Ultrasonic Measurement of Sheet Steel Texture and Formability: Comparison with Neutron Diffraction and Mechanical Measurements

Abstract

Ultrasonic measurements were made on a set of thin steel sheets, using the lowest-order shear horizontal mode (SH₀-mode) and lowest-order symmetric Lambwave mode (S₀-mode). The velocities of these modes were measured as a function of angle relative to the sheet rolling direction. From the data reduction it is, in theory, possible to (1) partially characterize the texture of the sheet, and (2) predict the plastic strain ratio (r-value). The plate texture can be completely characterized by quantities known as orientation distribution coefficients (ODCs). The lowest-order ODCs can be obtained from our measurements; these were compared with ODCs measured by neutron diffraction, with good agreement for the dominant ODC. The r-value is a commonly used measure of sheet formability. It is typically measured mechanically with uniaxial tension specimens subjected to large plastic strain. Therefore, the r-value test is destructive and time consuming. We found a good correlation between S₀-mode velocity measurements and r, the average in-plane r-value. Consequently, the use of noncontacting electromagnetic-acoustic transducers (EMATs) may offer an online nondestructive measurement of sheet formability.     

Determination of sheet steel formability using wide band electromagnetic-acoustic transducers

An electromagnetic-acoustic transducer (EMAT) system was used in conjunction with a sampled CW signal-processing method to generate, receive, and process longitudinal and shear waves in thin steel sheets. Using the system, swept-frequency measurements were made up to 7.5 MHz. To relate the measurements to sheet steel formability, a dimensionless frequency ratio,K, was computed from the resonant frequencies. From theoretical considerations,K should be related to a measure of steel sheet formability, . This parameter is traditionally measured by plastically deforming uniaxial tension specimens. Good correlation was found betweenK and for a set of steel sheet representative of those typically used to produce automobile body parts.Contribution of NIST; not subject to copyright.NIST Guest Researcher; on leave from Technical University of Plovdiv, Bulgaria.     

A combined synthetic&X chart for monitoring the process mean

The Shewhart X chart (or X chart) is widely used to monitor the mean of a quality characteristic x. This chart decides the process status based on the magnitude of the sample mean x and is effective for detecting large mean shifts. The synthetic chart is also a Shewhart type chart for monitoring the process mean, but it utilises the information about the time interval between two nonconforming samples. Here a sample is nonconforming if its x value falls beyond the predetermined warning limits. Unlike the X chart, the synthetic chart is more powerful to detect small shifts. The applications of the X and synthetic charts cover a wide variety of manufacturing processes and production lines, e.g., the monitoring of the mean values of the inside diameter of a piston-ring, the viscosity of aircraft paint, the resistivity of silicon wafers. This article proposes a combined scheme, the Syn-X chart, that comprises a synthetic chart and an X chart. The results of the performance studies show that the Syn-X chart always outperforms the individual X chart and synthetic chart under different conditions. It is more effective than the X chart and synthetic chart by 47% and 20%, respectively, over the wide range of mean shift values in different experiment runs.     

Vorhersage der thermischen Strahlung großer Kohlenwasserstoff- und Peroxid-Poolfeuer mit CFD Simulation

Flame temperatures (T), surface emissive powers (SEP) and irradiances (E) of large-scale JP-4 pool fires (d=2, 8, 16, 25 m) and di-tert-butyl peroxide (DTBP) pool fires (d=1.12 m, 3.4 m) are investigated experimentally and by CFD simulation. As experimental methods an infrared thermographic camera system with video-mixing unit is used for the determination of T, SEP and an ellipsoidal radiometer for the determination of E. The maximum frequency of time-averaged emission temperatures for JP-4 pool fire (d=16 m) are in a range of $ 793\,\mathrm{K} < \overline{T} < 1033$ and for DTBP pool fire (d=1.12 m) are a range of $ 1040\,\mathrm{K} < \overline{T} < 1480\,\mathrm{K}$ . For DTBP pool fire (d=1.12 m), the measurements result in $ \overline{\text{SEP}}\approx 130\,\mathrm{kW/m^{2}}$ which is up to a factor of ≈6 larger in comparison to hydrocarbon pool fires (d≈1 m). In a case of DTBP pool fire (d=3.4 m) with $ \overline{\text{SEP}} \approx 250\,\mathrm{kW/m^{2}}$ this factor is ≈5 compared to $ \overline{\text{SEP}} \approx 50\,\mathrm{kW/m^{2}}$ of LNG pool fire (d=4 m). By increasing the relative distance ?y/d from the pool rim, measured time averaged irradiances $ \overline{E}$ (?y/d) decrease and agree well with CFD predicted $ \overline{E}_{\text{CFD}}$ (?y/d). Also, there is a good agreement between the measured time averaged $ \overline{T}$ and $ \overline{\text{SEP}}$ of hydrocarbons and DTBP pool fires, with the predicted $ \overline{T}_{\text{CFD}}$ and $ \overline{\text{SEP}}_{\text{CFD}}$ values. The possibilities and nowadays limitations of CFD simulation of large pool fires are discussed. This study has shown that the risk potential of accidental pool fires referring to thermal radiation can be predicted much better than in the past.     

Dislocation structure at a \{ {\overline{1} 2\overline{1} 0} \}/ {\langle} 10\overline{1} 0 {\rangle} low-angle tilt grain boundary in LiNbO3

LiNbO₃ is a ferroelectric material with a rhombohedral R3c structure at room temperature. A LiNbO₃ bicrystal with a $ \{ {\overline{1} 2\overline{1} 0} \}/ {\langle}10\overline{1} 0{\rangle}$ 1° low-angle tilt grain boundary was successfully fabricated by diffusion bonding. The resultant boundary was then investigated using high-resolution TEM. The boundary composed a periodic array of dislocations with $ b = { 1}/ 3{\langle} \overline{1} 2\overline{1} 0{\rangle} $ . They dissociated into two partial dislocations by climb. A crystallographic consideration suggests that the Burgers vectors of the partial dislocations should be $ 1/ 3{\langle}01\overline{1} 0{\rangle} $ and $ 1/ 3{\langle}\overline{1} 100{\rangle} $ , and a stacking fault on $ \{ {\overline{1} 2\overline{1} 0} \} $ is formed between the two partial dislocations. From the separation distance of a partial dislocation pair, a stacking fault energy on $ \{ {\overline{1} 2\overline{1} 0} \} $ was estimated to be 0.25?J/m² on the basis of isotropic elasticity theory.     

An analytical approach and experimental confirmation of dislocation–twin boundary interactions in titanium

The morphology of $ \{ 10\overline{1} 2\} \left\langle {\overline{1} 011} \right\rangle $ { 10 1 ¯ 2 } 〈 1 ¯ 011 〉 deformation twins formed in commercial purity titanium during an initial pass of equal-channel angular pressing was studied by transmission electron microscopy (TEM). The corresponding diffraction patterns show a symmetry line splitting of $ (10\overline{1} 2) $ ( 10 1 ¯ 2 ) twin boundaries (TB) which is related to the presence of interfacial defects. A simple modeling for the interaction between non-screw a-slip lattice dislocations (Burgers vector b =  $ \frac{1}{3}[\overline{1} \overline{1} 20] $ 1 3 [ 1 ¯ 1 ¯ 20 ] ) and the $ (10\overline{1} 2) $ ( 10 1 ¯ 2 ) twin plane is used according to crystallographic geometry and vector conservation. The results show that dislocation dissociation into different Frank partial dislocations on the interfacial plane is more favorable than its transmission to the other side of the interface. The formation of the Frank partials at the TB can produce a small change in the TB misorientation angle and this is consistent with the symmetry line splitting of the $ (10\overline{1} 2) $ ( 10 1 ¯ 2 ) twin boundaries observed by TEM.     

On the use of effective limit strains to evaluate the forming severity of sheet metal parts after nonlinear loading

The conventional forming limit curve (FLC) is significantly strain path-dependent and therefore is not valid for formability evaluation of sheet metal parts that undergo nonlinear loading paths during the forming process. The stress-based forming limit curve (SFLC) is path-independent for all but very large prestrains and is a promising tool for formability evaluation. The SFLC is an ideal failure criterion for virtual forming simulations but it cannot be easily used on the shop floor as there is no straightforward experimental method to measure stresses in stamped parts. This paper presents a theoretical basis for predicting the effective limit strain curve (ELSC) using the Marciniak and Kuczynski (MK) analysis (Int J Mech Sci 9:609–620, 1967, Int J Mech Sci 15:789–805, 1973). Since the in-plane strain components are sufficient to calculate the effective strain, the ELSC can easily be determined from strains measured in the stamping plant, and therefore it is a better alternative to the SFLC for formability evaluation. This model was validated using experimental data for AISI-1012 steel (Molaei 1999) and AA-2008-T4 aluminum alloys Graf and Hosford (Metall Trans 24A:2503–2512, 1993). Predicted results showed that, similar to SFLC, the ELSC remains practically unchanged for a significant range of prestrain values under various bilinear loading paths, but some strain-path dependence can be observed for significant magnitudes of the effective prestrain (ε _e ?≥?0.37 for AISI-1012 steel and ε _e ?≥?0.25 for AA-2008-T4 aluminum).     

Gate Voltage Tuned Quantum Superconductor to Insulator Transition in an Ultrathin Bismuth Film Revisited

We explore the implications of Berezinskii–Kosterlitz–Thouless (BKT) critical behavior and variable-range hopping on the two-dimensional (2D) quantum superconductor–insulator (QSI) transition driven by tuning the gate voltage. To illustrate the potential and the implications of this scenario we analyze sheet resistance data of Parendo et al. taken on a gate voltage tuned ultrathin amorphous bismuth film. The finite size scaling analysis of the BKT-transition uncovers a limiting length L preventing the correlation length to diverge and to enter the critical regime deeply. Nevertheless the attained BKT critical regime reveals consistency with two parameter quantum scaling and an explicit quantum scaling function determined by the BKT correlation length. The two parameter scaling yields for the zero temperature critical exponents of the QSI-transition the estimates $z\overline{\nu }\simeq 3/2$ , z?3 and $\overline{\nu} \simeq 1/2$ , revealing that hyperscaling is violated and in contrast to finite temperature disorder is relevant at zero temperature. Furthermore, $z\overline{\nu }\simeq 3/2$ is also consistent with the two variable quantum scaling form associated with a variable-range hopping controlled insulating ground state.     

Nonlinear correction to Darcy’s law for channels with wavy walls

For low Reynolds numbers ${\mathcal{R}}$ , the flow of a viscous fluid through a channel is described by the well-known Darcy’s law which corresponds to a linear relation between the pressure gradient ${\overline{\nabla p}}$ and the average velocity ${\overline{u}}$ . When the channel is not straight and when the Reynolds number is not negligible, additional terms appear in this relation. Some previous authors investigated the first three coefficients in the expansion of ${|\overline{\nabla p}|}$ in the powers of ${\overline{u}}$ and they showed that the coefficient of ${\overline{u}^2}$ vanishes for moderate ${\mathcal{R}}$ . Other authors demonstrated that this coefficient can be non-zero. This question is addressed and solved. It is demonstrated that both cases occur; Forchheimer’s law has a cubic correction for small ${\mathcal{R}}$ and a quadratic one for large ${\mathcal{R}}$ . Two analytical–numerical algorithms are constructed to prove this property. These algorithms are applied to the Navier–Stokes equations in three-dimensional channels enclosed by two wavy walls whose amplitude is proportional to ${b{\varepsilon}}$ , where 2b is the mean clearance of the channels and ${\varepsilon}$ is a small dimensionless parameter. The first algorithm is applied for small ${\mathcal{R}}$ by representing the velocity and the pressure in terms of a double Taylor series in ${\mathcal{R}}$ and ${\varepsilon}$ . The accuracy ${O(\mathcal{R}^2)}$ and ${O(\varepsilon^6)}$ following Padé approximations yield analytical approximate formulae for Forchheimer’s law. The first algorithm is applied to symmetric channels on the theoretical level (all terms on ${\mathcal{R}}$ and ${\varepsilon}$ are taken into account) to show that ${|\overline{\nabla p}|}$ is an odd function of ${\overline{u}}$ . This observation yields, in particular, a cubic correction to Darcy’s law. Numerical examples for non-symmetrical channels yield the same cubic correction. The second algorithm is based on the analytical–numerical solution to the Navier–Stokes equations for arbitrary ${\mathcal{R}}$ up to ${O(\varepsilon^{3})}$ . This algorithm yields, in particular, a quadratic correction to Darcy’s law for higher ${\mathcal{R}}$ .     

The Elastic Properties, Generalized Stacking Fault Energy and Dissociated Dislocations in MgB2 Under Different Pressure

The $\langle11\overline{2}0\rangle$ perfect dislocation in MgB₂ is suggested to dissociate into two partial dislocations in an energy favorable way $\langle11\overline{2}0\rangle\rightarrow\frac{1}{2}\langle11\overline{2}0\rangle +\mathrm{SF}+\frac{1}{2}\langle11\overline{2}0\rangle$ . This dissociation style is a correction of the previous dissociation $\langle1000\rangle\rightarrow\frac{1}{3}\langle1\overline{1}00\rangle+\mathrm{SF}+\frac{1}{3}\langle2100\rangle$ proposed by Zhu et al. to model the partial dislocations and stacking fault observed by transmission electron microscopy. The latter dissociation results in a maximal stacking fault energy rather than a minimal one according to the generalized stacking fault energy calculated from first-principles methods. Furthermore, the elastic constants and anisotropy of MgB₂ under different pressure are investigated. The core structures and mobilities of the $\langle11\overline{2}0\rangle$ dissociated dislocations are studied within the modified Peierls–Nabarro (P–N) dislocation theory. The variational method is used to solve the modified P–N dislocation equation and the Peierls stress is also determined under different pressure. High pressure effects on elastic anisotropy, core structure and Peierls stress are also presented.     

A note on ‘A bivariate optimal replacement policy for a repairable system’

An error appearing in equation (3) of Y.L. Zhang (J. Appl. Prob., 1994, 31, 1123–1127) has been pointed out by S.H. Sheu (Eur. J. Oper. Res., 1999, 112, 503–516) and the correct expressions (25)–(27) given accordingly on pp. 510–511. However, the derivation of the key expression (27), the long-run expected loss rate, was not presented. The purpose of this note is threefold. First, since a monotone process (e.g. an arithmetic, geometric, or arithmetic–geometric process) approach, as discussed by K.N.F. Leung (Eng. Optimiz., 2001, 33, 473–484), is considered to be relevant, realistic, and appropriate to the modelling of a deteriorating system maintenance problem, it is worth explicitly developing this expression, which is of benefit to the subsequent studies. Secondly, equation (3) in Zhang (1994) Zhang, Y. L. 1994. A bivariate optimal replacement policy for a repairable system. J. Appl. Prob., 31: 1123–1127. [Crossref], [Web of Science ®] , [Google Scholar] is shown to be fundamentally correct and so it can be viewed as an alternative method of formulating similar bivariate cases. Thirdly, although equations (4) and (5) in Zhang (1994) Zhang, Y. L. 1994. A bivariate optimal replacement policy for a repairable system. J. Appl. Prob., 31: 1123–1127. [Crossref], [Web of Science ®] , [Google Scholar] have been logically and correctly derived, both can be readily reduced to their simplest forms which are derived here.     

Effects of interface structures on cracking in AlN(11\overline 2 0)/α-Al2O3 (1\overline 1 02) epitaxial films

The crystal structures and microstructures of AlN $(11\overline 2 0)$ /GaN $(11\overline 2 0)$ epitaxial films on just-cut and ±4° off-cut Al₂O₃ $(1\overline 1 02)$ substrates grown by metal organic chemical vapor deposition (MOCVD) are investigated using high-resolution X-ray diffractometry and transmission electron microscopy, and are compared with those of AlN $(11\overline 2 0)$ film on +4° off-cut Al₂O₃ $(1\overline 1 02)$ substrate. In the AlN/Al₂O₃(+4° off-cut) film and the AlN/GaN/Al₂O₃ (just-cut, ?4° off-cut) films, cracks parallel to the $[1\overline 1 00]$ _AlN direction and perpendicular to the interfaces of the films and the substrates are observed. The AlN/Al₂O₃ and AlN/GaN interfaces exhibit low crystallinity in which moiré fringes are observed. On the other hand, in the AlN/GaN/Al₂O₃(+4° off-cut) film, no cracks form. The GaN layer buffers the lattice mismatch between the AlN film and the Al₂O₃ substrate, and moiré fringes are not observed in the GaN/Al₂O₃ and AlN/GaN interfaces. On the basis of these results, the effects of the interface structures on cracking are discussed.     

Particle processing technology

In recent years, there has been strong demand for the development of novel devices and equipment that support advanced industries including IT/semiconductors, the environment, energy and aerospace along with the achievement of higher efficiency and reduced environmental impact. Many studies have been conducted on the fabrication of innovative inorganic materials with novel individual properties and/or multifunctional properties including electrical, dielectric, thermal, optical, chemical and mechanical properties through the development of particle processing. The fundamental technologies that are key to realizing such materials are (i) the synthesis of nanoparticles with uniform composition and controlled crystallite size, (ii) the arrangement/assembly and controlled dispersion of nanoparticles with controlled particle size, (iii) the precise structural control at all levels from micrometer to nanometer order and (iv) the nanostructural design based on theoretical/experimental studies of the correlation between the local structure and the functions of interest. In particular, it is now understood that the application of an external stimulus, such as magnetic energy, electrical energy and/or stress, to a reaction field is effective in realizing advanced particle processing[1 Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar]3 Sakka Y and Uchikoshi T 2010 KONA Powder Particle J. 28 74 (kona.or.jp/search/28_074.pdf) [Google Scholar]].

This special issue comprises 12 papers including three review papers. Among them, seven papers are concerned with phosphor particles, such as silicon, metals, Si₃N₄-related nitrides, rare-earth oxides, garnet oxides, rare-earth sulfur oxides and rare-earth hydroxides. In these papers, the effects of particle size, morphology, dispersion, surface states, dopant concentration and other factors on the optical properties of phosphor particles and their applications are discussed. These nanoparticles are classified as zero-dimensional materials. Carbon nanotubes (CNT) and graphene are well-known one-dimensional (1D) and two-dimensional (2D) materials, respectively. This special issue also includes two papers on the fabrication of mechanically reliable nanocomposites by dispersing graphene into a ceramic matrix, and on supercapacitors with high energy densities in a Co(OH)₂ system decorated with graphene and carbon nanotubes. As a novel preparation method of oxide films, the fabrication of alumina films with laminated structures by ac anodization is reviewed. Moreover a new type of nanosheet has been fabricated by the exfoliation of layered, ternary transition-metal carbide and nitride compounds, known as Mn 1 Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar]1 Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar]AXn phases (or MAX phases) where M is an early transition metal, such as Ti or Nb, A is an A group element, such as Si or Al, X is carbon and or nitrogen and n 1 Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar]1 Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar]3 Sakka Y and Uchikoshi T 2010 KONA Powder Particle J. 28 74 (kona.or.jp/search/28_074.pdf) [Google Scholar][4] Naguib M, Mashtalir O, Carle J, Presser V, Lu J, Hultman L, Gogotsi Y and Barsoum M W 2012 ACS Nano 6 1322 [Google Scholar]. Among the MAX phases, those containing Mo have been theoretically calculated by first-principles calculations to be a source for obtaining Mo₂C nanosheets with potentially unique properties. As an example of improving bulk ceramic properties, texturing by using a high magnetic field[5] Sakka Y and Suzuki T S 2005 J. Ceram. Soc. Japan 113 26 [Google Scholar] and sintering by the electric current activated/assisted sintering (ECAS) technology[6] Grasso S, Sakka Y and Maizza G 2009 Sci. Technol. Adv. Mater. 10 053001 [Google Scholar] have been demonstrated for ultra-high temperature ceramics with high-temperature strength.

A project on the development of materials and particle processing for the field of environment and energy has been ongoing at the National Institute for Materials Science since April 2011. This project employs various core competence technologies for particle processing such as ion beam irradiation for nanoparticle fabrication[7] Nakao H, Tokonami S, Hamada T, Shiigi H, Nagaoka T, Iwate F and Takeda Y 2012 Nanoscale 4 6814 [Google Scholar], fullerene nanomaterial processing using liquidliquid interface precipitation[8] Miyazawa K and Hotta K 2010 J. Cryst. Growth 312 2764 [Google Scholar], a gas reduction nitridation process to obtain Si₃N₄-based phosphor materials[9] Suehiro T, Xie R and Hirosaki N 2013 Indust. Eng. Chem. Res. 52 7453 [Google Scholar], advanced phosphors via novel processing[10, 11] Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar], ultra-high pressure technology for processing and in situ analysis[12 Kawamura F, Yusa H and Taniguchi T 2012 Appl. Phys. Lett. 100 251910 [Google Scholar], 13] Watanabe K and Taniguchi T 2011 Int. J. Appl. Ceram. Technol. 8 977 [Google Scholar], colloidal processing in a high magnetic field to obtain laminated, textured ceramics[1, Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar] 3, Sakka Y and Uchikoshi T 2010 KONA Powder Particle J. 28 74 (kona.or.jp/search/28_074.pdf) [Google Scholar] 5] Sakka Y and Suzuki T S 2005 J. Ceram. Soc. Japan 113 26 [Google Scholar], the ECAS process for nanostructuring ceramics[6] Grasso S, Sakka Y and Maizza G 2009 Sci. Technol. Adv. Mater. 10 053001 [Google Scholar] and so forth. Here, I would like to introduce some research achievements that are not covered in this special issue.

(1) The evolution of hydrogen by the reaction of fine metal particles such as Al[14] Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar] and Mg[15] Uda M, Okuyama H, Suzuki T S and Sakka Y 2012 Sci. Technol. Adv. Mater. 13 025009 [Google Scholar] with water; the specific surface area and surface modification are important factors.

(2) The realization of new carbon related materials with 1D and 2D structures consisting of fullerenes prepared by liquid liquid interface precipitation: alkaline-doped superconductive nanotubes consisting of fullerenes[16] Takeya H, Kato R, Wakahara T, Miyazawa K, Yamaguchi T, Ozaki T, Okazaki H and Takano Y 2013 Mater. Res. Bull. 48 343 [Google Scholar], application to solar cells of fullerene/cobalt porphyrin hybrid nanosheets[17] Wakahara T, D Angelo P, Miyazawa K, Nemoto Y, Ito O, Tanigaki N, Bradley D D C and Anthopoulos T D 2012 J. Am. Chem. Soc. 134 7204 [Google Scholar], etc.

(3) The fabrication of textured films and bulk materials with excellent functional properties by colloidal processing methods such as slip casting[5] Sakka Y and Suzuki T S 2005 J. Ceram. Soc. Japan 113 26 [Google Scholar], gel casting[18] Wiecinska P, Sakka Y, Suzuki T S, Uchikoshi T, Mizerski T and Szafran M 2013 J. Ceram. Soc. Japan 121 89 [Google Scholar] and electrophoretic deposition[3, Sakka Y and Uchikoshi T 2010 KONA Powder Particle J. 28 74 (kona.or.jp/search/28_074.pdf) [Google Scholar] 19] Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar], in a high magnetic field, and with subsequent heating; examples of such materials include dye-sensitized TiO₂ solar cells, thermoelectric materials and cathode materials for solid state Li-ion batteries and dielectric ceramics.

(4) The fabrication of high-strength and high-toughness MAX phase ceramics[20 Hu C, Sakka Y, Grasso S, Nishimura T, Guo S and Tanaka H 2011 Scr. Mater. 64 765 [Google Scholar], 21] Hu C, Sakka Y, Nishimura T, Guo S, Grasso S and Tanaka H 2011 Sci. Technol. Adv. Mater. 12 044603 [Google Scholar] inspired by the nacreous structure[22] Kakisawa H and Sumitomo T 2011 Sci. Technol. Adv. Mater. 12 064710 [Google Scholar].

(5) The modeling and development of the ECAS process[6] Grasso S, Sakka Y and Maizza G 2009 Sci. Technol. Adv. Mater. 10 053001 [Google Scholar]. This involves two-step pressure application[23] Grasso S, Hu C F, Maizza G, Kim B N and Sakka Y 2011 J. Am. Ceram. Soc. 94 1405 [Google Scholar] and high-pressure application above 400 MPa to fabricate transparent oxides[24 Grasso S, Kim B N, Hu C F, Maizza G and Sakka Y 2010 J. Am. Ceram. Soc. 93 2460 [Google Scholar]26] Kim B-N, Hiraga K, Grasso S, Morita K, Yoshida H, Zhang H and Sakka Y 2012 J. Ceram. Soc. Japan 120 116 [Google Scholar], and rapid heating to obtain dense nanocomposites of ceramic–CNT[27] Estili M, Kawasaki A and Sakka Y 2012 Adv. Mater. 24 4322 [Google Scholar] and diamonds[28] Grasso S, Hu C F, Maizza G and Sakka Y 2012 J. Am. Ceram. Soc. 95 2423 [Google Scholar].

(6) The contraction of ternary phase diagrams for oxide ion conductor systems such as zirconia[29] Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar] and apatite systems[30] Sakka Y 2006 J. Ceram. Soc. Japan 114 371 [Google Scholar], leading to an increased understanding of the stability of such systems and assisting the search for high oxygen ion conductors.     

A note on an industrial strategy for stock management in supply chains: modelling and performance evaluation

An analytic formulation of consignment stock (CS) policy has been proposed in Braglia and Zavanella (2003 Braglia M Zavanella L 2003 An industrial strategy for stock management in Supply Chains: modelling and performance evaluation International Journal of Production Research 2003 41 3793 3808  , International Journal of Production Research, 41, 3793) where an implicit analytical solution is given. In this note it is shown that this solution has properties that enable it to be developed into a completely explicit form, allowing for a joint optimization of all decision variables governing the delivery management.     

Grain boundary motion and grain growth in zinc in a high magnetic field

The motion of grain boundaries in zinc bicrystals (99.995 %) driven by the “magnetic” driving force was measured. An in situ technique for observations and continuous recording the boundary migration was applied. Planar symmetrical and asymmetrical $ \left\langle {10\overline{1} 0} \right\rangle $ tilt grain boundaries with rotation angles in the range between 60° and 90° were studied. The boundary migration was measured in the temperature regime between 330 and 415 °C. The mobility of $ \left\langle {10\overline{1} 0} \right\rangle $ tilt boundaries in zinc and its temperature dependence were found to depend on the misorientation angle and the inclination of the boundary plane. An application of a magnetic field during the annealing of cold rolled (90 %) zinc–1.1 % aluminum alloy sheet specimens substantially affected the texture and microstructure evolution. This effect is attributed to the additional magnetic driving force for grain growth arising due to the magnetic anisotropy of zinc.     

Specific Heat of K_{0.71}Na_{0.29}Fe_2As_2 at Very Low Temperatures

A commercially available calorimeter has been used to investigate the specific heat of a high-quality K $_{0.71}$ Na $_{0.29}$ Fe $_2$ As $_2$ single crystal. The addenda heat capacity of the calorimeter is determined in the temperature range $0.02 \, \mathrm{K} \le T \le 0.54 \, \mathrm{K}$ . The data of the K $_{0.71}$ Na $_{0.29}$ Fe $_2$ As $_2$ crystal imply the presence of a large $T^2$ contribution to the specific heat which gives evidence of $d$ -wave order parameter symmetry in the superconducting state. To improve the measurements, a novel design for a calorimeter with a paramagnetic temperature sensor is presented. It promises a temperature resolution of $\Delta T \approx 0.1 \, \mathrm{\mu K}$ and an addenda heat capacity less than $200 \, \mathrm{pJ/K}$ at $ T < 100 \, \mathrm{mK}$ .     

Effect of Pressure on Deep-Ocean Thermometers

A laboratory experiment was devised and performed to investigate the pressure dependence of Sea-Bird Electronics SBE35 and SBE3 deep-ocean thermometers. The thermometers were mounted in a massive brass comparator together with a calibrated standard platinum resistance thermometer. The measurements were performed in a pressure chamber in the pressure range 0.1 MPa to 60 MPa. The results showed that both the investigated SBE35 and SBE3 thermometers are pressure dependent, with a pressure sensitivity of +41 \(\upmu \)K\(\cdot \)MPa\(^{-1}\) and \(-77\) \(\upmu \)K\(\cdot \)MPa\(^{-1}\), respectively. Nevertheless, the results obtained in only one individual device per model (one SBE35 and one SBE3) cannot be generalized and further investigations of a larger number of devices per model are needed.     

Measuring production yield for processes with multiple quality characteristics

Process yield is an important criterion used in the manufacturing industry for measuring process performance. Methods for measuring yield for processes with single characteristic have been investigated extensively. However, methods for measuring yield for processes with multiple characteristics have been comparatively neglected. In this paper, we develop a generalized yield index, called TS _pk,PC , based on the index S_pk introduced by Boyles (Journal of Quality Technology, 23, 17–26, 1991 Boyles, RA. 1991. The Taguchi capability index. J. Qual. Technol., 23: 17–26. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]) using the principal component analysis (PCA) technique. We obtained a lower confidence bound (LCB) for the true process yield. The proposed method can be used to determine whether a process meets the preset yield requirement, and make reliable decisions. Examples are provided to demonstrate the proposed methodology.     

Is There a Unified Description of Conductivity of Layered Cuprates ?

We present a novel approach to the analysis of the normal state in-plane $\sigma _{ab} $ and out-of-plane σ_c conductivities of anisotropic layered crystals such as oxygen deficient YBa ₂ Cu ₃ O _x . It can be shown that the resistive anisotropy is determined by the ratio of the phase coherence lengths in the respective directions; i.e., $\sigma _{ab} /\sigma _c = \ell _{ab}^2 /\ell _c^2 $ . From the idea that at all doping levels and temperatures T the out-of-plane transport in these crystals is incoherent, follows that $\ell _c $ is T-independent, equal to the spacing $\ell _0 $ between the neighboring bilayers. Thus, the T-dependence of $\ell _{ab} $ is given by the measured anisotropy, and $\sigma _{ab} (\ell _{ab} )$ dependence is obtained by plotting $\sigma _{ab} {\text{ }}vs{\text{ }}\ell = {\text{ (}}\sigma _{ab} /\sigma _c )^{1/2} \ell _0 $ .The analysis of several single crystals of YBa ₂ Cu ₃ O _x (6.35 < x < 6.93) shows that for all of them $\sigma _{ab} (\ell ) $ is described by a universal dependence $\sigma _{ab} /\overline \sigma = f(\ell /\overline \ell ) $ with doping dependent parameters $\overline \sigma {\text{ }}and{\text{ }}\overline \ell $ .