Introducing the concept of “uncertainty in measurement” into domestic metrological practice

There are four options for introducing the uncertainty concept in Russia. Preference is given to the gradual replacement of “error characteristic,” “total mean-square error,” and “confidence limits of error” by the terms “uncertainty,” “combined standard uncertainty,” and “expanded uncertainty,” respectively. The incorrect and widespread perception that “uncertainty in measurement” is an alternative for “error” is pointed out. Translated from Izmeritel'naya Tekhnika, No. 5, pp. 27–28, May, 2000.     

Tuning the stress induced martensitic formation in titanium alloys by alloy design

Two novel titanium alloys, Ti–10V–2Cr–3Al and Ti–10V–1Fe–3Al (wt%), have been designed, fabricated, and tested for their intended stress-induced martensitic (SIM) transformation behavior. The results show that for Ti–10V–1Fe–3Al the triggering stress for SIM transformation is independently affected by the β domain size and β phase stability, when the value of the molybdenum equivalent is higher than ~9. The triggering stress was well predicted using the equations derived separately for the commercial Ti–10V–2Fe–3Al alloy. For samples containing β with a lower molybdenum equivalence value, pre-existing thermal martensite is also present and this was found to have an obstructive effect on SIM transformation. In Ti–10V–2Cr–3Al, the low diffusion speed of Cr caused local gradients in the Cr level for many heat treatments leading even to martensite free zones near former β regions.     

Effect of coherency on coarsening of second-phase precipitates in Cu-base alloys

The effects of matrix/precipitate interface states on coarsening of Co and γ-Fe precipitates in a Cu–4 wt.%Co and a Cu–2 wt.%Fe alloy aged at 500 and 700 °C have been examined by transmission electron microscopy (TEM) observations, electrical resistivity measurements, and length-change measurements. Analyses of TEM images show that the average radius for coherent/semi-coherent transition is 6–12 nm for the Co precipitates and 10–20 nm for the γ-Fe precipitates. The coarsening rates of the Co and γ-Fe precipitates are unchanged by the transitions in coherency of the precipitates. The interface energies γ of coherent Co and γ-Fe precipitates are estimated from data on coarsening alone as 0.15 and 0.27 J m⁻². From length-change measurements of the Cu–Co and Cu–Fe alloys during aging, the estimates of the isotropic misfit strains of Co and γ-Fe precipitates are −0.018 and −0.016 for the coherent interfaces and −0.013 and −0.012 for the semi-coherent interfaces. Free energy analyses for the coarsening of Co and γ-Fe precipitates reveal that the values of γ of semi-coherent Cu/Co and Cu/γ-Fe interfaces are 0.24 and 0.34 J m⁻².     

Subcritical crack growth and power law exponent of Y–Si–Al–O(–N) glasses in aqueous environment

The subcritical crack growth resistance in water of a Y–Si–Al–O and Y–Si–Al–O–N glasses has been investigated with three point bending experiments. It has been shown that the SCG behaviour of the Y–Si–Al–O–N glass is superior to that of the Y–Si–Al–O glass. This is reflected by the power law exponent n which is 21 for the Y–Si–Al–O glass and 63 for the Y–Si–Al–O–N glass. Mechanistic implications of these observations are discussed.     

Microstructure and corrosion properties of as sub-rapid solidification Mg–Zn–Y–Nd alloy in dynamic simulated body fluid for vascular stent application

Magnesium alloy stent has been employed in animal and clinical experiment in recent years. It has been verified to be biocompatible and degradable due to corrosion after being implanted into blood vessel. Mg–Y–Gd–Nd alloy is usually used to construct an absorbable magnesium alloy stent. However, the corrosion resistant of as cast Mg–Y–Gd–Nd alloy is poor relatively and the control of corrosion rate is difficult. Aiming at the requirement of endovascular stent in clinic, a new biomedical Mg–Zn–Y–Nd alloy with low Zn and Y content (Zn/Y atom ratio 6) was designed, which exists quasicrystals to improve its corrosion resistance. Additionally, sub-rapid solidification processing was applied for preparation of corrosion-resisting Mg–Zn–Y–Nd and Mg–Y–Gd–Nd alloys. Compared with the as cast sample, the corrosion behavior of alloys in dynamic simulated body fluid (SBF) (the speed of body fluid: 16 ml/800 ml min⁻¹) was investigated. The results show that as sub-rapid solidification Mg–Zn–Y–Nd alloy has the better corrosion resistance in dynamic SBF due to grain refinement and fine dispersion distribution of the quasicrystals and intermetallic compounds in α-Mg matrix. In the as cast sample, both Mg–Zn–Y–Nd and Mg–Y–Gd–Nd alloys exhibit poor corrosion resistance. Mg–Zn–Y–Nd alloy by sub-rapid solidification processing provides excellent corrosion resistance in dynamic SBF, which open a new window for biomedical materials design, especially for vascular stent application.     

Isotopic Composition of Water Used in Triple-Point Cells

Isotopic analysis of the water used in KRISS triple point of water (TPW) cells was performed by three separate laboratories. The δD and δ ¹⁸O isotopic composition of six ampoules, made from two TPW cells, were analyzed by isotope ratio mass spectrometers. The analysis data showed that δD and δ ¹⁸O were − 62.17‰ and − 9.41‰ for the KRISS-2002-Jan cell, and − 36.42‰ and − 4.08‰ for the KRISS-2005-Jun cell. The temperature deviation of the triple point of water for these cells calculated from Kiyosawa’s data and the definition of the TPW were + 45.07μK for the KRISS-2002-Jan cell, and + 25.49μK for the KRISS-2005-Jun cell. The KRISS TPW temperature was + 92μK higher than the CCT-K7 KCRV after correcting for the deviation of the isotopic composition from Vienna Standard Mean Ocean Water.     

Mechanical properties of rapidly solidified ribbons of some AI–Si based alloys

Continuous uniform ribbons of Al–16 Si, Al–12.5 Si–1 Ni and Al–12.5 Si–1 Mg were prepared by melt spinning. Microhardness was measured. The as-melt spun values were 1280, 1370 and 1500 MN m-2 which relax on thermal ageing to 700, 700 and 800 MN m-2 for Al–16 Si, Al–Si–Ni and Al–Si–Mg, respectively. The hardness values of the melt spun ribbons are higher than the as-cast rods from which the ribbons were produced by a factor ranging from 1.8–2.2 times. Tensile testing at room temperature shows that the load–elongation curves are linear with a change of slope occurring in some of the specimens. These curves also show serrations in the case of as-melt spun and the intermediately annealed Al–Si specimens, while no serration was observed in the fully annealed samples. No serration was observed in the Al–Si–Ni and Al–Si–Mg alloys. UTS values were 420, 270 and 100 MN m-2 for Al–16 Si, Al–Si–Ni and Al–Si–Mg, respectively. These values show that the rapid solidification process improved the tensile properties significantly in Al–16 Si and Al–Si–Ni alloys while no significant improvement can be detected for Al–Si–Mg alloy. A discussion is given on hardness relaxation and tensile testing results in terms of silicon precipitation. This revised version was published online in November 2006 with corrections to the Cover Date.     

Study of the dielectric parameters of aluminium ore bauxite of Mainpat area of Chhattisgarh at X-band frequency

A simple method for measuring the dielectric parameter of materials in the form of powders at microwave frequencies is suggested. Measurement of the permittivity ε′ and ge″ at 9·967 GHz on powder samples of the aluminum ore bauxite gives interesting results. It is found that ε′ and ε″ increases with packing densities (δ ). Further ε′ and ε″ also depend upon the percentage of Al₂O₃. These results show that the values of ε′ and ε″ can be used to set certain basic values for minability of the ore for a particular sample. Conductivities (σ) and relaxation (τ) are also calculated in the present studies     

The Internet: a Paradigmatic Rupture in Cumulative Telecom Evolution

The paper investigates the impact the Internet may have in theevolution of telecommunications networks. First, we show whythe Internet, emerging from a different cognitive perceptionof the data communication problem, has led to a new networkarchitecture based on: (i) the distribution of the ‘networkintelligence’ to the user equipment; (ii) the very cost-effective‘statistical sharing’ of the network resources (i.e. getting the whole bandwidth of the network for short periodsof time); (iii) the establishment of an Internet Protocol (IP)‘gateway’ facilitating interoperability betweenheterogeneous infrastructure facilities—instead of theoperator—controlled homogeneity of the telecom networks;and (iv) an ‘adaptative’ way for open standards—setting.Second, we suggest that two technological trajectories (telecom—‘creative accumulation’ and Internet—‘creativedestruction’) should dynamically co-exist henceforth andcompete for market shares—possibly during later evolutionarystages generating relatively different national or even localized(e. g. local providers) trajectories of evolution (with differinginterfaces and standards). Furthermore, we explore the questionof whether the Internet’s interoperability model may bea useful policy paradigm for future information infrastructures,and we start to discuss the implications of requisite interoperabilityon the comunications industry‘s structure itself. Overall,our preliminary observations raise questions about the possibilitiesof two ‘technological trajectories’ co-existing,and the relationship between the interoperability and learningconditions in the network industries.     

On convergence of fisher informations in continuous models with quantized observations

Continuous location models with real observations and well defined Fisher information are considered and reduction of the Fisher information due to quantizations of the observation space intom intervals is studied. In fact, generalized Fisher informations of orders α≥1 are considered where α=2 corresponds to the classical Fisher information. By an example it is argued that in some models the information of order α=2 is infinite while the informations of some orders α↮2 are finite. Among the studied problems is the existence of optimal quantizations which maximize the reduced information for fixedm and α≥1 and the construction of simple and practically applicable quantizations for which the reduction converges to zero whenm→∞, uniformly for all α≥1. The rate of this convergence is estimated for all α≥1 and directly evaluated for α=1 and α=2. For special models the reductions are directly evaluated form=1.2,… either analytically or numerically. Supported by the ASCR grant A1075101 as well as BMF 2003-04820     

Adhesion of PE modified by capacitively coupled radio frequency plasma-induced graft polymerization of glycidyl methacrylate

A graft polymerization of glycidyl methacrylate (GMA) on the pretreated polyethylene (PE) sheet samples by oxygen capacitively coupled radio frequency (RF) plasma was carried out to improve the adhesive properties of PE. The PE samples were treated with a RF power of 200W for a treatment time of 40s and then exposed to an oxygen atmosphere for a saturation time of 10min. The grafting of the plasma pretreated PE performed in an aqueous GMA solution with the monomer concentration from 20vol.% to 100vol.% at a temperature from 20°C to 90°C for a reaction period up to 50h. The optimum wettability of the graft polymerized PE surface with the concentration of 40vol.% at the temperature of 70°C and for the time of 24h was obtained as the static contact angle decreased from 104.2° for the original PE to 67.6° for the graft polymerized. After the graft polymerization, a strong absorption peak of C―O bonding was shown at 1050cm⁻¹ in Fourier transform infrared spectrum, indicating an introduction of epoxy groups on the graft polymerized surface. Correspondingly, the surface roughness (Ra) increased from 0.137μm for the original PE to 1.660μm for the graft polymerized. The maximal lap adhesive strength of the graft polymerized PE samples lapped using a mixture of epoxy resin and curing agent was achieved to about 160N·cm⁻². The fractured surfaces by tearing of the PE sheet matrix were observed on the tensioned PE samples due to the higher adhesive strength than that of the PE matrix.     

Methods of improving the high-tempera ture strength and corrosion resistance of vanadium and certain alloys used in reactors

We present new evidence for the high-temperature strength of vanadium and low-alloyed (up to 15 at.%) vanadium-based alloys under conditions of prolonged (up to 5000 h) high-temperature (973–1173 K) exposure to vacuum, helium, lithium and sodium melts, modeling reactor heat-transport media (10 Pa). The kinetics of phase transformations in alloys of the systems V−Zr−C, V−Nb−Zr−C, V−Mo−Zr−C, and V−Ti−O in the process of prolonged aging under stress is analyzed. It is established that the process of pre-decay of a solid solution has many stages and is intensified by the action of stresses. The corresponding isothermal diagrams of the decay of VTsU (V−Zr−C) alloy are constructed. We give recommendations as to the choice of alloying elements with the aim of enhancing the high-temperature strength of vanadium and vanadium alloys used for reactors. New alloys developed on the basis of the systems V−Ti−O, V−Nb−Zr, V−Ta−Hf, V−Cr−Sc, and V−Cr−Nd and a new method of hardening thermochemical treatment of vanadium-titanium alloys with the use of oxygen from air have found application in pilot-engineering developments for high-temperature nuclear power plants. Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 35, No. 3, pp. 91–104, May–June, 1999.     

Evaluation of cyclic elastoplastic strains near notches

On the basis of direct measurements of the opening displacements of notch contours, we develop an experimental-numerical procedure for the evaluation of the range of local elastoplastic strain Δε_τ. The experimental values of Δε_τ are compared with the data of numerical calculations performed by using formulas known from the literature (Δε). It is shown that, for Δε_τ(Δε)<2%, the experimental and theoretical values are in good agreement but only in the case where the gradients of strains near the tips of the notches are taken into account. For Δε_τ>2%, the theoretical values of Δε are higher than experimental Δε_τ and the smaller the radius of the notch ρ, the greater the difference between these values. Therefore, it reasonable to use the experimentally evaluated and approved values of the parameter Δε_τ. Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 33, No. 2, pp. 62–72, March–April, 1997.     

Advances in the mechanism of cleavage fracture of low alloy steel at low temperature. Part II: Fracture model

The authors discuss in detail the existing cleavage fracture model including the physical model and the statistical model. Based on the discovery that a minimum distance for initiating the cleavage fracture was revealed to have a definite physical meaning, that the stress triaxiality reaches the critical value Tc at this distance instead of that the presence of an eligible carbide crack within this distance is assured; a combined criterion for cleavage fracture, i.e. a critical plastic strain (εp ≥ εpc) for initiating a crack nucleus, a critical stress triaxiality (σ m/σ ≥ Tc) for preventing it from blunting and a critical normal stress (σyy ≥ σ) for its propagation has been proposed to substitute for the criterion of σyy ≥ σ over a ‘characteristic distance’ suggested by the RKR model. With regard to the statistical model the authors suggested that it is not necessary to describe the fracture stress distribution by Weibull function. The fracture probability at a given applied load was modified by multiplying a ‘remaining probability’ taking account of the effect of the preceding loading process. The authors also discuss the mechanism of transition from a fibrous to a cleavage crack within the toughness transition temperature range. This revised version was published online in August 2006 with corrections to the Cover Date.     

A simple method for evaluating the maximum slip of anchorages

The analytical solutions to the bond problem for monotonically increasing loads are developed for a monomial exponential local bond stress-slip relationship (law) – “exact solution” –, a linear local law – “proposed solution” – and a constant bond stress distribution, such as that recommended by the Eurocode. The three solutions are thoroughly developed for the pull-out of a bar embedded in a cylindrical element, with longitudinal concrete in tension. For short anchorages, which undergo a rigid motion and whose “exact solution” requires a complex iterative procedure, the “proposed solution” explicitly provides very accurate bond stress distributions. On the basis of this accuracy, an approximate expression for the slip distribution is derived. The proposed approximate solution is the first one providing a direct slip expression for short anchorages. Approximate explicit expressions for the maximum bond stress and the maximum slip are also given. The comparison between the maximum slip values measured during experimental tests and the corresponding values obtained from the proposed approximate expression demonstrates the accuracy of the latter.     

Formation of strain-induced martensite in chromium–nickel steels of the austenitic class

We investigate the formation of the first portions of strain-induced martensite in plastic uniaxial compression of 12Kh18N10T and 12Kh18N9T steels in which δ-ferrite is absent and present, respectively, in the initial state. The true deformation martensitic points ε _s are experimentally determined. It is established that, in 12Kh18N10T steel, there exist one-phase (A) and two-phase (A + M) states for ε < ε _s and ε > ε _s , respectively, whereas, in 12Kh18N9T steel, there exist two-phase (A + F) and three-phase (A + F + M) states for ε < ε _s and ε > ε _s , respectively. The effect of increase in the magnetization of paramagnetic austenite before the formation of strain-induced martensite is detected.     

Liquid–solid interfacial reactions of Sn–Ag and Sn–Ag–In solders with Cu under bump metallization

Intermetallic compounds formed during the liquid–solid interfacial reaction of Sn–Ag and Sn–Ag–In solder bumps on Cu under bump metallization at temperatures ranging from 240 to 300 °C were investigated. Two types of intermetallic compounds layer, η Cu₆Sn₅ type and ε Cu₃Sn type, were formed between solder and Cu. It was found that indium addition was effective in suppressing the formation of large Ag₃Sn plate in Sn–Ag solder. During interfacial reaction, Cu consumption rate was mainly influenced by superheat of solder, contact area between solder and Cu and morphology of intermetallic compounds. The growth of η intermetallic compounds was governed by a kinetic relation: ΔX = tⁿ, where the exponent n values for Sn–Ag/Cu and Sn–Ag–In/Cu samples at 240 °C were 0.35 ± 0.01 and 0.34 ± 0.02, respectively. The n values increased with reaction temperature, and it was higher for Sn–Ag/Cu than that for Sn–Ag–In/Cu sample at the same temperature. After Cu was exhausted, ε intermetallic compound was converted to η intermetallic compound. The mechanisms for such growth of interfacial intermetallic compounds during the liquid–solid reaction were investigated.     

Nonlinear electrical properties and aging characteristics of (NiO, MgO, Cr2O3)-doped Zn-Pr-Co-R (R = Y, Er) oxide-based varistors

The electrical properties and stability of the varistors, which composed of (NiO, MgO, Cr₂O₃)-doped Zn-Pr-Co-R (Y, Er) oxide-based ceramics, were investigated for different additives. The breakdown voltage of the varistors increased in order of NiO→undoped→MgO→Cr₂O₃: 1200→1551→1691→1959 V/cm for ZPCY system and undoped→NiO→MgO→Cr₂O₃: 1024→1041→1500→1668 V/cm for ZPCE system, respectively. The nonlinear coefficient value increased in order of undoped→NiO→MgO→Cr₂O₃: 21→25→38→50 in ZPCY system and NiO→undoped→MgO→Cr₂O₃: 27→32→35→38 in ZPCE system, respectively. In ZPCY and ZPCE systems, the Cr₂O₃-additives most greatly improved the nonlinear properties. In Cr₂O₃-doped system, ZPCY system exhibited higher nonlinear properties than that of ZPCE system. The stability against d.c. accelerated aging stress was higher in Cr₂O₃-additives than in NiO- and MgO-additives for ZPCY system and was higher in NiO-additives than in MgO- and Cr₂O₃-additives for ZPCE system.     

Ethical motivations for green business and engineering

Corporate references to “sustainability” and the operative process of “green business” have become almost commonplace over the past decade. Companies not only seek to comply with environmental regulations, but many have discovered that techniques for reducing adverse environmental impact often have positive effects on corporate profitability as well. Such adoptions of green business and engineering practices are morally neutral because the driving forces behind them are legal and economic, but not ethical. In some instances, however, managers and engineers have undertaken green business initiatives with the notion of doing something positive for future humans and for the natural environment. In this paper we discuss the “green” driving forces behind moral decisions regarding the adoption of green engineering and business practices and conclude that most “green engineering” known to the public is simply good business practice. Only when engineering and business begin the “green engineering” program with the aim of reducing adverse impact on health or environment does “green engineering” become morally admirable.     

Influence of microstructure on corrosion behavior of Ti–5%Ta–1.8%Nb alloy

This paper presents the results of a study on the influence of microstructure on the corrosion behavior of a α–β Ti–5%Ta–1.8%Nb alloy—a candidate material for use in high concentrations of boiling nitric acid. The “as cast” alloy had a lamellar structure and showed a corrosion rate of about 1.5 mpy. Thermo-mechanical processing of the cast alloy resulted in a structure of predominantly of equiaxed α with random distribution of fine β particles. This “reference” structure was further modified employing different heat treatments similar to that for commercial titanium alloys such as mill annealing, solution treatment and aging or over aging treatments. Corrosion rates evaluated in boiling nitric acid in the liquid, vapor and condensate phases, showed low values ∼1 mpy. Of these, the lowest corrosion rate (∼0.03 mpy) was exhibited by the structure with minimum amount of β phase, distributed in an equiaxed α matrix. This structure was obtained by aging of the solution treated “reference” alloy. Hence, solution treatment high in the α + β phase field followed by aging at a temperature low in the α + β phase field has been identified as the optimum treatment to obtain a microstructure with superior corrosion resistance.