Doing Business with Theory: Communities of Practice in Knowledge Management

We explore how the notion of communities of practice (CoPs) was translated and popularized from its original inception by Lave and Wenger in 1991. We argue that the Institute for Research on Learning (IRL), a spin-off of Xerox PARC, proved instrumental in enrolling CoPs into the knowledge management (KM) discipline. IRL objectified, packaged, and made a business out of CoPs. CoPs in KM are now a formalized process coupled with technological artifacts to build groups of people who effectively share knowledge across boundaries. Drawing from participant observations, archival documents, and interviews with KM practitioners in the aerospace industry as well as key players of IRL, our research seeks to unveil the invisible history that the popularization of a theory can often obscure. We argue that CoPs provide a case study for understanding how abstract concepts in science are strategically and subconsciously reified, or made objects of inquiry, and appropriated by actors. This reification of a “soft” science blurs the line between theory and technology.     

Colorimetric microdetermination of sulphites in foods by use of the modified rankine apparatus. IV.

Summary Detection and determination of traces of sulphites in foods was attempted by use of the modified Rankine apparatus and pararosaniline colorimetry. Replacement of alkaline titration reported previously by pararosaniline colorimetry lowered the absolute detection limit from 30 g (titration method) to 2 g. In view of clean analysis, in the color developing system, 0.1 N-sodium hydroxide was used in place of mercuric chloride solution commonly used as an absorbant of sulphites. In order to prevent oxidative decomposition of sulphites during operation, nitrogen gas was used as carrier instead of air. Dimedone and sodium azide were used for the elimination of aldehydes and nitrites, respecitvely, in the sample, which will disturb the color development of sulphites with pararosaniline-formaldehyde reagents. With this improved method, it was possible to determine the residual sulphites in frozen peeled shrimps, sugared beans and other foods with low sulphite contents accurately.

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Colorimetrische Mikrobestimmung von Sulfiten in Lebensmitteln bei Anwendung der modifizierten IV. Rankine Apparatur

Zusammenfassung Geringe Sulfitmengen in Lebensmitteln (geschälte Garnelen, gezuckerte Bohnen) können colorimetrisch bestimmt werden. Die neuentwickelte Methode beruht auf einer Kombination von colorimetrischer Bestimmung mittels p-Rosanilin und der Bestimmungsmethode nach Rankine. Auf diese Weise lassen sich Gehalte von 2 g noch genau bestimmen. Bei der Farbentwicklung wurde das giftige Quecksilbertetrachlorid durch 0.1 n-NaOH ersetzt, anstelle von Luft Stickstoff als Trägergas verwendet und somit eine Oxydation des Sulfits während der Bestimmung vermieden. Da Nitrit und Aldehyde die Farbentwicklung stören, wurde ihr Einfluß durch Dimedon und Natriumazid ausgeschaltet.

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Studies on the Analyses of Sulphites in Foods (IV)     

Formation of Zirconia Solid Solutions Containing Alumina Prepared by New Preparation Method

In the system ZrO₂–Al₂O₃, a new method for preparing ZrO₂ solid solutions from ZrCl₄ and AlCl₃ using hydrazine monohydrate is investigated. c -ZrO₂ solid solutions containing up to ∼40 mol% Al₂O₃ crystallize at low temperatures from amorphous materials. The formation mechanism is discussed from IR spectral data. The values of the lattice parameter α increase linearly from 0.5072 to 0.5105 nm with increasing Al₂O₃ content. At higher temperatures, transformation of the solid solutions proceeds as follows: c ( SS ) → t ( ss ) → t ( ss ) +α-Al₂O₃→ m +α-Al₂O₃. m -ZrO₂–α-Al₂O₃ composite ceramics are fabricated by hot isostatic pressing for 2 h at 1250°C and 196 MPa. Microstructures and mechanical properties are examined, in connection with increasing Al₂O₃ content.     

Plasma glucagon after total resection of the pancreas in man

Serial measurements of plasma "true glucagon" (PG) and of glucagon-like immunoreactive materials (GLI) were carried out during and after total resection of the pancreas in a 62-year-old man with calcified pancreatitis. The postoperative course of this patient was uneventful and diabetes was well controlled. PG disappeared from the blood within 30 min after resection of the pancreas. In spite of the evidence that no pancreatic tissue was present in the abdomen, PG was detected again in the blood from 18 hr after total pancreatectomy until the ninth postoperative day. However, plasma PG did not rise following infusion of arginine during the fourteenth postoperative week. After an initial decrease, plasma GLI rose abruptly on the second postoperative day and remained elevated thereafter. The fluctuations of plasma PG and GLI were not parallel.     

Texture evolution during hot-rolling and recrystallization in B2-type FeAl, NiAl and CoTi intermetallic compounds

The texture evolution during the hot-rolling and the recrystallization of B2-type Fe–48Al, Ni–50Al and Co–50Ti (expressed by at.%) intermetallic compounds were investigated. By hot-rolling at 973 K, Fe–48Al showed a microstructure with coarse grains elongated along rolling direction, while Ni–50Al and Co–50Ti showed a deformed microstructure featured by the heavily distorted (elongated) grains and/or the deformation bands. The hot-rolling texture of Fe–48Al was composed of {111}<uvw>, while those of Ni–50Al and Co–50Ti were composed of {111}<110> and {111}<112>, respectively. After annealing, the recrystallized grains were preferentially nucleated at the grain boundaries for Fe–48Al, and in the heavily distorted regions or the deformation bands for Ni–50Al and Co–50Ti. The orientations of the recrystallized grains were similar with those of the deformed matrix, especially for Ni–50Al and Co–50Ti. The recrystallization textures were generally more dispersive than the hot-rolling texture. Based on these results, the texture evolution during the hot rolling and the recrystallization of the B2-type intermetallic compounds were discussed.     

Substrate effect on the temperature coefficient of resistance of La0.7Ca0.3MnO3 thin films prepared by metal organic deposition

Epitaxial La_0.7Ca_0.3MnO₃ (LCMO) thin films were successfully prepared by the metal-organic deposition process on various (001) single-crystal substrates: MgO, LaAlO₃ (LAO), SrTiO₃ (STO), and (LaAlO₃)_0.3-(SrAlTaO₆)_0.7 (LSAT). The crystallinity and the epitaxial growth of the LCMO films were characterized by X-ray diffraction (θ − 2θ scans and pole-figure analysis). The temperature dependence of the resistance of the LCMO/LSAT, LCMO/STO and LCMO/LAO films exhibit typical characteristics with a transition from the paramagnetic-insulator state to the ferromagnetic-metallic state at a temperature peak (T _p ) ranging from 258 to 270 K. However, the LCMO/MgO films exhibited a semiconducting behavior without any transition. Based on the R(T) measurement, we calculated the temperature coefficient of resistance (TCR) for a bolometric application and we obtained 22%/K, 10.2%/K and 27.5%/K for the film grown on the LSAT, STO and LAO substrates, respectively. This difference in the TCR properties is related to the strain induced by the lattice mismatch between LCMO and the different substrates.     

Demonstration of 13.56-MHz class-E amplifier using a high-Voltage GaN power-HEMT

A 13.56-MHz class-E amplifier with a high-voltage GaN HEMT as the main switching device is demonstrated to show the possibility of using GaN HEMTs in high-frequency switching power applications such as RF power-supply applications. The 380-V/1.9-A GaN power HEMT was designed and fabricated for high-voltage power-electronics applications. The demonstrated circuit achieved the output power of 13.4 W and the power efficiency of 91% under a drain-peak voltage as high as 330 V. This result shows that high-voltage GaN devices are suitable for high-frequency switching applications under high dc input voltages of over 100 V.     

Study of Superconducting Fault Current Limiter Using Vacuum Interrupter Driven by Electromagnetic Repulsion Force for Commutating Switch

Using a high-temperature superconductor, we constructed and tested a model superconducting fault current limiter (SFCL). The superconductor and the vacuum interrupter as the commutation switch were connected in parallel using a bypass coil. When the fault current flows in this equipment, the superconductor is quenched and the current is transferred to the parallel coil because of the voltage drop in the superconductor. This large current in the parallel coil actuates the magnetic repulsion mechanism of the vacuum interrupter. Due to the opening of the vacuum interrupter, the current in the superconductor is broken. By using this equipment, the current flow time in the superconductor can be easily minimized. On the other hand, the fault current is also easily limited by large reactance of the parallel coil     

Multi-modal Information Integration for Interactive Multi-agent Systems

This paper proposes a multi-agent system that carries out cooperative work. To achieve this, we use Fuzzy Associative Memory Organizing Unit Systems (FAMOUS) and Conceptual Fuzzy Sets (CFS). By using these proposed methods, each agent robot can decide its own behaviour to suit the situation in its environment. We apply this system to an Intelligent Transportation System (ITS) and do simulations.     

Vapor pressure measurement of zn-fe intermetallic compounds

Most galvanized steel sheets are produced by a continuous galvanizing line. Some of the operations include a subsequent heat treatment termed galvannealing to form intermetallic phases on the surface. These galvanizing reactions are essentially regarded as “making intermetallic compounds” in the Fe-Zn-M system. This makes it important to know the thermodynamic properties of the system for any detailed discussion on the formation of these intermetallics; however, experimental difficulties have limited the number of studies. In the present study, two-phase regions of these intermetallics were examined, and the following two-phase mixtures were prepared at 723 K: Fe(α)+Γ, Γ,+Γ₁, Γ₁+δ ₁+ζ. The double cell-type Knudsen mass spectrometer system was developed and employed, in which two sets of Knudsen cells were installed in the same cell holder. The reference material (pure zinc) was placed in one cell and a sample in the other. The cell holder was rotated to the reference and sample positions to measure zinc vapor effused from two cells by a quadrupole mass spectrometer. Material containing the two phases was placed in a Knudsen-type effusion cell and the mass spectrum studied to evaluate the vapor pressure of zinc. The activity of zinc in the intermetallics was determined by comparing the intensity from pure zinc and that from intermetallics. Results for Fe(α)+Γ were 0.46 to 0.48; for Γ+Γ₁, 0.51 to 0.54; for Γ₁+δ ₁, 0.62 to 0.66; and for δ ₁+ζ, 0.80 to 0.83, between the temperatures of 623 and 698 K.