Elementary Forces Research Articles

Futurist mediterraneità between Emporium and Imperium

Futurist mediterraneità between Emporium and Imperium Claudio Fogu "In the golden years of rationalist architecture, Mediterranean-ness became our polar star" (Carlo Belli, cited in Danesi, 25). Thus architectural and art critic Belli recalled in 1976 the key role that the idea of mediterraneità (Mediterranean-ness) had come to play for both avant-garde Italian artists and rationalist architects in the early 1930s. Whether identified with a modern sense of the "classic" intended as an art of "intimacy cum narrative depth"—which accommodated equally the abstractism of Milanese painters, the "scuola Romana" of Giuseppe Capogrossi, Emanuele Cavalli e Corrado Cagli, and "les Italiens de Paris" united around Giorgio De Chirico—or with the "solar-ness" of Italian-rationalist architecture, Mediterranean-ness became the most effective line of defense in the Italian-modernist town (Vescovo 24). It allowed Italian modernists under Fascism to unify around a common discursive strategy in order to simultaneously distinguish themselves from their Northern European rivals, and to fence off the increasingly worrisome accusations of esterofilia (love of everything foreign) levied against them by the ever more vocal proponents of an official fascist style responding to the idea of romanità (ancient Roman-ness) (Benzi 30). Already between 1928 and 1929, Italian emigré painters in Paris, from the ex-futurist Gino Severini to the sui generis novecentisti Massimo Campigli and Filippo De Pisis, gathered around De Chirico, father of the most intuitively Mediterranean style in painting (metafisica), to combine "magical realism" and "abstract classicism" in order to create a Mediterranean alternative to the Surrealist "appeals to the unconscious, unexplored lands, and elementary forces"(Benzi 31).Similarly, in 1931, [End Page 25] the rationalist architects known as Gruppo 7 began their polemic against the "cold rationalism" and "socialistic" tendencies of Bauhaus architecture, opposing to it the "solar" and "spontaneous" rationalism of Southern Italian and Greek islands architecture (Danesi 25). Pointing to the geographical consistency of the connection between sun, Mediterranean sea, and white walls-architecture, and linking it to the diachronic consistency of climate and natural landscape across the Mediterranean area, the adherents to the most foreign-inspired modernist trend—rationalist architecture—could thus construct, a posteriori, a most convenient national-natural foundation for their daring architectural choices. Modern architecture was projected to be a natural outgrowth of Mediterranean climate and that had always been there in the combination of solar whiteness and sezione aurea (Golden section), characterizing even the so-called spontaneous architecture of Mediterranean islands. But was mediterraneità anything more than a politically convenient strategy for carving a vital space for the avant-garde under Fascism, while at the same time continuing to feed the cultural mill of Italian-ness? Did, for example, Malaparte-Libera's architectural masterpiece in Capri, or the villa Oro (Golden villa) by Luigi Cosenza in Naples, share substantial traits with both the centuries-old spontaneous architecture of the Corricella harbor in the island of Procida and the "marine landscapes" that became a statistically relevant reality of Italian-modernist painting in the second half of the 1930s? (Vescovo 20). To these questions, Belli's friend Edoardo Persico responded throughout the 1930s from the pages of the influential journal Casabella with a resounding "no." For Persico the idea of mediterraneità was as vague, rhetorical, and banal as its more official and conservative counterparts such as romanità, latinità, italianità. Worse still, a serious brand of Latin-Mediterranean modernist architecture existed, but not in Italy. It was, of course, Le Corbusier's (Danesi 25). Surely Persico's opinion was just one. But even if one were to connect more architectural and artistic dots than he was prepared to recognize as avant-garde, would the mediterraneità of Italian rationalism and metafisica amount to much more than a certain suggestion of the naturalness of the classic, an idea of natural purity distilled from the sea and bathed in light, an abstract genealogy without the burden of history? Where, in other words, was the "modern" element in this Mediterranean-ness? This question was never addressed by Persico, nor by champions...

Unity of Elementary Particles and Forces in Higher Dimensions

The idea of unifying all the gauge and Yukawa forces as well as the gauge, Higgs, and fermionic matter particles naturally leads us to a simple gauge symmetry in higher dimensions with supersymmetry. We present a model in which, for the first time, such a unification is achieved in the framework of quantum field theory.

The standard model of particle physics

Over the past three decades a compelling case has emerged for the now widely accepted standard model of elementary particles and forces. A “Standard Model” is a theoretical framework built from observation that predicts and correlates new data. The Mendeleev table of elements was an early example in chemistry; from the periodic table one could predict the properties of many hitherto unstudied elements and compounds. Nonrelativistic quantum theory is another standard model that has correlated the results of countless experiments. Like its precursors in other fields, the standard model of particle physics has been enormously successful in predicting a wide range of phenomena. And, just as ordinary quantum mechanics fails in the relativistic limit, we do not expect the standard model to be valid at arbitrarily short distances. However, its remarkable success strongly suggests that the standard model will remain an excellent approximation to nature at distance scales as small as 10–18 m.

Microscopic approaches to dynamics and structure of biological motors

It has become increasingly clear that the interior of biological cells, the cytoplasm, is intricately organized and ordered by complex networks of protein polymers and membranes. Transport processes, as well as large-scale mechanical processes, are driven within cells by a multitude of motor proteins interacting with these networks. New experimental techniques are now making it possible to directly observe the molecular dynamic processes at the basis of this machinery, and a detailed understanding of the parts of the machinery is emerging. Elementary displacements and forces produced by single molecules have been observed for several motor proteins.

Exploring the elementary harmonic forces in the tonal system

To study the elementary expectations that arise in the perception of tonal music, an exploratory study was performed in which subjects heard a sequence of four chords (to induce a key or tonality) followed by one tone (1 of the 12 tones within an octave), and indicated which tone they expected to be the next tone. Responses were divided into three groups: a random, a fifth, and a tonal group. The expectations in the tonal group are of main interest, as they seem to originate from a tonal representation. In this representation the tonic attracts almost all tones, although to different degrees, while the dominant and the mediant function as centripetal centers that attract only nearby tones. A preliminary model for the formation of elementary expectations based on a 3-level mental representation of the tones in a key is proposed, The predictive capability of the model is compared to that of existing models.

Spiral defects in motility assays: A measure of motor protein force.

In a commonly used motility assay, cytoskeletal filaments are observed as they glide over a surface coated with motor proteins. Defects in the motion frequently interrupt the flow of filaments. Examination of one such defect, in which a filament adopts a spiral form and rotates about a fixed point, provides a simple measure of the force exerted by the motor proteins. We demonstrate the universality of this approach by estimating the elementary forces of both myosin and kinesin.

The matching effect in superconducting layered structures

Multilayers based on Nb/NbO x (S-I-S) were investigated in external magnetic fields at various temperatures. It was found that the shear deformation of the solid vortex lattice determines critical current density in the case of large period structures and high parallel fields. The solid vortex lattice can be destroyed by decreasing both the period and the upper critical field. The qualitative change of the magnetic field dependence of the volume pinning force was observed as the temperature was increasing. It reveals structural transition from an elastically deformed flux line lattice to a plastically deformed one. Thus the scaling law is destroyed for these structures. We have determined the volume pinning force by direct summing of elementary pinning forces in oxide layers in this case.

The superconducting mixed state of artificial microstructures

Abstract The use of ordered microstructures makes it possible, on the one hand, to obtain new (including quantitative) information on elementary pinning forces and on methods of their summation and, on the other hand, to observe interesting effects based on the coherent behaviour of Abrikosov vortices in them. Some progress in these fields of research, has been achieved at the present time. We believe that today the study of quasiperiodic structures and, in particular, pinning in these structures, is also a topical problem. This is because these structures are an intermediate case between fully ordered superconducting lattices and the chaotic system of pinning centres which exists in ordinary superconductors. One of the basic objectives of this review was to demonstrate the existence of interesting problems from the viewpoints of both fundamental and applied physics in this area. It should also be stated that because of the rapid development of technology it is hoped that soon it will be possible to create both more complex and more advanced microstructures, specifically for improving the critical parameters of superconducting materials. This also shows the importance of this field of research.

Critical currents in Y 1Ba 2Cu 3O 7−δ thin films containing screw dislocations

Flux pinning by screw dislocations and (oxygen) vacancies is considered in Y 1Ba 2Cu 3O 7−δ thin films. Expressions for the corresponding elementary pinning forces are given and estimates concerning their strengths are made. It is supposed that the screw dislocations are the predominant pinning mechanism up to a (low) field value B sc where all strong pinning sites due to the screw dislocations are occupied. At high fields, (oxygen) vacancies in the CuO 2 planes are proposed to be the main source of pinning. The different temperature dependences may be used to discriminate between these pinning mechanisms. In order to check this model, the critical current was measured on a film with a certain screw dislocation density by means of transport and irreversible magnetization measurements. At low fields (0.05 and 0.075 T), the temperature dependence of measured critical current density could be well described by pinning due to screw dislocations, whereas at higher fields (up to 6 T) the temperature dependence resembled that for pinning due to oxygen vacancies, though the agreement was less satisfactory. We conclude that the assumptions concerning the pinning behaviour were reasonably confirmed.

The SU(8) GUT for chiral families

We argue that there is a natural inclusion of the standard model with the family-unified chiral local symmetry SU(3) H in a new SU(8) GUT inspired by Georgi's SU(11) model. The SU(8) symmetry breaking along the chain with the intermediate electro-weak-horizontal unification SU(8)→SU(5) EWH×SU(3) c×U(1) is proved d to be the distinguished pattern. The model predicts a long-lived proton (10 33–10 35yr) and practically the observed value of the Weinberg angle, in sharp contrast to the ordinary GUTs. The observation of the specific flavour-changing baryon decays ( p→ π, μ, Ke,…) could unambiguously single out the flavour unified GUTs as well as confirm the existence of the elementary horizontal forces at small distances.

Statistical variations of the elementary flux-pinning force and their effect on the shape of the bulk-pinning-force curve of high-field superconductors

It is a common procedure to infer the flux-pinning mechanism from the shape of the bulk-pinning-force curve [${\mathit{F}}_{\mathit{p}}$(b)]. In this paper, we investigate the effects of having a distribution of elementary pinning forces (${\mathit{f}}_{\mathit{p}}$) on ${\mathit{F}}_{\mathit{p}}$(b) within the framework of fluxon core pinning and full summation. It is seen that the shape of ${\mathit{F}}_{\mathit{p}}$(b) can be significantly changed when the pins are strong and their ${\mathit{f}}_{\mathit{p}}$ distribution broad, whereas traditional ideas accept that its shape remains constant. A shift of the peak of ${\mathit{F}}_{\mathit{p}}$(b) to lower field and an increase in the curvature of the high-field portion of ${\mathit{F}}_{\mathit{p}}$(b) is seen. We find confirmation of the model in optimized high-${\mathit{J}}_{\mathit{c}}$ Nb-Ti composites, which have a broad distribution of \ensuremath{\alpha}-Ti precipitate thicknesses.

Direct summation of elementary pinning forces for Nb-Ti superconductors with a field-dependent probability function

As T to Tc the field dependence of Fp for optimized, high-Jc Nb-Ti changes progressively from b(1-b) to approximately b(1-b)2.5, a result which has no explanation. The authors investigate the influence of a pinning probability function P(b) on the field dependence of Fp. The elementary pinning force (fp) for a core-pinning interaction may be greater than the value which would be obtained for a random sampling of the pins ((fp)) because the pins which have an above-average strength will be occupied with higher probability. As the field increases, the field-independent line energy becomes stronger than the decreasing pinning energy, and the deviations necessary for the selection of above-average pins occur less often. The difference between fp and (fp), which is proportional to P(b), accordingly decreases. From direct summation, Fp approximately=(B/ phi 0).fp, and because the field dependence of fp is proportional to 1-b (due to the core interaction) and also to P(b), the field dependence of Fp is proportional to b(1-b)P(b). This may resolve the Fp results.

Destruction of Scalino Law for Flux Pinning in Layered Structures

ABSTRACTThe multilayers based on Nb/NbO (S-I-S) were investigated in external magnetic fields at various temperatures. It was found that the shear deformation of the solid vortex lattice de-termenes critical current density in the case of large period structures and high parallel fields. The solid vortex lattice can be destroyed by decreasing of both the period and the upper critical field. The qualitative change of the magnetic field dependence of the volume pinning force was observed as temperature was increasing. It reveals structural transitioon from elasti-cally deformed flux line lattice to plastically deformed one. Thus the scaling low is destructed for these structures. We have determened the volume pinning force by direct summing of elementary pinning forces in oxide layers in this case.

船舶風圧力データの力学モデルによる解析-II

A physical-mathematical model consisting of six elementary fluid dynamic forces and stall effects acting on a ship was proposed by the authors. After that analysis, K. Karasuno et al. examined specific fluid forces in the model, such as induced drag, cross flow drag and stall effects. This examination generated the new mathematical model. In this paper, the data presented in previous papers concerning wind forces on various types of ships were analyzed using this new mathematical model. As a result, it was found that these model formulae could well describe measured forces and give reasonable physical meanings to the formulae in terms of fluid dynamics. For the estimation of fluid dynamic forces, correlation between the coefficients of wind forces and six nondimensional hull parameters (aspect ratio, B/L, B/H, T/L, X/L, and Ax/Ay), and the correlation between wind forces coefficients were examined. The coefficients of correlations between some parameters or fluid dynamic coefficients had significant levels in these references. Therefore, each fluid dynamic coefficient of wind forces could be estimated from nondimensional hull parameters and the correlation between fluid dynamic coefficients.

The Z Boson

The discovery of the Z boson 7 years ago verified a key prediction of the unified theory of electromagnetic and weak forces. Today an experimental program is beginning at two electron-positron colliders to study the properties of the Z particle in great detail. The data accumulated will subject the unified theory to more rigorous tests and will probe with great sensitivity for new physics not encompassed by the existing standard model of the elementary particles and forces. Questions under study include the number of quark and lepton families, the mass of the still undiscovered top quark, and the search for the still unknown fifth force of nature required by the theory to generate the masses of the elementary particles.

Critical currents and flux pinning in Ag stabilized high Tc superconductor wires

Y 1Ba 2Cu 3O 7− x and Bi 2Sr 2Ca 1Cu 2O 8+ x Ag sheathed high T c superconductor wires have been prepared using the powder in tube technique. Characterization of wire specimens was performed mainly by measuring critical current densities at 77 K and 4.2 K, as well as by a.c. susceptibility measurements. Whereas the critical current density in Y 1Ba 2Cu 3O 7− x /Ag wires is limited by weak links, there are virtually no weak links present in Bi 2Sr 2Ca 1Cu 2O 8+ x /Ag wires. Above ≈20 K, critical current density in this material seems to be limited by flux creep. At lower temperatures flux creep becomes insignificant. At 4.2 K critical current densities of up to 5.7 × 10 4 A cm −2 in zero magnetic field and of up to 1.5 × 10 4 A cm −2 in a field of 26 T could be achieved, rendering possible the use of this material for very high field application. The results will be compared with those obtained on conventional metallic Nb-Ti superconductor wires. Flux pinning in these materials will be discussed, based on a model of direct summation of elementary pinning forces.

船舶風圧力データの力学モデルによる解析

A physical-mathematical model consisting of six elementary fluid dynamic forces and stall effects acting on a ship is proposed by the authors. They then examine specific fluid forces in the model, such as induced drag, cross flow drag and stall effects. This examination generated a new mathematical model. In this paper, data presented in previous papers concerning wind forces on various types of ships was analysed using this new mathematical model. It was found that these formulae could describe measured forces and give reasonable physical representations of the formulae in terms of fluid dynamics. For the estimation of fluid dynamic forces, correlation between the coefficients of wind forces and six nondiemnsional hull parameters (aspect ratio, B/L, B/H, T/L, X/L and Ax/Ay), and the correlation between wind force coefficients were examined. The coefficients of correlations between some parameters or fluid dynamic coefficients had significant levels in these cases. Therefore, each fluid dynamic coefficient of wind forces could be estimated from nondimensional hull parameters and the correlation between fluid dynamic coefficients.

A discrete geometry: Speculations on a new framework for classical electrodynamics

An attempt is made to describe the basic principles of physics in terms of discrete partially ordered sets. Geometric ideas are introduced by means of an action at a distance formulation of classical electrodynamics. The speculations are in two main directions: (i) Gravity, one of the four elementary forces of nature, seems to be fundamentally different from the other three forces. Could it be that gravity can be explained as a natural consequence of the discrete structure? (ii) The problem of the observer in quantum mechanics continues to cause conceptual problems. Can quantum statistics be explained in terms of finite ensembles of possible partially ordered sets? The development is guided at all stages by reference to the simplest, and most well-established principles of physics.

Unification of interactions and the constraint on charges in fermion-scalar constituent models.

It is shown that the unification of elementary forces in scalar-fermion preon models depends on the normalization condition imposed on the preonic charge operator Q. One can demand that the normalization of Q equals the normalization of hypercolor and color gauge operators. Alternatively one can construct a simple covering gauge group, which in a plausible way leads to different normalization. Unification, at a reasonable scale M (Mapprox.10/sup 15/ to 10/sup 16/ GeV) imposes some conditions on preonic charges, which are not quite the same for both approaches, which were discussed above. The unification follows for a wider range of parameters in a model in which one fermionic preon transforms as a color triplet, and there is a definitive distinction between two classes of scalar-fermion preon models. The drawback of the approach based on the unification group SU(7) is that it introduces a large number of ''exotic'' preons (i.e., those which do not appear in the composites: quarks, leptons, etc., the total number of preons, 64, is also unacceptably large). It also has some difficulty with the magnitudes of the hypercolor scale and the unification scale.

Elementary Particles and Forces

T he notion that a fundamental simplicity l ies below the ob­ served diversity of the universe has carried physics far. Historically the l ist of particles and forces consid­ ered to be elementary has changed continually as closer scrutiny of mat­ ter and its interactions revealed micro­ cosms within microcosms: atoms with­ in molecules, nuclei and electrons withi,n atoms, and successively deeper levels of structure within the nucleus. Over the past decade, however, experi­ mental results and the convergence of theoretical ideas have brought new co­ herence to the subject of particle phys­ ics, raising hopes that an enduring un­ derstanding of the laws of nature is within reach. Higher accelerator energies have made it possible to collide particles with greater violence, revealing the subatomic realm in correspondingly finer detail; the l imit of experimental resolution now stands at about 1 0-16 centimeter, about a thousandth the d iameter of a proton. A decade ago physics recognized hundreds of appar­ ently elementary particles; at today's resolution that d iversity has been shown to represent combinations of a much smaller number of fundamental entities. Meanwhile the forces through which these constituents interact have begun to display underlying similari­ ties. A deep connection between two of the forces, electromagnetism and the weak force that is familiar in nu­ clear decay, has been established, and prospects are good for a description of fundamental forces that also en­ compasses the strong force that b inds atomic nuClei. Of the particles that now appear to be structureless and indivisible, and therefore fundamental, those that are not affected by the strong force are known as leptons. Six d istinct types, fancifully called flavors, of lepton have been identified. Three of the lep­ tons, the electron, the muon and the