Similitude Principle Research Articles

Flow Field Research on an M-Beam Separator

The paper focuses on the resistance characteristic of a novel M-beam separator. Adopting the combination of experiment study and numerical simulation, we achieve that 2D simulation has the similar results as 3D in predicting resistance characteristic which provides the theoretical basis for next research. An M-beam separator model ten times larger than original one based on similitude principle was made for sake of flow field visualization research. The paper analyses flow field distribution of the amplifying M-beam separator by silk thread display technology and the experiment results are well consistent with 2D numerical simulation. The flow field distribution described here could serve as a reference for developing M-beam separator.

Dislocation and twin substructure evolution during strain hardening of an Fe–22 wt.% Mn–0.6 wt.% C TWIP steel observed by electron channeling contrast imaging

We study the kinetics of the substructure evolution and its correspondence to the strain hardening evolution of an Fe–22wt.% Mn–0.6wt.% C TWIP steel during tensile deformation by means of electron channeling contrast imaging (ECCI) combined with electron backscatter diffraction (EBSD). The contribution of twin and dislocation substructures to strain hardening is evaluated in terms of a dislocation mean free path approach involving several microstructure parameters, such as the characteristic average twin spacing and the dislocation substructure size. The analysis reveals that at the early stages of deformation (strain below 0.1 true strain) the dislocation substructure provides a high strain hardening rate with hardening coefficients of about G/40 (G is the shear modulus). At intermediate strains (below 0.3 true strain), the dislocation mean free path refinement due to deformation twinning results in a high strain rate with a hardening coefficient of about G/30. Finally, at high strains (above 0.4 true strain), the limited further refinement of the dislocation and twin substructures reduces the capability for trapping more dislocations inside the microstructure and, hence, the strain hardening decreases. Grains forming dislocation cells develop a self-organized and dynamically refined dislocation cell structure which follows the similitude principle but with a smaller similitude constant than that found in medium to high stacking fault energy alloys. We attribute this difference to the influence of the stacking fault energy on the mechanism of cell formation.

Statins withdrawal, vascular complications, rebound effect and similitude

Hahnemann considered the secondary action of medicines to be a law of nature and reviewed the conditions under which it occurs. It is closely related to the rebound effects observed with many modern drugs. I review the evidence of the rebound effect of statins that support the similitude principle. In view of their indications in primary and secondary prevention of cardiovascular diseases, statins are widely prescribed. Besides reducing cholesterol biosynthesis, they provide vasculoprotective effects (pleiotropic effects), including improvement of endothelial function, increased nitric oxide bioavailability, antioxidant properties, inhibition of inflammatory and thrombogenic responses, stabilisation of atherosclerotic plaques, and others. Recent studies suggest that suspension of statin treatment leads to a rebound imparing of vascular function, and increasing morbidity and mortality in patients with vascular diseases. Similarly to other classes of modern palliative drugs, this rebound effect is the same as a secondary action or vital reaction described by Samuel Hahnemann, and used in homeopathy in a therapeutic sense.

Brief Homeopathic Pathogenetic Experimentation: A Unique Educational Tool in Brazil

In homeopathy, many difficulties are encountered in understanding theoretical presuppositions because they represent different paradigms from those of hegemonic science. In our medical school, we developed a brief homeopathic pathogenetic experimentation course to be added as curricular content and a didactic method in homeopathic disciplines to add practical experience to the theoretical approach of homeopathic presuppositions. In accordance with the premises laid out by Hahnemann, the father of homeopathy, brief pathogenetic experimentation was offered on a voluntary basis for students who were free of chronic diseases and who had not regularly used medication in the last 3 months. The clinical test, either crossed or sequential (randomized and blind), was used as a study model. Single weekly doses of a homeopathic medicine of 30 cH or placebo were taken by participants during 4 weeks after which crossover of the experimented substances took place for another 4 weeks. Polycrest medicines were used so that symptoms developed by the participants could be compared to those described in Homeopathic Materia Medica. Thirty-three of the 50 students who studied homeopathy as an elective discipline over the last 4 years at the School of Medicine of the University of São Paulo (FMUSP) participated. Participants described symptoms according to specific methodology including many comments with peculiar characteristics and notable idiosyncrasies. All these students endorsed the course because it contributed to their understanding of how dynamized substances produced symptoms in healthy participants as well as the cure of symptoms according to the casual similitude principle. Brief homeopathic pathogenetic experimentation proved to be an effective method to observe the idiosyncratic manifestations of human individuality based on qualitative methodology, thus building a basis of understanding of homeopathy.

Progress of component design methods for bulk metallic glass

The development and application of the component design methods for bulk metallic glasses are summarized. And then, their application scopes are analyzed, respectively. Moreover, we propose a new method titled as similitude principle and artificial neural network model (SPANNM) for the component design and glass forming ability of bulk metallic glasses. It is shown that the predicted results by the SPANNM are in better agreement with the experimental values.

Homeopatia: ciência, filosofia e arte de curar

O texto busca esclarecer as peculiaridades da homeopatia que, apesar de fazer parte do rol das especialidades médicas brasileiras desde 1980, não é ensinada na maioria das escolas médicas. Associada a esta lacuna na educação dos estudantes de medicina, a aplicação de pressupostos distintos dos propagados pela ciência hegemônica contribui à disseminação de preconceitos arraigados à cultura médica, afastando graduandos e graduados do aprendizado de uma prática bisecular que deveria estar incorporada ao arsenal terapêutico vigente. Empregando um princípio de cura que estimula o organismo a reagir contra sua enfermidade (princípio da similitude) e valorizando a individualidade enferma em seus aspectos bio-psico-sócio-espirituais, o modelo homeopático favorece a relação médico-paciente e estimula o raciocínio holístico na compreensão do complexo fenômeno do adoecimento humano, propiciando uma terapêutica de baixo custo, isenta dos efeitos colaterais dos fármacos modernos e que incrementa a resolutividade clínica das doenças crônicas em geral.

Dislocation patterning during crystal growth of semiconductor compounds (GaAs)

The phenomenon of dislocation patterning during melt growth of semiconductor compound crystals is discussed. The paper is focused on the formation of cellular structures in GaAs driven by thermomechanical stresses during the growth process. Undoped GaAs crystals show dislocation cell patterns with cell dimensions in the range 0·1–2 mm, orders of magnitude larger than in deformed metals. However, the correlation between cell diameter and dislocation density follows the same relation. Experimental results on the dislocation structure in GaAs were correlated with simulations of the resolved shear stress distribution based on a global temperature field simulation and scaled with the Taylor relation d=Kρ−½ and the similitude principle d=αKGbτ−1 (d is cell diameter, ρ is dislocation density, G is shear modulus, b is Burgers vector, τ is resolved shear stress, and α and K are proportionality factors). GaAs samples grown from a Ga rich melt with in situ control of stoichiometry show almost no dislocation patterning.

Similitude des structures métalliques sous chargement dynamique rapide

This paper draw a picture of the work carried out by the French Shipbuilding Research Institute in NASPA project NASPA (Nouvelles Approches de la Sécurité Passive dans les Transports). This work is dedicated to establishment of theoretical similitude law in crash analysis of steel structure together with comparison to practical law. It is based on numerical finite element simulations, crash trial tests and an original approach called non-direct similitude. It demonstrates present capabilities to easily replace full-scale trials by simulation and small-scale trials to assess at lower cost the collision behaviour of a steel structure. The introduced method uses the non-direct similitude principle applied to numerical simulation couple to trial tests on reduced models.

Homeopathic use of modern medicines: utilisation of the curative rebound effect

Homeopathy is a therapeutic method based on the application of the similitude principle, utilising medicinal substances that produce effects that are similar to the symptoms being treated. In this process, the organism is stimulated to react against its own disturbances through a vital (paradoxical, secondary or homeostatic) reaction, oriented by the primary effect of the used drug. This effect should have properties that are similar to the symptom that is being treated. This secondary reaction of the organism to a medicinal stimulus is observed in hundreds of modern drugs, and is referred to as a rebound effect. In this study we propose the utilisation of modern drugs according to the principle of homeopathic cure, employing the rebound effect as a curative reaction. For that we suggest the compilation of a Common Materia Medica that would group all symptoms produced by the medications in human individuals (therapeutic, adverse and side effects), utilising them, a posteriori, following a partial or total similitude, in minimal or ponderous doses. By doing that, we can take advantage of the numerous modern pharmacological compendiums, amplifying the spectrum of homeopathic cure with a wide range of new symptoms and medications.

Application of similitude principle to the numerical simulation of solar atmospheric dynamics

Numerical simulation has become a tool for the investigation of detailed physical structures of solar atmospheric dynamics. This tool has become an essential part of solar physics because the complexity of nonlinear characteristics of much solar phenomena renders the achievement of analytical solutions to be difficult to obtain. Although computer technology and numerical methods have made significant progress in recent years, realistic simulation for some prototype physical systems (for example: the birth and decay of an active region) still is not possible because of the wide range of spatial and time scales that must be considered. Therefore, proper scaling rules must be recognized for the development of appropriate models. In this paper, we shall apply the similitude principle to develop these scaling rules for problems of solar atmospheric dynamics. It is found that these rules are highly dependent on the physical nature of the specific problem under consideration. A set of “similitude critiques” is presented for some specific physical conditions. Numerical examples of coronal dynamic response and active region dynamics are used to demonstrate these new ideas.

Torsion Resilience Pendulum

Abstract A resilience measuring pendulum, where potential energy is stored in elastic form inside a twisted metal wire, rather than in the more customary gravitational form, is described. The device is of very simple construction and use and, applying it to various test piece thicknesses through the use of the mechanical similitude principle, shows a remarkable accuracy.

The Effect of Displacement Currents on the High-Frequency Resistance of Circular Single-Layer Coils

In existing theoretical formulas for obtaining the high-frequency resistance of circular single-layer coils, the effect of displacement currents has been neglected. It was thought that the displacement currents in going from one turn of the coil to another through the dielectric, would affect the distribution of current over the cross section of the conductor and, consequently, the effective resistance at high frequencies. The present paper shows that this effect is of minor importance by applying, for the first time, the similitude principle to circular single-layer coils. The paper also experimentally substantiates the results predicted by the similitude principle.