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Aluminum based alloys of the 5xxx series are identified by a high magnesium content (4÷4.9%) which through its compounds can induce special properties of mechanical strength and resistance to various forms of corrosion. The use of 5083 aluminum alloy is especially intended for pressure vessels, products that work in special conditions of temperature and environment with increased aggressiveness, which requires the request in specifications of special properties, especially in the test of resilience. This paper aims to define the best combination of heat treatments, either homogenization or homogenization and artificial aging, in order to obtain the best mechanical and structural characteristics. Two homogenizations were carried out on the cast products (at 350°C and 450° C, respectively), each followed by artificial aging (180°C or 140°C), with different maintenance times, respectively 1h, 12h and 24h). Finally, structural correlations could be made between the values of mechanical properties (yield strength, hardness, tensile strength, elongation, microhardness and resilience) and the grain size corresponding to each structural condition.

Aluminum based alloys are widely used as applications for heat exchangers, especially for car radiators. The main alloy used is 3003 (in according with ISO6361), which is usually plated with a 4000 series alloy (which has a lower melting point). The present paper gives a comparative analysis of the mechanical characteristics values of the 3003 alloy plated sheets, in different states (state O and state H24), and different sheet thicknesses (0.5 mm, 0.97 mm, and 2 mm respectively). Statistical comparative analysis shows that the considered processes are stable (in control) in the sense of control chart (X chart and R chart values) are within the control limits and there are no specific trends. The stability of the processes was highlighted by the use of performance indices. Thus, the CPK performance index in all the analyzed situations is much higher than 1.33, which means that the processes are stable with a normal distribution of values. Instead, the PPK capability index values are much lower than CPK. The distribution of elongation values (in state O, at a thickness of 0.97 mm - with the value of the PPK capability index 1.95 and in state O 2.5 mm thickness - with the value of the PPK capacity index 2.25 mm) has a value greater than 1.67, which indicates that this characteristic is in a state of statistical control (ie PPK ≥ 1.67 and CPK ≥ 1.33). The fact that for the other characteristics the value of the PPK ≤ 1.67 capability index, and yet the process is stable, means that there must be process improvements through various corrective measures until continuous stability is achieved. The complete statistical analysis, performed on the values of the mechanical characteristics, of the 3003 alloy plated sheets, in different delivery states and different thicknesses, showed, finally, that the applied technological processes led to obtaining appropriate mechanical characteristics, without deviating from outside the limits of tolerance, with high reproducibility and stability.

Magnetic fluids based on single-domain magnetic spinel ferrite nanoparticles dispersed in various liquid media are of particular practical and scientific interest. This paper presents a muon spectroscopy study of a ferrofluid based on magnetic nanoparticles of CoFe2O4 molecules dispersed in water (H2O) with a nanoparticle concentration of 3%. In this study, it was determined that the structure and magnitude of the magnetization of a ferrofluid depend on the viscosity of the liquid itself. It was shown that, at room temperature (290 K) and under an external magnetic field of 527 G, the observed additional magnetization was ~20 G. In a small fraction of the sample under study (~20%), negative magnetization (diamagnetism) was observed. At low temperatures (~30 K), the sample acted as a paramagnet in a magnetic field. For the first time, the magnetic field inside and in the immediate vicinity of a CoFe2O4 nanoparticle has been measured experimentally using the μSR method: the value was 1.96 ± 0.44 kG, thus, direct measurement of the magnetization of a nanoscale object was performed.

The diffusion coeffs., Dij, for the ternary system water + chloroform + acetic acid are reported at 5 compns. This system presents a large soly. gap due to the almost complete insoly. between water and chloroform. The analyzed compns. have a fixed mole ratio of water and chloroform and a decreasing amt. of acetic acid when approaching the binodal curve. The difficulty of interpreting the Dij is stressed, and the use of different choices of which component is the solvent and a different ref. frame for the diffusive transport is suggested to ext. all the possible information from the diffusion coeffs.

A theoretical spinodal curve for the system water + chloroform + acetic acid at 25 °C is derived using a lattice model for ternary amphiphilic solutions: rod-like molecules covering the bonds of the honeycomb lattice with three-body interactions between the molecular ends associated to the same lattice site. The molecular model is equivalent to the standard Ising model on the same lattice; its mean-field solution is the most appropriate for reproducing, by local fitting, the experimental data for the binodal composition. The derived spinodal curve is in very good agreement with the spinodal composition determined also in the present work from the measured diffusion coefficients recently reported for the same system.

Electroflotocoagulation is used for the treatment of liquid wastes of various origins, containing suspended matter. The metal hydroxide formed by electrochemical metallic ions generation acts to aggregate the colloidal impurities, and the hydrogen bubbles evolved at the cathode allow flotation of foam containing the impurities. The aggregates formed (containing the impurities) and lifted above the solution can then be removed. Electroflotocoagulation (simultaneous electrocoagulation and electroflotation) is studied as partially treatment method for non-ferrous heavy metals metallurgy wastewater (levigates). A pilot scale reactor for electroflotocoagulation is proposed. Different parameters are studied: pH variation during the process, anodic and cathodic current densities, cell voltage, energy consumption, hydrogen evolution etc.

The diffusion coefficients, D ij , for the ternary system water + chloroform + acetic acid are reported at five compositions. This system presents a large solubility gap due to the almost complete insolubility between water and chloroform. The analyzed compositions have a fixed mole ratio of water and chloroform and a decreasing amount of acetic acid when approaching the binodal curve. The difficulty of interpreting the D ij is stressed, and the use of different choices of which component is the solvent and a different reference frame for the diffusive transport is suggested to extract all the possible information from the diffusion coefficients.

A model is considered in which the bonds of a honeycomb lattice are covered by rodlike molecules of types AA, BB, and AB. Neighboring molecular ends have three-body and orientation-dependent interactions. The model is shown to be equivalent to a spin-1/2 Ising model on the same lattice with a field, but with only pairwise interactions. Symmetric and asymmetric coexistence surfaces for the separation into an AA-rich and a BB-rich phase are calculated exactly.

A model three-component system is considered in which the bonds of a honeycomb lattice are covered by bifunctional molecules of types AA, BB, and AB. The AB type molecule represents an amphiphile. An accurate approximation to the boundary in temperature-composition space of an ordered amphiphile-rich phase is calculated by transforming an accurate closed-form approximation of the critical frontier of an antiferromagnetic phase in an equivalent Ising model. This Ising model has coupling constants and a magnetic field that are temperature dependent.

We consider a lattice model for ternary solutions in which the lattice bonds are covered by molecules of types AA, BB, and AB, and the only interactions are between the molecular ends of a common lattice site. Using its equivalence with the standard Ising model for magnets, we derive the spinodal curve of the three-component model on the honeycomb lattice in the mean-field and Bethe-lattice approximations. The spinodal and the coexistence curves of the ternary solution are drawn at different values of the reduced temperature, the only parameter of the model. The particular case of a binary solution is also illustrated.

The canonical transformation diagonalizing the one-particle tight binding Hamiltonian for an alternating chain with two non-equivalent sites per unit cell has been used to introduce the Hubbard-like interactions (on-site, inter-site, bond-site and intra-bond) in the corresponding two-band model. The considerations have been restricted to the particular case, suggested by the undistorted 3/4-filled $CuO_{3}$ chain, where the alternating structure comes only from non-equal on-site atomic energies and the gap between the two bands is sufficiently large. The renormalization group method has been then applied to the upper band of this model and the corresponding phase diagram has been analyzed in terms of some renormalized (density dependent) Hubbard-type couplings for arbitrary filling of the upper band. The particular case of $CuO_{3}$ chain is also discussed and the corresponding phase diagram has been drawn in terms of the original (and realistic) coupling constants.

The interpretation of the OZI-rule violation in the reaction p p → Φπ 0 encounters difficulties since one cannot exclude the possibility that the violation is a consequence of the rescattering in the final state. For this reason it is important to seek reactions in which the OZI-rule violation cannot be explained by conventional mechanisms. We compute the rescattering contribution in the reaction p p → f′ 2 π 0 and show that this contribution is negligible. Therefore any substantial OZI-rule violation in the process p p → f′ 2 π 0 would undoubtedly mean that some unusual physics plays an important role in this process.

We explicitly calculate in the on-shell approximation the contribution of the triangle mechanism with K ∗ and K mesons in the intermediate states to the branching ratios of the reactions p n → φπ − , p p → φπ 0 and p p → φγ , the experimental values of which strongly disagree with the OZI-rule predictions. The calculated branching ratios for the first two reactions are in qualitative agreement with experimental data while even the upper bound for the branching ratio of the latter reaction is much less than the corresponding experimental value. We also discuss the contribution of the above mechanism to the reactions p p → φη, p p → φρ 0 and p p → φω .

A model is presented in which the bonds of a honeycomb lattice are covered by rodlike molecules of types AA and BB, molecular ends near a common site having both three-body interactions and orientation-dependent bonding between two A molecular ends and between an A and a B molecular end. Phase diagrams corresponding to the separation into AA-rich and BB-rich phases are calculated exactly. Depending on the relative strengths of the interactions, one of several qualitatively different types of phase diagrams can result, including diagrams containing phenomena such as a double critical point or two separate asymmetric closed loops. The model is essentially a limiting case of a previously considered ternary solution model, and it is equivalent to a two-component system of interacting A and B molecules on the sites of a kagomé lattice.

We consider the problem whether the rescattering mechanism with {ital K}{sup *}{ital {bar K}} and {ital {bar K}}{sup *}{ital K} intermediate states, which qualitatively explains the large Okubo-Zweig-Iizuka rule violation in the reaction {ital {bar p}p}{r_arrow}{phi}{pi}{sup 0} when the {ital {bar p}p} system annihilates from the {ital S} state of the hydrogenlike {ital {bar p}p} atom, is compatible with the fact that this reaction is not seen in the annihilation from the {ital P} state.

A review of the problem of whether the violation of the OZI rule in nucleon–antinucleon annihilation at rest can be explained in the framework of conventional mechanisms is given in detail. While the vector-dominance model and the rescattering model qualitatively describe the OZI-rule violation in the reactions pp→φγ and pp→φπ 0 for the annihilation from the S state of the protonium atom, the latter model cannot explain the fact that the annihilation into φπ 0 from the P state is not seen and the OZI rule in the reaction pp→f 2 ′ π 0 is not satisfied. We also discuss what information about the OZI-rule violation can be extracted from the reaction pp→φπ + π − and decays of the J/Ψ meson.

We reply to the Comment by Bingsong Zou. {copyright} {ital 1996 The American Physical Society.}

The four mutual diffusion coeffs. have been detd. for two sets of homogeneous compns. of the water + chloroform + acetic acid system at 25C. By extrapolating the values of the diffusion coeffs. determinant in the supersatd. region, we detd. the spinodal compns. for two sets of expts. The comparison between the exptl. results and the theor. prediction of the spinodal curve within an extended Wheeler-Widom model shows an excellent agreement.