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Key-joints and splined shafts are used in many drives and rotating elements in engineering practice. Nowadays it is increasingly important to decrease the dead-weight of structures (in the vehicle industry, aircraft industry, etc). This paper shows an optimization process for the minimum weight design of key-joints. For the solution of the optimization problem a 3D grapho-analytical optimization process is used, based on the Kuhn-Tucker optimality criterion. During the graphic part of the process, three-dimensional diagrams show the behavior of the objective function and of the design constraints, which makes easy to read the optimum solution from the diagram. The final optimum solution is also given numerically in a table. For better demonstration, the finite element analysis of the three-dimensional CAD model of the optimal joint is also shown. As a further application, the grapho-analytical optimization of parallel key splined shafts is shown, too. [ABSTRACT FROM AUTHOR]

Chatter is a self-excited vibration that takes place during turning operations. It is either to be avoided or reduced for its negative impact on the machine-tool, the workpiece surface finish, and the cutting tool life. A lot of research has been carried out in this domain to understand this phenomenon, which leads to finding ways to detect, identify, avoid, reduce, and control chatter in turning processes. In this paper, chatter research related to turning processes is reviewed and summarized. The main goal of this review paper is to compare different chatter prediction, suppression, and avoidance techniques to find out the most effective technique, so a scope of a work related to turning processes chatter is defined. [ABSTRACT FROM AUTHOR]

The goal of this study is to dynamically simulate a turning-centre main spindle system utilizing the systems receptance coupling technique to determine the spindle system's first three resonant frequencies in the event of transverse vibrations. The findings are then confirmed using the finite element technique using ANSYS software. The significance of analysing the spindle system described in this study is that it can be utilized to optimize the spindle system in terms of resonance frequencies for improved performance in terms of spindle vibration while the turning centre is in operation. [ABSTRACT FROM AUTHOR]

Differential scanning calorimetric analysis of multilamellar liposomes of 2,3-dipalmitoyl-sn-glycero-1-phosphocholine (DPPC) suggests that cholesterol exists as interlamellar tail-to-tail dimer in the DPPC bilayers. In the fully extended state, solid cholesterol is interspersed with solid-ordered domains. Cholesterol enhances the stability of the bilayer and the dissolution of lipids in the phospholipid bilayer.

The inhibitory activity of Bis (heteroaryl) piperazine U-88204 E on HIV-1 reverse transcriptase (RT) is analogous to that of AZT, ddI, ddC is useful in the treatment of AIDS patients. Thus, there is a great need for research involving RT inhibitors. U-88204E exhibits antiviral activity at nontoxic doses in the HIV-1 populated lymphocytes in cultured tissues.

The influence of annealing of Gd5Ge2Si2Fex alloys at 1200°C and of alloying with various amount of iron on structure as well as thermal and magnetocaloric properties is investigated. It was found that annealing for 1 to 10 hours improves the entropy change, but reduces the temperature of maximum magnetocaloric effect by up to 50 K. Prolonged annealing of the Gd5Ge2Si2 alloy results in the decrease of entropy change due to the reduction of Gd5Ge2Si2 phase content. Addition of iron to the ternary alloy enhances the magnetocaloric effect, if x = 0.4 – 0.6, especially if alloying is combined with annealing at 1200°C: the peak value of the isothermal entropy change from 0 to 2 T increases from 3.5 to 11 J/kgK. Simultaneously, the temperature of maximum magnetocaloric effect drops to 250 K. The changes in magnetocaloric properties are related to the change in phase transformation from the second order for arc molten ternary alloy to first order in the case of annealed and/or alloyed with iron. The results of this study indicate that the minor addition of iron and heat treatment to Gd-Ge-Si alloys may be useful in improving the materials’ magnetocaloric properties..

Thermal, mechanical and magnetic properties of (Fe-Co)-(Zr/Si)-Nb-B alloys in the form of rapidly quenched rods of 1.2 mm in diameter were studied. The as-cast alloys with Zr were crystalline, and the alloys with Si were amorphous. Microhardness measured at 50 g load is from 500 to 2000 HV (the less cobalt, the higher), and the compressive strength reaches nearly 4000 MPa for Si doped alloys and 2000 MPa for Zr doped ones. This substantial difference may be attributed to partial crystallinity of the latter alloys. The magnetic hysteresis loops of fully amorphous rods measured under compression, exhibited a clear dependence of permeability vs. stress, proving that iron-based bulk metallic glasses may be promising materials for magnetoelastic force sensors.

FeCo-based soft magnetic alloys of compositions [Fe.sub.45][Co.sub.43][Cu.sub.1][B.sub.3.6][Zr.sub.7.4-x]A[M.sub.x], where x = 3.7 at.% and 7.4 at.%, and the alloying metals (AM) are Nb and Hf and were prepared in the form of amorphous ribbons by melt-spinning technique. A two-phase microstructure, consisting of [alpha]-FeCo nanocrystais and amorphous matrix, was created by partial devitrification of the amorphous alloys during annealing for 1 h at temperatures 500 [degrees]C-600 [degrees]C. The crystallization process of the amorphous alloys was studied using differential scanning calorimetry, X-ray diffractometry, and transmission electron microscopy. The quasi-static hysteresis loop was measured using an inductive method. Partial replacement of zirconium by hafnium improved thermal stability of amorphous structure and magnetic properties of the alloys studied. The effect of niobium is opposite. The best magnetic properties were found in the alloy [Fe.sub.45][Co.sub.43][Cu.sub.1][B.sub.3.7][Zr.sub.3.7][Hf.sub.3.7]. It was found that nanocrystallization temperature strongly influences the thermal stability of the magnetic properties of the alloys studied. Index Terms--FeCo alloys, HITPERM, nanocrystalline materials, soft magnetic alloys.

Temperature dependence of magnetic properties of nanocrystalline Fe60Co18Cu1B15Nb6-xZrx (x=0, 3, 6) alloys has been studied at different stages of devitrification. Transmission electron microscopy shows nanocrystals of the size ∼5 nm, which remains almost constant along the nanocrystallization process. Curie temperature of the residual amorphous phase decreases as nanocrystallization progresses for all the studied alloys. Thermal dependence of the exchange stiffness constant is obtained from the measurement of specific magnetization and coercivity as a function of crystalline fraction and temperature for the three studied alloys. [ABSTRACT FROM AUTHOR]

The temperature dependence of magnetic properties of nanocrystalline [Fe.sub.60][Co.sub.18][Cu.sub.1][B.sub.15][Nb.sub.6-x][Zr.sub.x] (x=0, 3, 6) alloys is studied at different stages of devitrification. Thermal dependence of the exchange stiffness constant is obtained from the measurement of specific magnetization and coercivity as a function of crystalline fraction and temperature for the three studied alloys.

Amorphous Fe80-xCoxZr7Si13 (x = 0-30 at.%) alloys in which boron was completely replaced by silicon as a glass forming element have been prepared by melt quenching. Partial substitution of iron by cobalt caused the increase of the hyperfine field and saturation magnetization. The specialized rf-Mössbauer measurements revealed that all amorphous alloys studied are magnetically very soft. The rf-sidebands effect, related to magnetostriction, increases with the increase of Co content. In Fe50Co30Zr7Si13 sample the rf field exposure induced partial crystallization of amorphous phase that was attributed to mechanical deformations related to high frequency magnetostrictive vibrations induced by the rf field. The measurements of the hysteresis loop revealed that coercivity increases for higher Co content. [ABSTRACT FROM AUTHOR]

This paper reports two studies. The first one investigates how two 10-year-old Taiwanese- Hungarian balanced bilingual twin boys translated sentence-embedded words between their native languages over a six-month period as the physical context around them changed. The second one compares how these two bilinguals and four monolingual children defined words in their native languages. The purpose is twofold: to explore the role of an active language in translation, and to propose a new measurement for bilinguals. The reaction time (RT) and accuracy of their verbal protocols were measured and analyzed. The bilingual children's word translation reveals an active use of metalinguistic skills. The physical context did affect their RT and accuracy in general and in translating concrete/abstract concepts. The two bilinguals defined words as fast and accurate as their monolingual peers in both languages, but different definition aspects were identified from the answers of the two groups. The translation/definition task appears a comprehensive measurement for bilingual and monolingual children with any combination of languages. [ABSTRACT FROM AUTHOR]

Abstract: The paper summarizes the current status of research in the field of magnetically soft nanocrystalline materials especially highlighting the influence of alloy composition on structure and magnetic properties as well as their stability at elevated temperature during very long time annealing (several thousand hours at temperature up to 550°C). Modification of the alloys allows to tailor their chemical composition and manufacturing process to particular application temperature requirements. FINEMET is the most suitable material for application at temperature up to 300°C, FINEMET modified by cobalt (Fe0.6Co0.4)73.5Cu1Nb3Si13.5B9 for 300°C< T <350°C, NANOPERM for 350°C< T <400°C, and HITPERM (Fe0.6Co0.4)86Hf7B6Cu1 for 400°C< T <550°C. [Copyright &y& Elsevier]

Thermospray (TSP) mass spectrometry has proved to be a useful technique for analysing various highly polar compounds. The use of a quadrupole mass spectrometer equipped with a thermospray/plasmaspray interface in the analysis of more than 30 monosaccharides and sugar derivatives is described. A 1:1 mixture of methanol or acetonitrile and 0.1 M aqueous ammonium acetate as eluent at 1 cm3 min−1 affords the best results. The correct setting of the capillary tip temperature and repeller voltage was fundamental for the ionization of carbohydrates. The/optimum values of these parameters were 240-250°C and 220-240 V, respectively. The thermospray mass spectra of most carbohydrates exhibit strong [M + NH4]+ ions which provide molecular mass information. The underivatized and derivatized monosaccharides could be grouped according to the presence or absence and the relative abundances of [M + NH4 − H2O]+, [M + H]+ and [M + NH4]+ ions. [ABSTRACT FROM AUTHOR]