‘Open-loop’ tracking interferometer for machine tool volumetric error measurement—Two-dimensional case

The tracking interferometer, or the laser tracker, is a laser interferometer with a steering mechanism to regulate the laser beam direction to follow a retroreflector (“target”). Applying the multilateration principle, it measures the target's three-dimensional position at an arbitrary location in the workspace. Its application to the volumetric accuracy measurement for coordinate measurement machines or machine tools has been long studied. In this paper, we propose the ‘open-loop’ tracking interferometer, where the laser beam is regulated toward the command target position. This eliminates the automated tracking mechanism and thus may significantly reduce the manufacturing cost of conventional tracking interferometers. The objective of this paper is to validate this ‘open-loop’ tracking interferometer concept by investigating its measurement uncertainty both experimentally and analytically. To simplify the problem, this paper focuses on the measurement of the target's two-dimensional position by using a single-axis ‘open-loop’ tracking interferometer prototype.     

Effect of Silicate Anion Structure on Fixation of Chloride Ions by Calcium Silicate Hydrates

Calcium silicate hydrates, CaO–SiO₂-H₂O (C-S-H), were studied as a chloride fixation material. C-S-H of two different CaO/SiO₂ ratios were synthesized and burned with calcium chloride in a temperature range from 600° to 1000°C. Minerals with a chemical composition of CaO·SiO₂·CaCl₂ and 9CaO·6SiO₂·CaCl₂ were identified by X-ray diffraction analysis. Comparing the diffraction intensity, it was found that the most efficient chloride fixation was attained when burned at 800°C. Changes in the morphology of silicate anion associated with burning and fixation of the chloride were studied in terms of chloride fixation capability using the trimethylsililation technique. It was confirmed that some silicate anions formed a glassy infinite chain where the chloride ions were fixed as a solid solution.     

Effect of Alloying Elements on Microstructure,Martensitic Transformation and Mechanical Properties of Ni-Mn Based Alloys

The microstructural features,shape memory behavior and mechanical properties of Ni-Mn based alloys were investigated by dierential scanning calorimetry(DSC),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and thermal cycling test under various stresses.The transformation temperatures shifted toward lower temperatures when adding a third element into the Ni-Mn system.The addition of 10 at. pct Fe increased considerably the mechanical properties exhibiting still high transformation temp...     

A kinetic analysis of the effects of beta-phenylethylamine on the concentrations of dopamine and its metabolites in the rat striatum

The purpose of this investigation was to determine whether the increase in the dopamine (DA) concentration in the rat striatum after a rapid iv injection of beta-phenylethylamine (PEA) can be quantitatively explained by the alteration of the striatum PEA concentration using a constructed DA metabolism model and to examine whether the time courses of the striatum DA metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) concentration can be described by this DA metabolism model. The time courses of PEA concentration in plasma and the striatum were determined by gas chromatography-mass spectrometry. The plasma PEA concentration was described by a two-compartment model with nonlinear elimination kinetics. The striatum PEA concentration was about 10 times higher than the plasma PEA concentration. The time course of the striatum PEA concentration was described by a diffusion-limited model including a Michaelis-Menten type transport system from plasma to the striatum and nonlinear elimination from the striatum. The DA concentration in the striatum increased immediately after PEA injection. In contrast, the DOPAC concentration in the striatum decreased immediately. HVA concentration in the striatum increased gradually. Assuming that the enhancement of DA concentration in the striatum after PEA injection is caused by the competitive inhibition of PEA on the reuptake of DA into DA neuronal terminals (and the metabolism from DA to DOPAC is then competitively inhibited by PEA in the DA neuronal terminals), the relationship between the enhancement of DA concentration and PEA concentration in the striatum was analyzed using a constructed DA metabolism model. The enhancement of the DA concentration in the striatum was described quantitatively by this model. Thus, it was clarified that a quantitative relationship between PEA concentration and the enhancement of DA concentration in the striatum is present after PEA injection. However, the time courses of the striatum DOPAC (lower dose) and HVA (time delay) concentrations could not be described by this model. These results indicated that other factors might be necessary to explain the time courses of the DOPAC and HVA concentrations in the striatum after PEA injection, such as the separate evaluation of the effect of PEA on the reuptake of DA into DA neuronal terminals and on the monoamine oxidase-B (MAO-B) activity in the DA neuronal terminals, and the metabolic pathway from DOPAC to HVA.     

Cautious transaction schedulers for database concurrency control

Cautious schedulers, which never resort to rollbacks for the purpose of concurrency control, are investigated. In particular, cautious schedulers for classes WW consisting of schedules serializable under the write-write constraints, and WRW, a superclass of W, are considered. The cautious WW-scheduler has a number of nice properties, one of which is the existence of a polynomial-time scheduling algorithm. Since cautious WRW-scheduling is, in general, NP-complete, some restrictions are introduced which allow polynomial-time scheduling. All of these cautious schedulers are based on the assumption that transaction predeclare their read and write sets on arrival. Anomalies which occur when transaction modify their read sets or write sets during execution are discussed and countermeasures are proposed     

Origin of Ordering Coupled Tweed Microstructures in Alloys with Large Atomic Size Factors

A theoretical study is developed on the evolution and mechanism of an ordering coupled phase separation, and on the origin of a resultant tweed microstructure. It is found that long-range elastic interaction among atoms with different atomic sizes plays a key role in the phase sep aration, and that the evolution of the phase separation is very similar to that Of conventional spinodal decomposition except that the separation is dependent on an elastic interaction order ing (EIO). This "EIO coupled spinodal decomposition" is shown to exhibit a periodical or tweed microstructure being accompanied by an EIO. It is also found that a large atomic size factor yields a large positive contribution of EIO to spinodal decomposition. Generally it is thermodynamically and kinetically favorable for the EIO to precede the onset of spinodal decomposition,though the former is not separable from the latter as a whole. We suggest that an initially disordered solid solution undergoes an EIO first, and then the partially ordered solid solution starts to decompose via a spinodal mechanism. Solute-enriched regions increase their degree of order along with an increase in solute content, and solute-depleted regions decrease their degree of order together with a decrease of solute content. The final microstructure is characterized by a periodical array of highly ordered solute-enriched regions and nearly disordered solute-depleted regions. The notion of EIO coupled spinodal decomposition is in general agreement with the transformation behaviour of a large number of alloy systems.     

Elastic Energy and Elastic Interaction Ordering of Binary Solid Solutions

A theory in the framework of continuum elasticity has been developed to calculate the totalcontribution of "atomic size effect" or "strain energy effect" to free energy of binary solidsolutions. It is found that elastic free energy consists of two parts f elastic self energy (ESE),and elastic interaction energy(EIE). The former is a function of composition alone, the latter isalso a function of atomic configuration. Minimization of total elastic free energy with respect toatomic arrangement resuIts in an ordered arrangement of atoms, which is caIIed elastic interactionordering (EIO), as it originates from elastic interaction among atoms. EIO is a kind of localordering within a "characteristic range", and it is found to be important in determining the Stateof solid solutions and structures of superlattices. The present theory also gives good explanationto the coexistence of ordering and decomposition which can not be understood in conventionaltheories.     

A personal perspective on problem solving by general purpose solvers

To solve the problems that abound in real‐world applications, we are proposing an approach of using general‐purpose solvers, as we cannot afford to develop special‐purpose algorithms for all individual problems. The existing general‐purpose solvers such as linear programming and integer programming are very useful but not sufficient. To improve the situation, we have developed solvers for other standard problems such as the constraint satisfaction problem and the resource‐constrained project scheduling problem among others. In this article, we describe why general‐purpose solvers are needed, what kinds of solvers we considered, how they were developed and where they have been applied.