solutions and the associated codimension-one bifurcations. A number of frequency-response curves are constructed for some meaningful shape-memory oscillators (characterized by different hysteresis loops) and for various excitation levels in the primary and superharmonic frequency ranges. The investigations are conducted both in isothermal and non-isothermal conditions. A rich class of solutions and bifurcations - including jump phenomena, pitchfork, period doubling, complete or incomplete bubble structures with a variety of nonperiodic responses - is found and discussed

Investigation of the buckling behaviour of composite laminated plates

The buckling behaviour of rectangular laminated composite plates is investigated employing a global higher-order theory. The displacement field is expanded in the thickness direction in a complete polynomial series with arbitrary degree whereas the series coefficients, function of the in-plane coordinates, are expressed, according to Ritz's method, as a superposition of admissible functions. The elastic and geometric stiffness matrices are obtained from the energy functionals in terms of the generalized coordinates. The problem is suitably nondimensionalized so as to single out the independent parameters. The convergence properties of the adopted discretization scheme are investigated first considering simply supported orthotropic three-layer composite plates under a transverse distributed load. Variations of the lowest buckling loads with the width-to-thickness ratio and with the ratio between the in-plane elastic moduli are also investigated to ascertain the sensitivity of the buckling behaviour with respect to these parameters. Static deflection and linear buckling analysis results are compared with exact 3D elasticity solutions, other laminated plate theories and 3D FE analyses

Storage and damping optimization in hysteretic multilayer nanocomposites

Optimization of the storage modulus and the hysteretic damping capacity of multilayer carbon nanotube (CNT) nanocomposites is carried out via a differential evolution algorithm coupled with a nonlinear finite element implementation of a 3D mesoscale theory of nanocomposites exhibiting CNT/polymer stick-slip behavior. Such constitutive theory describes the hysteresis due to the shear stick-slip between the carbon nanotubes and the long molecular chains of the hosting matrix wrapped around them. The storage modulus and the amount of energy dissipated through the CNT-matrix stick-slip depend on the nanocomposite microstructural parameters, such as the elastic mismatch, the nanofiller content, its distribution, and the CNT-matrix interfacial shear strength. The optimization problem seeks to determine the set of material parameters of a multilayer stacking sequence that can give rise to the largest storage modulus and damping capacity of the ensuing nanocomposite. The results confirm that the genetic-type multilayer nanocomposite damping optimization resorting on a sound mechanical model of the nonlinear hysteretic material response can be an effective and affordable design method