bluuebunny/crossref_metadata_2025 huggingface dataset:
The Rossmann Fourier autoindexing algorithm in MOSFLM
Authors: Powell Harold R.
Published: July 2002

The fast Fourier transform (FFT) autoindexing routines written by the Rossmann group at Purdue University have been incorporated in MOSFLM, providing a rapid and reliable method of indexing oscillation images. This is a procedure which extracts direct-space information about the unit cell from the FFT. The method and its implementation in MOSFLM are discussed.
Experiences and expectations of a novel X-ray microsource with focusing mirror. I
Authors: Bloomer A. C. , Arndt U. W.
Published: July 2002

Data are presented from a novel microfocus X-ray generator installed with a choice of ellipsoidal specularly reflecting mirrors. Diffraction data from proteins show the useful flux from this low-power device to be approaching equivalence with that from many far more powerful generators. Intensity measurements show that for small crystals the brilliance is now restricted by the performance of the mirror, which appears to be limited by imperfections in the figure of its surface rather than by a low reflectivity. Suitable choices of ellipsoidal mirror enable the size and divergence of the X-ray beam to be altered readily to match the different requirements of successive samples and appropriate designs are proposed. Alternative types of mirror are expected to be advantageous, especially for the smallest crystals. For crystals of sizes 300 µm or less, which need a small well collimated beam with low divergence, the output from this X-ray tube running at 24 W provides a usable flux similar to that available from rotating-anode generators. The relative performance of this tube and mirror combination becomes increasingly advantageous with the study of ever-smaller crystals.
Expression, purification, crystallization and preliminary X-ray analysis of Escherichia coli argininosuccinate synthetase
Authors: Lemke Chris , Yeung Melissa , Howell P. Lynne
Published: July 2002

A recombinant form of Escherichia coli argininosuccinate synthetase with a C-terminal polyhistidine affinity tag has been expressed, purified and subsequently crystallized using the hanging-drop vapour-diffusion technique. The crystals grow as large rectangular chunks with unit-cell dimensions a = 79.70, b = 105.84, c = 127.33 Å, α = β = γ = 90°. The crystals exhibit the symmetry of space group I222 and diffract to a minimum d-spacing of 1.6 Å at station X8C of the National Synchrotron Light Source, Brookhaven National Laboratory. On the basis of density calculations, one monomer of this homotetrameric protein is predicted per asymmetric unit (Matthews coefficient Vm
= 2.69 Å3 Da−1).
Crystallization and preliminary analysis of bovine adenosine deaminase
Authors: Kinoshita Takayoshi , Nishio Nobuya , Sato Akihiro , Murata Masayoshi
Published: July 2002

Adenosine deaminase (ADA) from bovine intestine was crystallized with purine riboside by vapour diffusion using ammonium sulfate as precipitant. The crystals are tetragonal and have unit-cell parameters a = b = 80.03, c = 141.68 Å. They belong to space group P41212 or P43212 and diffract to at least 2.0 Å resolution. The structure is being solved by molecular replacement.
Comparing anisotropic displacement parameters in protein structures
Authors: Merritt Ethan A.
Published: July 2002

The increasingly widespread use of synchrotron-radiation sources and cryo-preparation of samples in macromolecular crystallography has led to a dramatic increase in the number of macromolecular structures determined at atomic or near-atomic resolution. This permits expansion of the structural model to include anisotropic displacement parameters Uij
for individual atoms. In order to explore the physical significance of these parameters in protein structures, it is useful to be able to compare quantitatively the electron-density distribution described by the refined Uij
values associated with corresponding crystallographically independent atoms. This paper presents the derivation of an easily calculated correlation coefficient in real space between two atoms modeled with anisotropic displacement parameters. This measure is used to investigate the degree of similarity between chemically equivalent but crystallographically independent atoms in the set of protein structural models currently available from the Protein Data Bank.
Crystallization and preliminary X-ray diffraction studies of human epidermal growth factor
Authors: Chai Ji-Jie , Li Ming , Huang Bing-Ren , Luo Yu , Luo Ming , Bi Ru-Chang , He Cun-Heng
Published: July 2002

Human epidermal growth factor (hEGF), a 6.2 kDa protein of 53 amino acids with three internal disulfide bridges, has been crystallized by the hanging-drop method. hEGF crystallizes in space group P3121 (or P3221) using MgCl2 as precipitant, with unit-cell parameters a = b = 61.4, c = 87.0 Å. Another type of crystal, obtained using NaCl as precipitant, belongs to a tetragonal point group and has unit-cell dimensions a = b = 102.5, c = 166.6 Å. The trigonal crystals with the smaller unit cell diffract X-rays better and a native data set from a single crystal has been collected to 3.0 Å resolution.
Crystallization and preliminary diffraction studies of a truncated form of a novel protease from spores of Bacillus megaterium
Authors: Ponnuraj Karthe , Kelly Stephen , Nessi Claudio , Setlow Peter , Jedrzejas Mark J.
Published: July 2002

During germination of spores of Bacillus species, a novel protease termed GPR initiates the degradation of a group of small acid-soluble spore proteins which protect the dormant spore's DNA from damage. Trypsin digestion of the zymogen of B. megaterium GPR removes ∼15 kDa from the C-terminal end of the 46 kDa zymogen subunit, leaving a 30 kDa subunit. Single crystals of this truncated form of GPR have been obtained by the vapor-diffusion method using PEG 4000 as a precipitating agent. The crystals belong to the monoclinic space group P21, with unit-cell parameters a = 67.99, b = 105.34, c = 108.63 Å, β = 95.68°. The cryofrozen crystals diffract X-rays to about 3.3 Å using synchrotron radiation.
Feasibility and review of anomalous X-ray diffraction at long wavelengths in materials research and protein crystallography
Authors: Kahn Richard , Carpentier Philippe , Berthet-Colominas Carmen , Capitan Maria , Chesne Marie-Laure , Fanchon Eric , Lequien Stéphane , Thiaudière Dominique , Vicat Jean , Zielinski Piotr , Stuhrmann Heinrich
Published: July 2002

The feasibility and a review of progress in the long-wavelengths anomalous dispersion technique is given in the context of the development of beamline ID1 of the ESRF for such studies. First experiments on this beamline and their analyses are described. The first study reports on the use of uranium which exhibits an unusually strong anomalous dispersion at its M
V absorption edge (λ
M
V
= 3.5 Å). The anomalous scattering amplitude of uranium with 110 anomalous electrons exceeds the resonance scattering of other strong anomalous scatterers like that of the rare earth ions by a factor of four. The resulting exceptional phasing power of uranium is most attractive in protein crystallography using the MAD method. The anomalous dispersion of a uranium derivative of asparaginyl-tRNA synthetase (hexagonal, a = 124.4 Å, c = 123.4 Å) has been measured at three wavelengths near the M
V edge using beamline ID1 of the ESRF. The present set-up allowed the measurement of 10% of the possible reflections at a resolution of 8 Å. This is mainly due to the low sensitivity of the CCD camera. The second study, involving DAFS experiments at wavelengths near the K-absorption edge of chlorine (λ
K
= 4.4 Å), reports the use of salt crystals which give rise to much stronger intensities of diffraction peaks than those of protein crystals. In the case of a crystal of pentamethylammonium undecachlorodibismuthate (PMACB, orthorhombic, a = 13.00 Å, b = 14.038 Å, c = 15.45 Å), all reflections within the resolution range from 6.4 Å to 3.5 Å and the total scan width of 24° were collected. The crystalline structure of PMACB implies two chemically distinct states of the Cl atom. Consequently, different dispersions near the K-edge of chlorine are expected. The dispersion of the intensity of five Bragg peaks of the PMACB crystal has been measured at 30 wavelengths. The relative success of these preliminary experiments with X-rays of long wavelength shows that the measurement of anomalous X-ray diffraction at wavelengths beyond 3 Å is feasible. Starting from the experience gained in these experiments, an increased efficiency of the instrument ID1 by two to three orders of magnitude will be achieved in this wavelength range. A comparison with different techniques of anomalous diffraction which rely on the use of argon/ethane-filled multiwire chambers and image plates as detectors for wavelengths near the K-edge of sulfur and phosphorus is also given.
Anomalous scattering for small-molecule crystallography
Authors: Helliwell Madeleine
Published: July 2002

Anomalous dispersion techniques in small-molecule crystallography have been used in recent years with the advent of intense tunable X-radiation from synchrotron X-ray sources. By tuning the wavelength of the radiation close to the absorption edges of specific elements, it is possible to identify and distinguish between atoms which are close together in atomic number, even when two or more such atoms occupy a single site. Anomalous dispersion techniques can also be used to distinguish between valence states of different sites of an element by the valence contrast method or to determine the coordination geometry of an atom. In some cases, when the coordination of an atom is asymmetric, the absorption-edge position may depend on the orientation of the crystal. Finally, anomalous dispersion techniques can be used for ab initio structure solution from powder diffraction data. The properties of microporous materials often depend on the incorporation of metal atoms into the framework. Two or more metal atoms close together in atomic number may be incorporated, sometimes occupying a single site. In one study the site of an Ni atom in the aluminophosphate NiAPO was determined by anomalous dispersion techniques and data from the NSLS. Also, the location of the isomorphously substituted cobalt over two crystallographically different zinc sites was determined in the zincophosphate CoZnPO–CZP, in a five-wavelength study using data from ELETTRA.
Iodine L-edge XAFS study of linear polyiodide chains in amylose and α-cyclodextrin
Authors: Konishi Takehisa , Tanaka Wakana , Kawai Takeshi , Fujikawa Takashi
Published: July 2002

We performed iodine L edge XAFS measurements on blue-black amylose-iodine complex to obtain information about the electronic and geometrical structures of polyiodide chain included in amylose helix. Measurements were also carried out on crystalline α-cyclodextrin-iodine complex (α-cyclodextrin)2Cd0.5I5.27H2O, in which the polyiodide chain is known to consist of I5
− unit. It was found that the XANES spectra of these complexes have similar line shapes except for some minor differences, indicating that there are close similarities in the nature of polyiodide chains in these complexes. Besides their similarity, difference in the intensity of the peak at the L1 absorption edge was observed. Its implication for the electronic and geometrical structures is also discussed.
EXAFS analysis of the zinc-binding domain of boar spermatidal transition protein 2
Authors: Kawai Takeshi , Konishi Takehisa , Fujikawa Takashi , Sekine Atushi , Imai Lica F. , Akama Kuniko
Published: July 2002

Boar Spermatidal Transition Protein 2 (TP2; 137 amino acid residues) is supposed to play an important role in initiation of chromatin condensation and cessation of transcriptional activity during mammalian spermiogenesis. Boar TP2 has three potential zinc finger motifs and binds three atoms of zinc per molecule. However the structure of the zinc-binding domain of boar TP2 has not been completely determined. To elucidate the local structure around the zinc atoms of boar TP2, we performed an X-ray absorption fine structure (XAFS) measurement on the zinc-binding domain of TP2(TP2Z)(residues 1-103) in the fluorescence mode. By EXAFS analyses we have demonstrated that each of the three zinc atoms is coordinated by approximately two sulfur and two nitrogen atoms on average. The average Zn-S and Zn-N distances were found to be 2.36 Å and 2.01 Å, respectively. The sulfur and nitrogen atoms are attributed to cysteine and histidine residues, respectively, from comparison of the EXAFS spectra with model compounds ZnS and ZnTPP(zinc(II) tetraphenylporphyrin).
A position-sensitive ionization chamber for XAFS studies at synchrotron sources
Authors: Sato Kazumichi
Published: July 2002

A position-sensitive ionization chamber has been developed with backgammon-type-segmented electrodes. This novel detector possesses a linear range of 8 mm for determining the incident position of the X-ray beam incoming. The position resolution was found to be less than 10 µm, probably close the sub-micrometer region. Owing to its high spatial resolution, the position-sensitive ionization chamber was able to commit that the gradual decrease observed in the X-ray beam intensity at a SPring-8 beamline was mainly due to the spatial variation of the X-ray beam in time. The present work also confirmed the applicability of the novel detector to the accurate monochromator adjustment for experiments using diamond anvil cells.
Solid-state kinetics from time-resolved in situ XAFS investigations: reduction and oxidation of molybdenum oxides
Authors: Ressler T. , Jentoft R. E. , Wienold J. , Timpe O.
Published: July 2002

The reduction of MoO3 with hydrogen was studied by in situ X-ray absorption spectroscopy. The experiments performed focused on elucidating phase composition and evolution with time under isothermal reduction conditions. From temperature programmed experiments short-range structural details about the early stage of the reduction were obtained.
EXAFS as a tool for bond-length determination in the environment of heavy atoms
Authors: Hennig C. , Reich T. , Funke H. , Rossberg A. , Rutsch M. , Bernhard G.
Published: July 2002

Single crystal X-ray diffraction measurements are complicated in the presence of heavy atoms. In these cases the structure factors are mainly influenced by the heavy scatterers and the error in determination of atomic coordinates increases for light atoms. The difficulties grow if the unit cell dimensions or the space group symmetry remain uncertain. If the structure model is similar to the correct structure, it is difficult to find an independent criterion for the accuracy of the bond-length determination. We demonstrate that extended X-ray absorption fine structure (EXAFS) spectroscopy is a useful tool for the investigation of local bond lengths in the environment of heavy atoms.
Development of an in situ polarization-dependent total-reflection fluorescence XAFS measurement system
Authors: Chun Wang-Jae , Tanizawa Yasuhiro , Shido Takafumi , Iwasawa Yasuhiro , Nomura Masaharu , Asakura Kiyotaka
Published: July 2002

An in situ polarization-dependent total-reflection fluorescence X-ray absorption fine structure (PTRF-XAFS) spectroscopy system has been developed, which enables PTRF-XAFS experiments to be performed in three different orientations at various temperatures (273–600 K) and pressures (10−10∼760 torr). The system consists of a measurement chamber and a preparation chamber. The measurement chamber has a high-precision six-axis goniometer and a multi-element solid-state detector. Using a transfer chamber, also operated under ultra-high-vacuum conditions, the sample can be transferred to the measurement chamber from the preparation chamber, which possesses low-energy electron diffraction, Auger electron spectroscopy and X-ray photoelectron spectroscopy facilities, as well as a sputtering gun and an annealing system. The in situ PTRF-EXAFS for Cu species on TiO2 (110) has been measured in three different orientations, revealing anisotropic growth of Cu under the influence of the TiO2 (110) surface.
Element-specific magnetization curves and crossover in Co/Cu/Ni/Cu(001) trilayers studied by XMCD
Authors: Scherz A. , Wilhelm F. , Poulopoulos P. , Wende H. , Baberschke K.
Published: July 2002

We present temperature-dependent measurements via the element-specific XMCD technique for Co/Cu/Ni trilayers for cases where the ordering temperature of Co is lower than the one of Ni. Our work focuses mainly on the influence of the interlayer coupling on the shape of the temperature-dependent magnetization curves of Ni. By selecting 1.3 ML of Co and 4 ML of Ni we get a lower T

C
(Co) ≃ 90 K and a higher T

C
(Ni) ≃ 180 K. The crossing of the M(T) curves leads to a rotation of the remanent magnetization of Ni. A case where the sublayer magnetizations change gradually their angle as a function of the temperature is recorded and attributed to a competition between coupling and anisotropy mechanisms.
Determining crystalline atomic positions using XAFS, a new addition to the UWXAFS analysis package
Authors: Kelly S. D. , Stern E. A. , Ingalls R.
Published: July 2002

XAFS and x-ray diffraction (XRD) are complementary structure determination techniques. The combination of XAFS and XRD can be used to determine the complete crystal structure when diffraction can not be refined. This is often the case at high pressures or high temperatures where there is limited access to the samples and energy dispersive x-ray diffraction is used. A new method to determine the atomic positions within the unit cell using EXAFS data with the programs RUNFIT and MKFIT is described. These programs systematically produce and test models for the XAFS data that are consistent with the diffraction results. The programs were written to solve the structure of two intermediate high pressure phases of AgCl, and are distributed with a working example.
Structural studies of lanthanide(III) complexes with oxydiacetic acid and iminodiacetic acid in aqueous solution by EXAFS
Authors: Narita Hirokazu , Yaita Tsuyoshi , Suzuki Shinichi , Takai Konomi , Tachimori Shoichi , Motohashi Haruhiko
Published: July 2002

The local structure of the trivalent lanthanide (Ln(III)) complexes with oxydiacetic acid (ODA) and iminodiacetic acid (IDA) in aqueous solution was investigated by EXAFS spectroscopy. The coordination number and the bond distance were obtained by the detailed EXAFS analysis. The coordination number of Ln(III) in both the Ln-ODA and -IDA systems decreases from nine for lighter Ln(III) to eight for heavier Ln(III). The bond distances of ether O atoms from Ln(III) in the Ln(ODA)3
3- complexes are shorter than those of N atoms in the Ln(IDA)3
3- ones.
Diffraction anomalous fine structure of forbidden reflection of super-ordered GaInP
Authors: Alagna Lucilla , Turchini Stefano , Prosperi Tommaso
Published: July 2002

We used DAFS to probe super-ordered domains in InGaP/GaAs epitaxial growth. The sample was lattice matched InGaP epitaxially grown on GaAs with a substrate miscut angle of 6 degrees with respect to the (001) direction. InGaP epi-layer exhibited (111)-type alloy ordering, of alternating InP and GaP - like planes and giving rise to a (-5/2,5/2,-5/2) Bragg peak reflection which becomes allowed. Structural data can be extracted, at the same time, for the surroundings of Gallium in the bulk and in the epi-layer from allowed reflections, while the forbidden reflection gives structural details around Gallium in the ordered domains. Difference with the bulk InGaP Fourier transform confirms the symmetry selectivity of chosen reflections for the super-ordered domains.
Variation of XMCD spectrum with temperature at R L
2,3-edges in R3Fe5O12 (R = Gd and Er)
Authors: Kawamura Naomi , Suzuki Motohiro , Maruyama Hiroshi , Ishikawa Testuya
Published: July 2002

The variation of X-ray magnetic circular dichroism (XMCD) with temperature has been measured at R L
2,3-edges in R3Fe5O12 (R = Gd and Er). A drastic change in the spectral profile has been observed at low temperatures. The variation of XMCD peak intensity, corrected by the contribution of Fe with temperature, is in agreement with the magnetization of R sublattice. The results suggest that Fe 3d polarization plays an important role to produce the R L
2,3-edges XMCD spectrum.
Structural properties of Cu-Permalloy under annealing
Authors: Cezar Júlio C. , Knobel Marcelo , Tolentino Helio C. N.
Published: July 2002

We have studied the structure of melt-spun copper-permalloy samples (Cu80Fe4Ni16), annealed at several temperatures up to 873 K by means of EXAFS spectroscopy. The results for iron first neighbor average distance showed a slow decrease for annealing temperatures higher than 673 K. The nickel first neighbor distance had almost no change in the whole temperature range. This behavior is discussed in the light of rich iron cluster formation, and is compared with magnetic measurement results.
Relationship Between Spatial Coherence of Synchrotron Radiation and Emittance
Authors: Takayama Y. , Hatano T. , Miyahara T. , Okamoto W.
Published: July 2002

Analytical calculation of the first-order spatial coherence for the Gaussian beam and the exact numerical calculation for synchrotron radiation are compared in this paper. The approximation of regarding synchrotron radiation as a Gaussian beam is often used to investigate the brightness, the flux and some qualitative properties. Calculations show that synchrotron radiation does not have as high coherence as the Gaussian beam because of the beam profile, the phases of the wave and the polarization. If one can measure the beam size and the spatial coherence of synchrotron radiation, it is possible to determine the total photon beam emittance without any knowledge of the Twiss parameters of the ring.
Ultrahigh-Vacuum Facility for High-Resolution Grazing-Angle X-ray Diffraction at a Vertical Wiggler Source of Synchrotron Radiation
Authors: Sakata O. , Tanaka Y. , Nikolaenko A. M. , Hashizume H.
Published: July 2002

A versatile ultrahigh-vacuum chamber has been designed for grazing-angle X-ray standing-wave and diffraction experiments at the vertical wiggler source of the Photon Factory. Unlike at other sources, the vertically polarized X-rays from the wiggler favour the use of a horizontal scattering geometry. The X-ray chamber is equipped with a hemispherical beryllium window, which allows any scattering angle to be attained and secondary emissions to be measured. The chamber is of a compact design, sitting on a precision rotary table which is rotated for scans. Samples are introduced from a portable vessel. The whole procedure can be performed in a vacuum better than 10−7 Pa. The system has successfully been applied to a grazing-angle X-ray standing-wave experiment, which determined the dimer bond length and the domain structure of Si(001) surfaces deposited with monolayer arsenic.
Present Status and Performance of SPring-8 Front Ends
Authors: Sakurai Y. , Oura M. , Takahashi S. , Hayashi Y. , Aoyagi H. , Shiwaku H. , Kudo T. , Mochizuki T. , Oikawa Y. , Takahasi M. , Yoshii K. , Kitamura H.
Published: July 2002

SPring-8 front ends have a novel structure which makes it easy to rearrange them and exchange the components. The structure has a common support for all the components except X-ray beam-position monitors and lead collimators. The alignment of the common support as well as the components was carried out with an accuracy of 0.25 mm in the vertical and horizontal directions. Replaceable pumping systems have also been placed on the common support and have achieved a vacuum of 2 × 10−8 Pa at the upstream part of the front ends without synchrotron radiation. During the commissioning with synchrotron radiation, the pumping systems displayed good pumping-down characteristics. Commissioning has been successfully performed for four standard in-vacuum X-ray undulators and three bending-magnet-beamline front ends up to July 1997. Measurements of temperature rise show that absorber, pre-slits and XY slits can handle the anticipated maximum heat load at a ring current of 100 mA.
SEDEM, a Software Package for EXAFS Data Extraction and Modelling
Authors: Aberdam Daniel
Published: July 2002

A software package for extended X-ray absorption fine structure (EXAFS) data extraction and modelling, running on DOS- or Windows-operated PCs, is described. This package is written with the aim of giving the user a tool to undertake all steps of data processing and modelling, rather than making use of the most recent programming facilities. However, it remains easy to use, and self-explanatory to those who have already worked with EXAFS. It is divided into two main executable pieces of software. The first one is used to extract the EXAFS k

n
χ(k) function from the data and isolate the shell contributions by Fourier filtering. A tool to sum the spectra before EXAFS extraction is provided. The second one is designed to model the EXAFS spectra or the shell contributions, using amplitude and phase data either from McKale's tables, computed from the FEFF program or extracted from experimental reference spectra. This modelling program allows either an optimization of the simulation by a least-mean-square gradient algorithm, with a statistical evaluation of the result of optimization, or, in the case of a single shell, a direct determination of the four main parameters (neighbour distance and number, energy shift and Debye–Waller factor) by decorrelation of the phase and amplitude. In the presence of anharmonicity, the cumulant expansion of the radial distribution of distances is obtained from the phase and amplitude decorrelation. This package is in use at the Collaborative Research Group on Interfaces (CRG-IF) bending-magnet #32 X-ray line (BM-32) at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France.
X-ray powder diffraction with hybrid semiconductor pixel detectors
Authors: Manolopoulos S. , Bates R. , Bushnell-Wye G. , Campbell M. , Derbyshire G. , Farrow R. , Heijne E. , O'Shea V. , Raine C. , Smith K. M.
Published: July 2002

Semiconductor hybrid pixel detectors, originally developed for particle physics experiments, have been used for an X-ray diffraction experiment on a synchrotron radiation source. The spatial resolution of the intensity peaks in the diffraction patterns of silicon and potassium niobate powder samples was found to be better than that of a scintillator-based system, typically used at present. The two-dimensional position information of the pixel detector enabled multi-peak diffraction patterns to be acquired and clearly resolved without the need for an angle scan with a diffractometer. This trial experiment shows the potential of this technology for high-resolution high-rate diffraction systems.
Tetragonal modification of 1,1,3,3,5,5-hexamethylcyclo-1,3,5-tristannathiane
Authors: Farina Yang , Baba Ibrahim , Othman A. Hamid , Razak Ibrahim Abdul , Fun Hoong-Kun , Ng Seik Weng
Published: July 2002

The space group of the title compound, [Sn3S3(CH3)6], reported asP41, is corrected toP42212.
cis-Aquabis(2,2′-bipyridine-N,N′)[dichromato(2–)-O1]nickel(II)
Authors: Fernández-González Nélida , González-Silgo Cristina , González-Platas Javier , Gili Pedro , Martín-Zarza Pedro
Published: July 2002

The molecular structure of the title compound, [Ni(C10H8N2)2(H2O){Cr2O7}], contains an NiIIatom with a distortedcis-octahedral coordination formed by two chelating bipyridine (bipy) ligands [mean Ni—Nbipy = 2.068 (3) Å], one water molecule [Ni—O = 2.086 (3) Å] and an O atom of the dichromate anion [Ni—O = 2.083 (2) Å]. One of the water H atoms is involved in the intramolecular hydrogen bond with the terminal O atom of the dichromate ligand [O...O 2.743 (5) Å], whereas its second H atom participates in the intermolecular hydrogen bonding [O...O 2.688 (4) Å]; the latter is responsible for the formation of the infinite chains stretching along the polarcaxis of the crystal.
[(1RS,4RS)-5,5,7,13,15,15-Hexamethyl-1,4,8,12-tetraazacyclopentadeca-7,12-diene-N1,N4,N8,N12]nickel(II) diperchlorate
Authors: Curtis Neil F. , Waters Joyce M. , Rickard Clifton E.
Published: July 2002

The title compound, [Ni(C17H34N4)](ClO4)2, has singlet ground-state nickel(II) complex cations in tetrahedrally twisted square-planar coordination by the four N atoms of the 15-membered diamine diimine tetraazamacrocycle and disordered perchlorate anions, linked into molecular clusters by N—H...O hydrogen bonds and weak Ni...O interactions. The cation has approximate twofold symmetry, with bond lengths Ni—Namineof 1.920 (2) and 1.924 (2) Å, and Ni—Nimineof 1.915 (2) and 1.929 (2) Å, andtrans–N—Ni—N angles of 165.1 (1) and 163.4 (1)°, with the shortest Ni...O distance being 3.27 (3) Å.
Manufacturing turbine blisks
Authors: Zhan H. , Zhao W. , Wang G.
Published: July 2002

Various techniques for manufacturing integrally bladed turbine disks (turbine blisks) are described, followed by a discussion of the development trend of turbine blisk manufacture. Analysis shows that powder metallurgy near‐net‐shape hot isostatic pressing will be the focus of future research for turbine blisk blanking, while electrical discharge machining still will be the most competitive technology for turbine blisk finishing.
Towards application of fibre metal laminates in large aircraft
Authors: Vlot A. , Vogelesang L.B. , de Vries T.J.
Published: July 2002

Fibre metal laminates were developed at Delft University during the last two decades as a family of new hybrid materials consisting of bonded thin metal sheets and fibre/adhesive layers. This laminated structure provides the material with excellent fatigue, impact and damage tolerance characteristics and a low density. While the 20 per cent weight reduction was the prime driver behind the development of this new family of materials, it turns out that additional benefits like cost reduction and an improved safety level have become more and more important. The combination of these aspects in one material makes fibre metal laminates a strong candidate material for fuselage skin structures of the new generation of high capacity aircraft. The focus on this application currently leads to industrialization and qualification that makes this material available to the aircraft designer.
Corporate identity and corporate communications: creating a competitive advantage
Authors: Balmer John M.T. , Gray Edmund R.
Published: July 2002

Recent environmental trends are forcing senior managers to give greater import to corporate identity and corporate communications. They are discovering that conventional methods of redressing identity problems are becoming progressively less effective because, in our opinion, the traditional focus has viewed corporate identity and corporate communications as functional rather than as strategic. We suggest a much broadened view that looks at corporate communications as a three‐part system process – primary, secondary, and tertiary. In many companies these three are out of balance. Primary communication should present a positive image of the company and set the stage for a strong reputation. Secondary communication should be designed to support and reinforce primary communication. Tertiary communications should be positive and result in a superior reputation if the other two stages of corporate communication are properly conceived. The authors postulate that senior managers who implement this can invest their organisation with a competitive advantage.
Comparative study of wear mechanism of duplex treated M7 HSS drill bits
Authors: Yilbas B.S. , Rashid M. , Nizam M.
Published: July 2002

The surface coating of drill bits improves the tool life considerably and enhances the end product quality. The improved coating is desirable for long service operations. One of the methods to achieve this is to develop an interface layer between the coat and the tool base such that the transition of shear properties occurs across the interface layer. The application of duplex treatment (plasma pre‐nitriding before PVD TiN coating) to the tool surface becomes fruitful in this regard. In the present study, the wear properties of the duplex treated and untreated M7 HSS twist drill bits are examined. The wear tests are conducted on a dry base, and the feed rate and rotational speed are kept constant during the drilling tests. SEM and EDS are conducted to analyze the wear properties and metallurgical changes on the tool surface after the tests. It is found that the build up edge forms on the untreated tool surface, which in turn results in adhesion and abrasive wear. In the case of duplex treated drill bit, thinning of TiN coat is observed, but the coat is neither partially nor totally pealed off from the tool surface in the wear land.
A comparison of the friction and wear characteristics of two well‐known dispersions of MoS2 in oil
Authors: Domeir J.
Published: July 2002

Molybdenum disulphide dispersions in mineral oil have long been known to be good anti‐wear and anti‐friction lubricant additives. This study compares the friction and wear behaviour of two well‐known commercial MoS2 in oil dispersions using a four‐ball wear test machine. The two MoS2 dispersions were added to eight different commercial motor oils and their friction and wear characteristics are evaluated using a four‐ball friction and wear test procedure. Each of the base oils used was selected to represent a specific segment of motor oils, and none was selected because of any known compatibility with either of the two dispersions in this study.
Policy failure in vocational education and training: the introduction of National Vocational Qualifications (1986‐1990)
Authors: Williams Steve
Published: July 2002

One of the most prominent developments in vocational education and training in recent years has been the development of National Vocational Qualifications (NVQs) in England and Wales, based on the assessment of an individual’s competence at work. However, the initial implementation of the NVQ policy generated a considerable amount of criticism. The standards of occupational competence on which the NVQs are based were attacked for being too narrow; employers appeared reluctant to take up the new qualifications; and the introduction of NVQs appeared to exacerbate, rather than mitigate, the “jungle” of vocational qualifications. Drawing on in‐depth interviews with key informants and an analysis of relevant documentation this article ascribes the initial failure of the NVQ initiative to progress in the manner that its planners had originally anticipated to the existence of certain institutional constraints: the political imperative to manage high levels of youth unemployment; inadequate accountability and supervision in policy implementation; the presence of a renewed ethos of voluntarism in UK labour market policy; and the weakness of employers’ representative structures.
Empowerment: theory and practice
Authors: Wilkinson Adrian
Published: July 2002

In recent years, the term empowerment has become part of everyday management language. It has also been associated with popular management movements of the times such as human resource management (HRM) and total quality management (TQM). Empowerment is regarded as providing a solution to the age‐old problem of Taylorised and bureaucratic workplaces where creativity is stifled and workers become alienated, showing discontent through individual or collective means. However, there are significant problems with much of the prescriptive literature on empowerment, in that there is little detailed discussion of the problems employers may experience implementing empowerment or the conditions which are necessary for such an approach to be successful. It is assumed employees will simply welcome the new way of working. Moreover, it is also assumed that empowerment is a universal solution appropriate to all organisations in all circumstances. Empowerment itself is not seen in a contingent way. Such literature has also been criticised as superficial and furthermore as trivialising the conflict that exists within organisations.
Part‐time employment in Australia – Evidence for globalization?
Authors: de Ruyter Alex , Burgess John
Published: July 2002

Part‐time employment has expanded across most OECD countries over the past 25 years. Over the last two decades the Australian part‐time employment share has more than doubled to be around 26 percent of the workforce. This paper examines the growth in part‐time employment in Australia and in other OECD economies. In particular we are interested in assessing the extent to which global pressures, as represented by industry restructuring, provide a common explanation for the growing share of part‐time employment. Using shift share analysis the results suggest that industrial restructuring effects do explain some of the growth in part‐time employment, but more important is the growing intensity of part‐time employment across all sectors. This suggests that workforce feminisation, employer strategies and systems of labour regulation also require examination.
Schemebuilder: computer aided knowledge based design of mechatronic systems
Authors: Counsell Ian Porter David Dawson John , Duffy Marcus
Published: July 2002

Introduces the need for engineering knowledge management tools for storing past solutions and expert knowledge for the design of automatic precision machinery. The design of this type of machine, which is heavily utilised in modern manufacturing industry, is very complex, time‐consuming and potentially expensive. Describes the design and functionality of a novel computer aided rapid prototyping tool named Schemebuilder. The design is traced from its philosophical origins in the “Theory of domains” and how this can be used by the designer with the aid of the computer. The application of this underlining methodology for the design of precision machinery employing feedback control systems is also described. Finally an example is shown for the design of a control system for precise position control of a glass bottle making machine.
Genetic algorithm behaviour in the solution of an inverse thermal field problem
Authors: Wood R.L.
Published: July 2002

Discusses the performance of a simple genetic algorithm (GA) applied to a one‐dimensional inverse thermal field problem. Builds on these results by considering changes in GA performance that result from the introduction of non‐complementary crossover, stochastic remainder sampling and a combination of the two. Shows that, in comparison to the simple GA, non‐complementary cross‐over provides more rapid convergence, while stochastic remainder sampling without replacement has the opposite effect. However, when both strategies are combined, they provide considerably better performance with greater diversity within the population.
The effects of organisational change on employee psychological attachment An exploratory study
Authors: Bennett Haydn , Durkin Mark
Published: July 2002

Employee commitment is a concept which has attracted much attention in recent years. Research has focused on relationships between commitment and various facets of individual performance and on the psychological basis of the commitment itself. Profiles the pattern of employee commitment found in an exploratory study of employees of a large retail bank which is undergoing a process of both structural and cultural change. Three bases of employee commitment – internalised commitment, identification commitment and compliance commitment – are profiled against the pattern of commitment which the literature suggests will be found across various employee grades. Evidence from the exploratory research is presented which suggests that major change may result in the (at least partial) dissolution of internalised commitment on the part of employees, coupled with a corresponding increase in compliance commitment. Implications for the organisation and the future success of the change process are examined, together with recommendations for further research.
Taking stock: career planning for isolated, middle‐level professionals
Authors: Farmer Jane , Ward Grainne , Wood Lawraine
Published: July 2002

Middle‐level professionals working in one‐person library or information units, usually women, frequently experience obstacles to career progression, which are seen as insurmountable. Examines some of these obstacles, and suggests a possible approach to career planning incorporating a number of different strategies for change.
Learning to labour: an exploratory analysis of the “New Deal”
Authors: Turner Jason J. , McKinlay John W.
Published: July 2002

Explores, through semi‐structured interviews, participants’ perceptions of the “New Deal”. The paper draws on empirical data from research on the New Deal training scheme for unemployed young people aged between 18 and 24 years. It examines the ideology underpinning the New Deal training programme in terms of structure and its projected outcome. Under the New Deal training programme unemployed young people will be offered four “options” in the areas of training or work, with the elements of a personal adviser and quality assurances incorporated to achieve this. The government insists there will be “no fifth option of life on benefit”. This paper offers some evidence that there is disillusionment among participants regarding the programme and its four options. The accounts expressed question government rhetoric that the New Deal will prove to be “radically different from previous schemes” for getting the young unemployed “off benefits” and into employment.
Eyes wide shut? Querying the depth of call centre learning
Authors: Houlihan Maeve
Published: July 2002

Call centres are high‐pressure work environments characterised by routinisation, scripting, computer‐based monitoring and intensive performance targets. This promises a series of business advantages, but also risks counterproductive outcomes. Drawing on evidence from ethnographic field data, it is suggested that both desired and risked outcomes are mediated by personal modes of coping and organisational sustaining mechanisms. A central concern is to explore the underlying assumptions of call centre design and management, and to establish whether or to what extent information systems have been constructed as learning sites or behavioural control sites. When behavioural control is a primary goal this introduces a climate of resistance, further inflated by the culture of measurement and enforcement that is likely to ensue. In this environment, agent, manager and organisation become defensive and the main outcome is a destructive crisis of trust that creates important and difficult implications for the capacity to learn.
Learning organizations: the measurement of company performance
Authors: Leitch Claire , Harrison Richard , Burgoyne John , Blantern Chris
Published: July 2002

While the concept of the learning company has now become a fairly well‐established idea within academic and practitioner circles, it is still a concept which is in emergence and thus a certain amount of ambiguity and confusion surrounds it. It is, therefore, necessary not only to develop an understanding of the concept to the point at which it is possible to begin to understand the implications for practice, but also to establish the relationship between the presence and the development of learning company characteristics and organizational performance. Reviews the application of learning company ideas in a primarily small to medium‐sized enterprise environment, and using a case study approach considers the training, development and learning potential of one company after the application of The Learning Company Project questionnaire, developed by The Learning Company Project in Sheffield.
Training and education in contract catering management
Authors: Wilson Mervyn D.J. , Murray Anna E. , Black Margaret A. , McDowell David A.
Published: July 2002

In recent times the importance of training and education have been recognised as important tools to foster economic growth within companies and industries in the global marketplace. Unfortunately the UK hospitality industry in general has been unwilling to train and develop its managers. This paper examines the contract catering sector of the hospitality industry in Northern Ireland. It commences by investigating the educational qualifications and training of managers within the contract catering sector and then proceeds to discuss the transference of hospitality skills and practices.
The reflective (and competent) practitioner: a model of professional competence which seeks to harmonise the reflective practitioner and competence‐based approaches
Authors: Cheetham Graham , Chivers Geoff
Published: July 2002

In an earlier article, published in 1996, the authors described a provisional model of professional competence which attempted to harmonise the “reflective practitioner” paradigm (developed by Schön and now espoused by many professional education programmes) with competence‐based approaches. The latter included both the “functional outcomes” approach and the “personal competence” approach. Views on the composite model were sought from readers of this journal. The model was also tested as part of a programme of empirical work across 20 different professions. This paper offers a revised version of the model which takes account of the suggestions made by a significant number of respondents, as well as observations from the empirical work.
Models of magnetic circuits and their equivalent electrical diagrams
Authors: Deskur Jan
Published: July 2002

The paper presents a method of creating electrical equivalent diagrams of magnetic circuits. The method is based on bond‐graph techniques, using flux derivative as flow variable. Couplings between magnetic and electric part of the system are represented by gyrators. Simple models of magnetic branches, including non‐linear effects due to saturation, hysteresis and eddy currents, are presented. These models can be easily combined into magnetic circuit models, which can be transformed into dual electric equivalent circuit. Various equivalent circuits of transformers are discussed. The proposed models are simple and particularly useful for system‐level simulation of power electronic and motion control systems with magnetic elements. These models can be easily developed if needed. Theoretical considerations are illustrated by examples of digital simulation and experimental results.
Culture and educational administration
Authors: Hallinger Philip , Leithwood Kenneth
Published: July 2002

Outlines the rationale for exploring the role of culture in the practice of educational administration. Examines how culture fits into a broad theoretical framework for studying administrative behaviour in education. In doing so, distinguishes between the use of the societal culture construct as an exogenous and an endogenous variable. Argues that there is much conceptual leverage to be gained from employing culture as a variable in such a theoretical framework. Suggests a revisiting of the framework for studying educational administration developed by Getzels et al. almost 30 years ago. Finally, looks at the transmission of a knowledge base through training. Explores the implications that a cultural perspective has on the interpretation and use of knowledge as well as on its communication through preparation programmes. Contends that the cultural lens illuminates the limitations of the current knowledge base and supports the importance of this line of research in the future.